Implement ticket links and blocker state

app/Actions/Tickets/UpdateProjectTicket.php

@@ -18,9 +18,12 @@ class UpdateProjectTicket
     /**
      * @param  array{
      *     acceptance_criteria: string|null,
+     *     blocked_comment: string|null,
      *     description: string|null,
+     *     is_blocked: bool,
      *     ticket_priority_id: int,
      *     ticket_type_id: int,
+     *     parent_ticket_id: int|null,
      *     title: string
      * }  $ticketAttributes
      * @param  array<int, array{
@@ -36,6 +39,10 @@ class UpdateProjectTicket
         array $fieldValueAttributes,
     ): bool {
         return DB::transaction(function () use ($actor, $fieldValueAttributes, $ticket, $ticketAttributes): bool {
+            if (! $ticketAttributes['is_blocked']) {
+                $ticketAttributes['blocked_comment'] = null;
+            }
+
             $ticket->loadMissing([
                 'fieldValues.ticketFieldDefinition',
                 'fieldValues.userValue',
@@ -88,6 +95,14 @@ class UpdateProjectTicket
                 $ticket->acceptance_criteria,
                 $ticketAttributes['acceptance_criteria'],
             );
+            $this->trackScalarChange(
+                $changes,
+                $summaryLabels,
+                'blocked_comment',
+                'blocker comment',
+                $ticket->blocked_comment,
+                $ticketAttributes['blocked_comment'],
+            );
 
             if ($ticket->ticket_type_id !== $ticketAttributes['ticket_type_id']) {
                 $changes['ticket_type'] = [
@@ -105,6 +120,14 @@ class UpdateProjectTicket
                 $summaryLabels[] = 'priority';
             }
 
+            if ($ticket->is_blocked !== $ticketAttributes['is_blocked']) {
+                $changes['is_blocked'] = [
+                    'from' => $ticket->is_blocked,
+                    'to' => $ticketAttributes['is_blocked'],
+                ];
+                $summaryLabels[] = 'blocked state';
+            }
+
             if ($ticket->parent_ticket_id !== $ticketAttributes['parent_ticket_id']) {
                 $newParentTicket = $ticketAttributes['parent_ticket_id'] === null
                     ? null

app/Http/Controllers/ProjectTicketController.php

@@ -7,6 +7,7 @@ use App\Actions\Tickets\UpdateProjectTicket;
 use App\Http\Requests\UpdateProjectTicketRequest;
 use App\Models\Project;
 use App\Models\Ticket;
+use App\Models\TicketLink;
 use App\Models\User;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
@@ -32,6 +33,7 @@ class ProjectTicketController extends Controller
         return Inertia::render('projects/Ticket', [
             'canEditTicket' => $this->projectPermissionService->userHasPermission($request->user(), $project, 'edit'),
             'childTicketTree' => $this->buildChildTicketTree($ticket),
+            'linkedTickets' => $this->linkedTickets($ticket),
             'parentTicketOptions' => Ticket::query()
                 ->where('project_id', $project->id)
                 ->whereNotIn('id', $excludedParentIds)
@@ -54,6 +56,17 @@ class ProjectTicketController extends Controller
                 'worklogEntries.actor',
             ]),
             'ticketFieldDefinitions' => $project->ticketFieldDefinitions()->get(),
+            'ticketLinkOptions' => Ticket::query()
+                ->where('project_id', $project->id)
+                ->whereKeyNot($ticket->id)
+                ->orderByDesc('sequence_number')
+                ->get()
+                ->map(fn (Ticket $linkedTicket): array => [
+                    'id' => $linkedTicket->id,
+                    'ticket_key' => $linkedTicket->ticket_key,
+                    'title' => $linkedTicket->title,
+                ]),
+            'ticketLinkTypes' => $project->ticketLinkTypes()->get(),
             'ticketPriorities' => $project->ticketPriorities()->get(),
             'ticketTypes' => $project->ticketTypes()->get(),
             'users' => User::query()
@@ -124,4 +137,50 @@ class ProjectTicketController extends Controller
             ->values()
             ->all();
     }
+
+    /**
+     * @return array<int, array{
+     *     created_at: string|null,
+     *     id: int,
+     *     linked_ticket: array{id: int, ticket_key: string, title: string},
+     *     source_ticket_id: int,
+     *     target_ticket_id: int,
+     *     ticket_link_type: mixed,
+     *     ticket_link_type_id: int,
+     *     updated_at: string|null
+     * }>
+     */
+    private function linkedTickets(Ticket $ticket): array
+    {
+        return TicketLink::query()
+            ->with(['sourceTicket', 'targetTicket', 'ticketLinkType'])
+            ->where(function ($query) use ($ticket): void {
+                $query
+                    ->where('source_ticket_id', $ticket->id)
+                    ->orWhere('target_ticket_id', $ticket->id);
+            })
+            ->orderBy('id')
+            ->get()
+            ->map(function (TicketLink $ticketLink) use ($ticket): array {
+                $linkedTicket = $ticketLink->source_ticket_id === $ticket->id
+                    ? $ticketLink->targetTicket
+                    : $ticketLink->sourceTicket;
+
+                return [
+                    'created_at' => $ticketLink->created_at?->toISOString(),
+                    'id' => $ticketLink->id,
+                    'linked_ticket' => [
+                        'id' => $linkedTicket->id,
+                        'ticket_key' => $linkedTicket->ticket_key,
+                        'title' => $linkedTicket->title,
+                    ],
+                    'source_ticket_id' => $ticketLink->source_ticket_id,
+                    'target_ticket_id' => $ticketLink->target_ticket_id,
+                    'ticket_link_type' => $ticketLink->ticketLinkType,
+                    'ticket_link_type_id' => $ticketLink->ticket_link_type_id,
+                    'updated_at' => $ticketLink->updated_at?->toISOString(),
+                ];
+            })
+            ->all();
+    }
 }

app/Http/Controllers/ProjectTicketLinkController.php

@@ -0,0 +1,122 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Actions\ProjectPermissions\ProjectPermissionService;
+use App\Actions\Tickets\CreateTicketWorklogEntry;
+use App\Http\Requests\StoreTicketLinkRequest;
+use App\Models\Project;
+use App\Models\Ticket;
+use App\Models\TicketLink;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\DB;
+
+class ProjectTicketLinkController extends Controller
+{
+    public function __construct(
+        private readonly CreateTicketWorklogEntry $createTicketWorklogEntry,
+        private readonly ProjectPermissionService $projectPermissionService,
+    ) {}
+
+    public function store(
+        StoreTicketLinkRequest $request,
+        Project $project,
+        Ticket $ticket,
+    ): RedirectResponse {
+        abort_unless(
+            $this->projectPermissionService->userHasPermission($request->user(), $project, 'edit'),
+            403,
+        );
+
+        $linkedTicket = Ticket::query()
+            ->where('project_id', $project->id)
+            ->findOrFail($request->linkedTicketId());
+
+        [$sourceTicketId, $targetTicketId] = $this->normalizeTicketPair($ticket->id, $linkedTicket->id);
+
+        $ticketLink = DB::transaction(function () use ($linkedTicket, $request, $sourceTicketId, $targetTicketId, $ticket): TicketLink {
+            $ticketLink = TicketLink::query()->updateOrCreate(
+                [
+                    'source_ticket_id' => $sourceTicketId,
+                    'target_ticket_id' => $targetTicketId,
+                ],
+                [
+                    'ticket_link_type_id' => $request->ticketLinkTypeId(),
+                ],
+            );
+
+            $ticketLink->load('ticketLinkType');
+
+            $this->createTicketWorklogEntry->handle(
+                $ticket,
+                $request->user(),
+                'link_updated',
+                "Linked {$linkedTicket->ticket_key} as {$ticketLink->ticketLinkType->label}.",
+                [
+                    'linked_ticket_key' => $linkedTicket->ticket_key,
+                    'ticket_link_type' => $ticketLink->ticketLinkType->label,
+                ],
+            );
+
+            return $ticketLink;
+        });
+
+        return to_route('projects.tickets.show', [$project, $ticket])
+            ->with('status', "{$ticketLink->ticketLinkType->label} link was saved.");
+    }
+
+    public function destroy(
+        Request $request,
+        Project $project,
+        Ticket $ticket,
+        TicketLink $ticketLink,
+    ): RedirectResponse {
+        abort_unless(
+            $this->projectPermissionService->userHasPermission($request->user(), $project, 'edit'),
+            403,
+        );
+
+        $ticketLink->load(['sourceTicket', 'targetTicket', 'ticketLinkType']);
+
+        abort_unless(
+            $ticketLink->source_ticket_id === $ticket->id || $ticketLink->target_ticket_id === $ticket->id,
+            404,
+        );
+
+        $linkedTicket = $ticketLink->source_ticket_id === $ticket->id
+            ? $ticketLink->targetTicket
+            : $ticketLink->sourceTicket;
+
+        $label = $ticketLink->ticketLinkType->label;
+
+        DB::transaction(function () use ($label, $linkedTicket, $request, $ticket, $ticketLink): void {
+            $ticketLink->delete();
+
+            $this->createTicketWorklogEntry->handle(
+                $ticket,
+                $request->user(),
+                'link_removed',
+                "Removed {$label} link to {$linkedTicket->ticket_key}.",
+                [
+                    'linked_ticket_key' => $linkedTicket->ticket_key,
+                    'ticket_link_type' => $label,
+                ],
+            );
+        });
+
+        return to_route('projects.tickets.show', [$project, $ticket])
+            ->with('status', "{$label} link was removed.");
+    }
+
+    /**
+     * @return array{0: int, 1: int}
+     */
+    private function normalizeTicketPair(int $firstTicketId, int $secondTicketId): array
+    {
+        return [
+            min($firstTicketId, $secondTicketId),
+            max($firstTicketId, $secondTicketId),
+        ];
+    }
+}

app/Http/Controllers/ProjectTicketMetadataSettingsController.php

@@ -10,6 +10,7 @@ use App\Http\Requests\UpdateProjectNamedSettingRequest;
 use App\Http\Requests\UpdateTicketFieldDefinitionRequest;
 use App\Models\Project;
 use App\Models\TicketFieldDefinition;
+use App\Models\TicketLinkType;
 use App\Models\TicketPriority;
 use App\Models\TicketType;
 use Illuminate\Database\Eloquent\Model;
@@ -42,6 +43,7 @@ class ProjectTicketMetadataSettingsController extends Controller
             'project' => $project,
             'status' => session('status'),
             'ticketFieldDefinitions' => $project->ticketFieldDefinitions()->get(),
+            'ticketLinkTypes' => $project->ticketLinkTypes()->get(),
             'ticketPriorities' => $project->ticketPriorities()->get(),
             'ticketTypes' => $project->ticketTypes()->get(),
         ]);
@@ -249,6 +251,71 @@ class ProjectTicketMetadataSettingsController extends Controller
             ->with('status', "{$deletedLabel} field was removed.");
     }
 
+    public function storeLinkType(StoreProjectNamedSettingRequest $request, Project $project): RedirectResponse
+    {
+        $this->abortUnlessCanManage($request, $project);
+
+        $ticketLinkType = DB::transaction(function () use ($project, $request): TicketLinkType {
+            $ticketLinkType = $project->ticketLinkTypes()->create([
+                'label' => $request->validated('name'),
+                'position' => $project->ticketLinkTypes()->count() + 1,
+            ]);
+
+            $this->reorderModels(
+                $project->ticketLinkTypes()->whereKeyNot($ticketLinkType->id)->get()->values(),
+                $ticketLinkType,
+                $request->position() ?? $project->ticketLinkTypes()->count(),
+            );
+
+            return $ticketLinkType;
+        });
+
+        return to_route('projects.settings.metadata', $project)
+            ->with('status', "{$ticketLinkType->label} link type was added.");
+    }
+
+    public function updateLinkType(
+        UpdateProjectNamedSettingRequest $request,
+        Project $project,
+        TicketLinkType $ticketLinkType,
+    ): RedirectResponse {
+        $this->abortUnlessCanManage($request, $project);
+
+        DB::transaction(function () use ($project, $request, $ticketLinkType): void {
+            $ticketLinkType->update([
+                'label' => $request->validated('name'),
+            ]);
+
+            $this->reorderModels(
+                $project->ticketLinkTypes()->whereKeyNot($ticketLinkType->id)->get()->values(),
+                $ticketLinkType,
+                $request->position(),
+            );
+        });
+
+        return to_route('projects.settings.metadata', $project)
+            ->with('status', "{$ticketLinkType->fresh()->label} link type was updated.");
+    }
+
+    public function destroyLinkType(
+        Request $request,
+        Project $project,
+        TicketLinkType $ticketLinkType,
+    ): RedirectResponse {
+        $this->abortUnlessCanManage($request, $project);
+
+        $deletedLabel = $ticketLinkType->label;
+
+        DB::transaction(function () use ($project, $ticketLinkType): void {
+            $ticketLinkType->delete();
+
+            $this->persistOrderedModels($project->ticketLinkTypes()->get()->values());
+        });
+
+        return to_route('projects.settings.metadata', $project)
+            ->with('status', "{$deletedLabel} link type was removed.");
+    }
+
     private function abortUnlessCanManage(Request $request, Project $project): void
     {
         abort_unless(

app/Http/Requests/StoreTicketLinkRequest.php

@@ -0,0 +1,74 @@
+<?php
+
+namespace App\Http\Requests;
+
+use App\Models\Project;
+use App\Models\Ticket;
+use Illuminate\Contracts\Validation\ValidationRule;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+use Illuminate\Validation\Validator;
+
+class StoreTicketLinkRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     */
+    public function authorize(): bool
+    {
+        return $this->user() !== null;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        /** @var Project $project */
+        $project = $this->route('project');
+
+        return [
+            'linked_ticket_id' => [
+                'required',
+                'integer',
+                Rule::exists('tickets', 'id')->where('project_id', $project->id),
+            ],
+            'ticket_link_type_id' => [
+                'required',
+                'integer',
+                Rule::exists('ticket_link_types', 'id')->where('project_id', $project->id),
+            ],
+        ];
+    }
+
+    /**
+     * @return array<int, callable(Validator): void>
+     */
+    public function after(): array
+    {
+        return [
+            function (Validator $validator): void {
+                /** @var Ticket $ticket */
+                $ticket = $this->route('ticket');
+
+                $linkedTicketId = $this->input('linked_ticket_id');
+
+                if (is_numeric($linkedTicketId) && (int) $linkedTicketId === $ticket->id) {
+                    $validator->errors()->add('linked_ticket_id', 'A ticket cannot be linked to itself.');
+                }
+            },
+        ];
+    }
+
+    public function linkedTicketId(): int
+    {
+        return (int) $this->validated('linked_ticket_id');
+    }
+
+    public function ticketLinkTypeId(): int
+    {
+        return (int) $this->validated('ticket_link_type_id');
+    }
+}

app/Http/Requests/UpdateProjectTicketRequest.php

@@ -33,6 +33,7 @@ class UpdateProjectTicketRequest extends FormRequest
 
         return [
             'acceptance_criteria' => ['nullable', 'string'],
+            'blocked_comment' => ['nullable', 'string'],
             'description' => ['nullable', 'string'],
             'field_values' => ['array'],
             'field_values.*' => ['array'],
@@ -43,6 +44,7 @@ class UpdateProjectTicketRequest extends FormRequest
             ],
             'field_values.*.value_number' => ['nullable', 'numeric'],
             'field_values.*.value_user_id' => ['nullable', 'integer', Rule::exists('users', 'id')],
+            'is_blocked' => ['required', 'boolean'],
             'parent_ticket_id' => [
                 'nullable',
                 'integer',
@@ -116,6 +118,10 @@ class UpdateProjectTicketRequest extends FormRequest
                 ) {
                     $validator->errors()->add('ticket_type_id', 'Tickets with child tickets must keep a Parent type.');
                 }
+
+                if ($this->boolean('is_blocked') && blank($this->input('blocked_comment'))) {
+                    $validator->errors()->add('blocked_comment', 'Blocked tickets require a blocker comment.');
+                }
             },
         ];
     }
@@ -123,7 +129,9 @@ class UpdateProjectTicketRequest extends FormRequest
     /**
      * @return array{
      *     acceptance_criteria: string|null,
+     *     blocked_comment: string|null,
      *     description: string|null,
+     *     is_blocked: bool,
      *     parent_ticket_id: int|null,
      *     ticket_priority_id: int,
      *     ticket_type_id: int,
@@ -134,7 +142,9 @@ class UpdateProjectTicketRequest extends FormRequest
     {
         /** @var array{
          *     acceptance_criteria: string|null,
+         *     blocked_comment: string|null,
          *     description: string|null,
+         *     is_blocked: bool,
          *     parent_ticket_id: int|null,
          *     ticket_priority_id: int,
          *     ticket_type_id: int,
@@ -144,12 +154,16 @@ class UpdateProjectTicketRequest extends FormRequest
         $attributes = array_merge(
             [
                 'acceptance_criteria' => null,
+                'blocked_comment' => null,
                 'description' => null,
+                'is_blocked' => false,
                 'parent_ticket_id' => null,
             ],
             Arr::only($this->validated(), [
                 'acceptance_criteria',
+                'blocked_comment',
                 'description',
+                'is_blocked',
                 'parent_ticket_id',
                 'ticket_priority_id',
                 'ticket_type_id',

app/Models/Project.php

@@ -41,6 +41,12 @@ class Project extends Model
             ->orderBy('position');
     }
 
+    public function ticketLinkTypes(): HasMany
+    {
+        return $this->hasMany(TicketLinkType::class)
+            ->orderBy('position');
+    }
+
     public function ticketTypes(): HasMany
     {
         return $this->hasMany(TicketType::class)

app/Models/Ticket.php

@@ -12,7 +12,9 @@ use Illuminate\Database\Eloquent\Relations\HasMany;
 #[Fillable([
     'acceptance_criteria',
     'board_column_id',
+    'blocked_comment',
     'description',
+    'is_blocked',
     'parent_ticket_id',
     'project_id',
     'sequence_number',
@@ -26,6 +28,16 @@ class Ticket extends Model
     /** @use HasFactory<TicketFactory> */
     use HasFactory;
 
+    /**
+     * @return array<string, string>
+     */
+    protected function casts(): array
+    {
+        return [
+            'is_blocked' => 'boolean',
+        ];
+    }
+
     public function boardColumn(): BelongsTo
     {
         return $this->belongsTo(BoardColumn::class);
@@ -48,6 +60,18 @@ class Ticket extends Model
         return $this->belongsTo(Ticket::class, 'parent_ticket_id');
     }
 
+    public function ticketLinksAsSource(): HasMany
+    {
+        return $this->hasMany(TicketLink::class, 'source_ticket_id')
+            ->orderBy('id');
+    }
+
+    public function ticketLinksAsTarget(): HasMany
+    {
+        return $this->hasMany(TicketLink::class, 'target_ticket_id')
+            ->orderBy('id');
+    }
+
     public function project(): BelongsTo
     {
         return $this->belongsTo(Project::class);

app/Models/TicketLink.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Models;
+
+use Database\Factories\TicketLinkFactory;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+#[Fillable(['source_ticket_id', 'target_ticket_id', 'ticket_link_type_id'])]
+class TicketLink extends Model
+{
+    /** @use HasFactory<TicketLinkFactory> */
+    use HasFactory;
+
+    public function sourceTicket(): BelongsTo
+    {
+        return $this->belongsTo(Ticket::class, 'source_ticket_id');
+    }
+
+    public function targetTicket(): BelongsTo
+    {
+        return $this->belongsTo(Ticket::class, 'target_ticket_id');
+    }
+
+    public function ticketLinkType(): BelongsTo
+    {
+        return $this->belongsTo(TicketLinkType::class);
+    }
+}

app/Models/TicketLinkType.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace App\Models;
+
+use Database\Factories\TicketLinkTypeFactory;
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+#[Fillable(['label', 'position', 'project_id'])]
+class TicketLinkType extends Model
+{
+    /** @use HasFactory<TicketLinkTypeFactory> */
+    use HasFactory;
+
+    public function project(): BelongsTo
+    {
+        return $this->belongsTo(Project::class);
+    }
+
+    public function ticketLinks(): HasMany
+    {
+        return $this->hasMany(TicketLink::class)
+            ->orderBy('id');
+    }
+}

database/factories/TicketFactory.php

@@ -23,7 +23,9 @@ class TicketFactory extends Factory
         return [
             'acceptance_criteria' => fake()->paragraph(),
             'board_column_id' => null,
+            'blocked_comment' => null,
             'description' => fake()->paragraphs(2, true),
+            'is_blocked' => false,
             'parent_ticket_id' => null,
             'sequence_number' => 1,
             'ticket_key' => 'TEST-1',

database/factories/TicketLinkFactory.php

@@ -0,0 +1,75 @@
+<?php
+
+namespace Database\Factories;
+
+use App\Models\Ticket;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends Factory<TicketLink>
+ */
+class TicketLinkFactory extends Factory
+{
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'source_ticket_id' => null,
+            'target_ticket_id' => null,
+            'ticket_link_type_id' => null,
+        ];
+    }
+
+    public function configure(): static
+    {
+        return $this->afterMaking(function (TicketLink $ticketLink): void {
+            $sourceTicket = $ticketLink->source_ticket_id === null
+                ? Ticket::factory()->create()
+                : Ticket::query()->findOrFail($ticketLink->source_ticket_id);
+
+            $targetTicket = $ticketLink->target_ticket_id === null
+                ? Ticket::factory()->create([
+                    'project_id' => $sourceTicket->project_id,
+                    'ticket_priority_id' => $sourceTicket->ticket_priority_id,
+                    'ticket_type_id' => $sourceTicket->ticket_type_id,
+                    'sequence_number' => $sourceTicket->sequence_number + 1,
+                    'ticket_key' => "{$sourceTicket->project->key}-".($sourceTicket->sequence_number + 1),
+                ])
+                : Ticket::query()->findOrFail($ticketLink->target_ticket_id);
+
+            if ($sourceTicket->id === $targetTicket->id) {
+                $targetTicket = Ticket::factory()->create([
+                    'project_id' => $sourceTicket->project_id,
+                    'ticket_priority_id' => $sourceTicket->ticket_priority_id,
+                    'ticket_type_id' => $sourceTicket->ticket_type_id,
+                    'sequence_number' => $sourceTicket->sequence_number + 1,
+                    'ticket_key' => "{$sourceTicket->project->key}-".($sourceTicket->sequence_number + 1),
+                ]);
+            }
+
+            $ticketLinkType = $ticketLink->ticket_link_type_id === null
+                ? TicketLinkType::query()
+                    ->where('project_id', $sourceTicket->project_id)
+                    ->orderBy('position')
+                    ->first()
+                ?? TicketLinkType::factory()->for($sourceTicket->project)->create([
+                    'label' => 'Relates to',
+                    'position' => 1,
+                ])
+                : TicketLinkType::query()->findOrFail($ticketLink->ticket_link_type_id);
+
+            $sortedIds = [$sourceTicket->id, $targetTicket->id];
+            sort($sortedIds);
+
+            $ticketLink->source_ticket_id = $sortedIds[0];
+            $ticketLink->target_ticket_id = $sortedIds[1];
+            $ticketLink->ticket_link_type_id = $ticketLinkType->id;
+        });
+    }
+}

database/factories/TicketLinkTypeFactory.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Database\Factories;
+
+use App\Models\Project;
+use App\Models\TicketLinkType;
+use Illuminate\Database\Eloquent\Factories\Factory;
+
+/**
+ * @extends Factory<TicketLinkType>
+ */
+class TicketLinkTypeFactory extends Factory
+{
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'label' => fake()->unique()->words(2, true),
+            'position' => 1,
+            'project_id' => Project::factory(),
+        ];
+    }
+}

database/migrations/2026_03_25_073715_add_blocking_fields_to_tickets_table.php

@@ -0,0 +1,33 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('tickets', function (Blueprint $table) {
+            $table->boolean('is_blocked')
+                ->default(false)
+                ->after('parent_ticket_id');
+            $table->text('blocked_comment')
+                ->nullable()
+                ->after('is_blocked');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('tickets', function (Blueprint $table) {
+            $table->dropColumn(['blocked_comment', 'is_blocked']);
+        });
+    }
+};

database/migrations/2026_03_25_073715_create_ticket_link_types_table.php

@@ -0,0 +1,33 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('ticket_link_types', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('project_id')->constrained()->cascadeOnDelete();
+            $table->string('label');
+            $table->unsignedInteger('position');
+            $table->timestamps();
+
+            $table->unique(['project_id', 'label']);
+            $table->unique(['project_id', 'position']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('ticket_link_types');
+    }
+};

database/migrations/2026_03_25_073715_create_ticket_links_table.php

@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('ticket_links', function (Blueprint $table) {
+            $table->id();
+            $table->foreignId('ticket_link_type_id')->constrained()->cascadeOnDelete();
+            $table->foreignId('source_ticket_id')->constrained('tickets')->cascadeOnDelete();
+            $table->foreignId('target_ticket_id')->constrained('tickets')->cascadeOnDelete();
+            $table->timestamps();
+
+            $table->unique(['source_ticket_id', 'target_ticket_id']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('ticket_links');
+    }
+};

database/seeders/DatabaseSeeder.php

@@ -19,6 +19,8 @@ class DatabaseSeeder extends Seeder
             ProjectTicketMetadataSeeder::class,
             TicketSeeder::class,
             TicketFieldValueSeeder::class,
+            TicketLinkTypeSeeder::class,
+            TicketLinkSeeder::class,
             TicketWorklogEntrySeeder::class,
             TeamSeeder::class,
             ProjectAccessSeeder::class,

database/seeders/TicketLinkSeeder.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Database\Seeders;
+
+use App\Models\Project;
+use App\Models\Ticket;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
+use Illuminate\Database\Seeder;
+
+class TicketLinkSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     */
+    public function run(): void
+    {
+        Project::query()
+            ->with(['tickets', 'ticketLinkTypes'])
+            ->orderBy('id')
+            ->get()
+            ->each(function (Project $project): void {
+                /** @var Ticket|null $firstTicket */
+                $firstTicket = $project->tickets->sortBy('sequence_number')->values()->get(0);
+                /** @var Ticket|null $secondTicket */
+                $secondTicket = $project->tickets->sortBy('sequence_number')->values()->get(1);
+                /** @var TicketLinkType|null $ticketLinkType */
+                $ticketLinkType = $project->ticketLinkTypes->sortBy('position')->first();
+
+                if ($firstTicket === null || $secondTicket === null || $ticketLinkType === null) {
+                    return;
+                }
+
+                TicketLink::factory()->create([
+                    'source_ticket_id' => min($firstTicket->id, $secondTicket->id),
+                    'target_ticket_id' => max($firstTicket->id, $secondTicket->id),
+                    'ticket_link_type_id' => $ticketLinkType->id,
+                ]);
+            });
+    }
+}

database/seeders/TicketLinkTypeSeeder.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace Database\Seeders;
+
+use App\Models\Project;
+use App\Models\TicketLinkType;
+use Illuminate\Database\Seeder;
+
+class TicketLinkTypeSeeder extends Seeder
+{
+    /**
+     * Run the database seeds.
+     */
+    public function run(): void
+    {
+        Project::query()
+            ->orderBy('id')
+            ->get()
+            ->each(function (Project $project): void {
+                TicketLinkType::factory()
+                    ->count(2)
+                    ->sequence(
+                        ['label' => 'Relates to', 'position' => 1],
+                        ['label' => 'Blocks', 'position' => 2],
+                    )
+                    ->for($project)
+                    ->create();
+            });
+    }
+}

resources/js/pages/projects/Board.vue

@@ -136,13 +136,24 @@ const statusOptions = [
                             <Card
                                 v-for="ticket in boardColumn.tickets"
                                 :key="ticket.id"
-                                class="gap-0"
+                                :class="[
+                                    'gap-0',
+                                    ticket.is_blocked
+                                        ? 'border-amber-300 bg-amber-50/70 dark:border-amber-700/60 dark:bg-amber-950/30'
+                                        : '',
+                                ]"
                             >
                                 <CardHeader class="pb-4">
                                     <div class="flex flex-wrap gap-2">
                                         <Badge variant="outline">
                                             {{ ticket.ticket_key }}
                                         </Badge>
+                                        <Badge
+                                            v-if="ticket.is_blocked"
+                                            variant="destructive"
+                                        >
+                                            Blocked
+                                        </Badge>
                                         <Badge variant="secondary">
                                             {{ ticket.ticket_type.name }}
                                         </Badge>
@@ -169,6 +180,12 @@ const statusOptions = [
                                     >
                                         {{ ticket.description }}
                                     </CardDescription>
+                                    <CardDescription
+                                        v-if="ticket.is_blocked && ticket.blocked_comment"
+                                        class="mt-2 text-amber-900 dark:text-amber-200"
+                                    >
+                                        {{ ticket.blocked_comment }}
+                                    </CardDescription>
                                 </CardHeader>
 
                                 <CardContent v-if="canEditTickets" class="pt-0">

resources/js/pages/projects/Ticket.vue

@@ -1,5 +1,6 @@
 <script setup lang="ts">
-import { useForm, Head, Link } from '@inertiajs/vue3';
+import { Form, useForm, Head, Link } from '@inertiajs/vue3';
+import ProjectTicketLinkController from '@/actions/App/Http/Controllers/ProjectTicketLinkController';
 import ProjectTicketController from '@/actions/App/Http/Controllers/ProjectTicketController';
 import Heading from '@/components/Heading.vue';
 import InputError from '@/components/InputError.vue';
@@ -44,6 +45,7 @@ const breadcrumbs: BreadcrumbItem[] = [
 
 const form = useForm({
     acceptance_criteria: props.ticket.acceptance_criteria ?? '',
+    blocked_comment: props.ticket.blocked_comment ?? '',
     description: props.ticket.description ?? '',
     field_values: props.ticketFieldDefinitions.map((ticketFieldDefinition) => {
         const currentFieldValue = props.ticket.field_values?.find(
@@ -58,6 +60,7 @@ const form = useForm({
             value_user_id: currentFieldValue?.value_user_id ?? '',
         };
     }),
+    is_blocked: props.ticket.is_blocked,
     parent_ticket_id: props.ticket.parent_ticket_id ?? '',
     ticket_priority_id: props.ticket.ticket_priority_id,
     ticket_type_id: props.ticket.ticket_type_id,
@@ -284,6 +287,42 @@ const formatDateTime = (value: string): string => {
                                 />
                             </div>
 
+                            <div class="grid gap-3 rounded-xl border border-border p-4">
+                                <div class="flex items-center gap-3">
+                                    <input
+                                        id="is_blocked"
+                                        v-model="form.is_blocked"
+                                        type="checkbox"
+                                        :disabled="
+                                            !canEditTicket || form.processing
+                                        "
+                                        class="size-4 rounded border-input text-primary focus:ring-ring"
+                                    />
+                                    <Label for="is_blocked">
+                                        Mark ticket as blocked
+                                    </Label>
+                                </div>
+
+                                <div class="grid gap-2">
+                                    <Label for="blocked_comment">
+                                        Blocker comment
+                                    </Label>
+                                    <textarea
+                                        id="blocked_comment"
+                                        v-model="form.blocked_comment"
+                                        rows="3"
+                                        :disabled="
+                                            !canEditTicket || form.processing
+                                        "
+                                        class="rounded-md border border-input bg-background px-3 py-2 text-sm shadow-xs transition-[color,box-shadow] outline-none focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 disabled:cursor-not-allowed disabled:opacity-60"
+                                        placeholder="Describe what currently blocks progress on this ticket."
+                                    />
+                                    <InputError
+                                        :message="form.errors.blocked_comment"
+                                    />
+                                </div>
+                            </div>
+
                             <div class="grid gap-4">
                                 <div class="space-y-1">
                                     <h3 class="text-sm font-semibold">
@@ -388,6 +427,155 @@ const formatDateTime = (value: string): string => {
                 </Card>
 
                 <div class="space-y-6">
+                    <Card class="h-fit">
+                        <CardHeader>
+                            <CardTitle>Linked tickets</CardTitle>
+                            <CardDescription>
+                                Track cross-ticket relationships with
+                                project-defined link labels.
+                            </CardDescription>
+                        </CardHeader>
+
+                        <CardContent class="space-y-4">
+                            <Form
+                                v-if="
+                                    canEditTicket &&
+                                    ticketLinkTypes.length > 0 &&
+                                    ticketLinkOptions.length > 0
+                                "
+                                v-bind="
+                                    ProjectTicketLinkController.store.form({
+                                        project: project.id,
+                                        ticket: ticket.id,
+                                    })
+                                "
+                                class="grid gap-4 rounded-xl border border-dashed border-border p-4"
+                                v-slot="{ errors, processing }"
+                            >
+                                <div class="grid gap-2">
+                                    <Label for="ticket_link_type_id">
+                                        Link type
+                                    </Label>
+                                    <select
+                                        id="ticket_link_type_id"
+                                        name="ticket_link_type_id"
+                                        class="rounded-md border border-input bg-background px-3 py-2 text-sm shadow-xs transition-[color,box-shadow] outline-none focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50"
+                                    >
+                                        <option
+                                            v-for="ticketLinkType in ticketLinkTypes"
+                                            :key="ticketLinkType.id"
+                                            :value="ticketLinkType.id"
+                                        >
+                                            {{ ticketLinkType.label }}
+                                        </option>
+                                    </select>
+                                    <InputError
+                                        :message="errors.ticket_link_type_id"
+                                    />
+                                </div>
+
+                                <div class="grid gap-2">
+                                    <Label for="linked_ticket_id">
+                                        Linked ticket
+                                    </Label>
+                                    <select
+                                        id="linked_ticket_id"
+                                        name="linked_ticket_id"
+                                        class="rounded-md border border-input bg-background px-3 py-2 text-sm shadow-xs transition-[color,box-shadow] outline-none focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50"
+                                    >
+                                        <option
+                                            v-for="ticketLinkOption in ticketLinkOptions"
+                                            :key="ticketLinkOption.id"
+                                            :value="ticketLinkOption.id"
+                                        >
+                                            {{
+                                                `${ticketLinkOption.ticket_key} - ${ticketLinkOption.title}`
+                                            }}
+                                        </option>
+                                    </select>
+                                    <InputError
+                                        :message="errors.linked_ticket_id"
+                                    />
+                                </div>
+
+                                <Button
+                                    type="submit"
+                                    :disabled="processing"
+                                >
+                                    Save link
+                                </Button>
+                            </Form>
+
+                            <div
+                                v-if="linkedTickets.length === 0"
+                                class="rounded-xl border border-dashed border-border px-4 py-6 text-sm text-muted-foreground"
+                            >
+                                No ticket links are configured for this ticket
+                                yet.
+                            </div>
+
+                            <div v-else class="space-y-3">
+                                <div
+                                    v-for="linkedTicket in linkedTickets"
+                                    :key="linkedTicket.id"
+                                    class="rounded-xl border border-border px-4 py-4"
+                                >
+                                    <div class="flex flex-wrap items-center gap-2">
+                                        <Badge variant="secondary">
+                                            {{
+                                                linkedTicket.ticket_link_type
+                                                    .label
+                                            }}
+                                        </Badge>
+                                        <Link
+                                            :href="
+                                                showTicket({
+                                                    project: project.id,
+                                                    ticket: linkedTicket
+                                                        .linked_ticket.id,
+                                                })
+                                            "
+                                            class="font-medium text-foreground transition hover:text-primary"
+                                        >
+                                            {{
+                                                linkedTicket.linked_ticket
+                                                    .ticket_key
+                                            }}
+                                        </Link>
+                                    </div>
+                                    <p class="mt-2 text-sm text-muted-foreground">
+                                        {{ linkedTicket.linked_ticket.title }}
+                                    </p>
+
+                                    <Form
+                                        v-if="canEditTicket"
+                                        v-bind="
+                                            ProjectTicketLinkController.destroy.form(
+                                                {
+                                                    project: project.id,
+                                                    ticket: ticket.id,
+                                                    ticketLink:
+                                                        linkedTicket.id,
+                                                },
+                                            )
+                                        "
+                                        class="mt-3 flex justify-end"
+                                        v-slot="{ processing: deleting }"
+                                    >
+                                        <Button
+                                            type="submit"
+                                            variant="destructive"
+                                            size="sm"
+                                            :disabled="deleting"
+                                        >
+                                            Remove
+                                        </Button>
+                                    </Form>
+                                </div>
+                            </div>
+                        </CardContent>
+                    </Card>
+
                     <Card class="h-fit">
                         <CardHeader>
                             <CardTitle>Child tickets</CardTitle>

resources/js/pages/projects/settings/Metadata.vue

@@ -57,7 +57,7 @@ const breadcrumbs: BreadcrumbItem[] = [
                     </Badge>
                     <Heading
                         :title="`${project.name} ticket settings`"
-                        description="Configure project-specific ticket types, priorities, and custom field definitions."
+                        description="Configure project-specific ticket types, priorities, custom field definitions, and ticket link labels."
                     />
                 </div>
 
@@ -81,7 +81,7 @@ const breadcrumbs: BreadcrumbItem[] = [
                 {{ status }}
             </div>
 
-            <div class="grid gap-6 xl:grid-cols-3">
+            <div class="grid gap-6 xl:grid-cols-2">
                 <Card class="gap-0 overflow-hidden">
                     <CardHeader class="border-b">
                         <CardTitle>Ticket types</CardTitle>
@@ -497,6 +497,124 @@ const breadcrumbs: BreadcrumbItem[] = [
                         </div>
                     </CardContent>
                 </Card>
+
+                <Card class="gap-0 overflow-hidden">
+                    <CardHeader class="border-b">
+                        <CardTitle>Link types</CardTitle>
+                        <CardDescription>
+                            Define project-specific labels for ticket-to-ticket
+                            relationships.
+                        </CardDescription>
+                    </CardHeader>
+
+                    <CardContent class="space-y-4 p-6">
+                        <Form
+                            v-bind="
+                                ProjectTicketMetadataSettingsController.storeLinkType.form(
+                                    project.id,
+                                )
+                            "
+                            class="space-y-4 rounded-xl border border-dashed border-border p-4"
+                            v-slot="{ errors, processing }"
+                        >
+                            <div class="grid gap-2">
+                                <Label for="link-type-name">
+                                    New link type name
+                                </Label>
+                                <Input
+                                    id="link-type-name"
+                                    name="name"
+                                    required
+                                    placeholder="Relates to"
+                                />
+                                <InputError :message="errors.name" />
+                            </div>
+
+                            <Button type="submit" :disabled="processing">
+                                Add link type
+                            </Button>
+                        </Form>
+
+                        <div
+                            v-for="ticketLinkType in ticketLinkTypes"
+                            :key="ticketLinkType.id"
+                            class="rounded-xl border border-border p-4"
+                        >
+                            <Form
+                                v-bind="
+                                    ProjectTicketMetadataSettingsController.updateLinkType.form(
+                                        [project.id, ticketLinkType.id],
+                                    )
+                                "
+                                class="grid gap-4"
+                                v-slot="{ errors, processing }"
+                            >
+                                <div class="grid gap-2">
+                                    <Label
+                                        :for="`link-type-name-${ticketLinkType.id}`"
+                                    >
+                                        Label
+                                    </Label>
+                                    <Input
+                                        :id="`link-type-name-${ticketLinkType.id}`"
+                                        name="name"
+                                        :value="ticketLinkType.label"
+                                        required
+                                    />
+                                    <InputError :message="errors.name" />
+                                </div>
+
+                                <div class="grid gap-2">
+                                    <Label
+                                        :for="`link-type-position-${ticketLinkType.id}`"
+                                    >
+                                        Position
+                                    </Label>
+                                    <Input
+                                        :id="`link-type-position-${ticketLinkType.id}`"
+                                        name="position"
+                                        type="number"
+                                        min="1"
+                                        :max="ticketLinkTypes.length"
+                                        :value="ticketLinkType.position"
+                                        required
+                                    />
+                                    <InputError :message="errors.position" />
+                                </div>
+
+                                <div
+                                    class="flex flex-wrap justify-between gap-3"
+                                >
+                                    <Button
+                                        type="submit"
+                                        variant="outline"
+                                        :disabled="processing"
+                                    >
+                                        Save
+                                    </Button>
+                                </div>
+                            </Form>
+
+                            <Form
+                                v-bind="
+                                    ProjectTicketMetadataSettingsController.destroyLinkType.form(
+                                        [project.id, ticketLinkType.id],
+                                    )
+                                "
+                                class="mt-3 flex justify-end"
+                                v-slot="{ processing: deleting }"
+                            >
+                                <Button
+                                    type="submit"
+                                    variant="destructive"
+                                    :disabled="deleting"
+                                >
+                                    Delete
+                                </Button>
+                            </Form>
+                        </div>
+                    </CardContent>
+                </Card>
             </div>
         </div>
     </AppLayout>

resources/js/types/models/ticket-link-model.ts

@@ -0,0 +1,14 @@
+import type { TicketLinkTypeModel } from '@/types/models/ticket-link-type-model';
+import type { TicketReferenceModel } from '@/types/models/ticket-reference-model';
+
+export type TicketLinkModel = {
+    id: number;
+    linked_ticket: TicketReferenceModel;
+    source_ticket_id: number;
+    target_ticket_id: number;
+    ticket_link_type: TicketLinkTypeModel;
+    ticket_link_type_id: number;
+    created_at: string;
+    updated_at: string;
+    [key: string]: unknown;
+};

resources/js/types/models/ticket-link-type-model.ts

@@ -0,0 +1,9 @@
+export type TicketLinkTypeModel = {
+    id: number;
+    label: string;
+    position: number;
+    project_id: number;
+    created_at: string;
+    updated_at: string;
+    [key: string]: unknown;
+};

resources/js/types/models/ticket-model.ts

@@ -7,8 +7,10 @@ export type TicketModel = {
     id: number;
     acceptance_criteria: string | null;
     board_column_id: number | null;
+    blocked_comment: string | null;
     description: string | null;
     field_values?: TicketFieldValueModel[];
+    is_blocked: boolean;
     parent_ticket_id: number | null;
     project_id: number;
     sequence_number: number;

resources/js/types/models/ticket-reference-model.ts

@@ -0,0 +1,5 @@
+export type TicketReferenceModel = {
+    id: number;
+    ticket_key: string;
+    title: string;
+};

resources/js/types/page-props.ts

@@ -2,6 +2,9 @@ import type { BoardColumnModel } from '@/types/models/board-column-model';
 import type { ProjectModel } from '@/types/models/project-model';
 import type { TeamModel } from '@/types/models/team-model';
 import type { TicketFieldDefinitionModel } from '@/types/models/ticket-field-definition-model';
+import type { TicketLinkModel } from '@/types/models/ticket-link-model';
+import type { TicketLinkTypeModel } from '@/types/models/ticket-link-type-model';
+import type { TicketReferenceModel } from '@/types/models/ticket-reference-model';
 import type { TicketModel } from '@/types/models/ticket-model';
 import type { TicketPriorityModel } from '@/types/models/ticket-priority-model';
 import type { TicketTreeNodeModel } from '@/types/models/ticket-tree-node-model';
@@ -66,6 +69,7 @@ export type ProjectTicketMetadataSettingsPageProps = {
     project: ProjectModel;
     status?: string | null;
     ticketFieldDefinitions: TicketFieldDefinitionModel[];
+    ticketLinkTypes: TicketLinkTypeModel[];
     ticketPriorities: TicketPriorityModel[];
     ticketTypes: TicketTypeModel[];
 };
@@ -84,15 +88,14 @@ export type ProjectBacklogPageProps = {
 export type ProjectTicketPageProps = {
     canEditTicket: boolean;
     childTicketTree: TicketTreeNodeModel[];
-    parentTicketOptions: Array<{
+    linkedTickets: TicketLinkModel[];
-        id: number;
+    parentTicketOptions: TicketReferenceModel[];
-        ticket_key: string;
-        title: string;
-    }>;
     project: ProjectModel;
     status?: string | null;
     ticket: TicketModel;
     ticketFieldDefinitions: TicketFieldDefinitionModel[];
+    ticketLinkOptions: TicketReferenceModel[];
+    ticketLinkTypes: TicketLinkTypeModel[];
     ticketPriorities: TicketPriorityModel[];
     ticketTypes: TicketTypeModel[];
     users: UserModel[];

routes/web.php

@@ -6,6 +6,7 @@ use App\Http\Controllers\ProjectBoardController;
 use App\Http\Controllers\ProjectBoardSettingsController;
 use App\Http\Controllers\ProjectController;
 use App\Http\Controllers\ProjectTicketController;
+use App\Http\Controllers\ProjectTicketLinkController;
 use App\Http\Controllers\ProjectTicketMetadataSettingsController;
 use App\Http\Controllers\TeamController;
 use Illuminate\Support\Facades\Route;
@@ -39,6 +40,11 @@ Route::middleware(['auth', 'verified'])->group(function () {
             ->name('projects.tickets.show');
         Route::patch('projects/{project}/tickets/{ticket}', [ProjectTicketController::class, 'update'])
             ->name('projects.tickets.update');
+        Route::post('projects/{project}/tickets/{ticket}/links', [ProjectTicketLinkController::class, 'store'])
+            ->name('projects.tickets.links.store');
+        Route::delete('projects/{project}/tickets/{ticket}/links/{ticketLink}', [ProjectTicketLinkController::class, 'destroy'])
+            ->withoutScopedBindings()
+            ->name('projects.tickets.links.destroy');
         Route::patch('projects/{project}/tickets/{ticket}/status', [ProjectBoardController::class, 'move'])
             ->name('projects.tickets.status.update');
         Route::get('projects/{project}/settings/board', [ProjectBoardSettingsController::class, 'show'])
@@ -69,6 +75,12 @@ Route::middleware(['auth', 'verified'])->group(function () {
             ->name('projects.settings.metadata.fields.update');
         Route::delete('projects/{project}/settings/metadata/fields/{ticketFieldDefinition}', [ProjectTicketMetadataSettingsController::class, 'destroyFieldDefinition'])
             ->name('projects.settings.metadata.fields.destroy');
+        Route::post('projects/{project}/settings/metadata/link-types', [ProjectTicketMetadataSettingsController::class, 'storeLinkType'])
+            ->name('projects.settings.metadata.link-types.store');
+        Route::patch('projects/{project}/settings/metadata/link-types/{ticketLinkType}', [ProjectTicketMetadataSettingsController::class, 'updateLinkType'])
+            ->name('projects.settings.metadata.link-types.update');
+        Route::delete('projects/{project}/settings/metadata/link-types/{ticketLinkType}', [ProjectTicketMetadataSettingsController::class, 'destroyLinkType'])
+            ->name('projects.settings.metadata.link-types.destroy');
     });
 });
 

tests/Feature/Models/TicketLinkTest.php

@@ -0,0 +1,93 @@
+<?php
+
+namespace Tests\Feature\Models;
+
+use App\Actions\ProjectTicketMetadata\InitializeProjectTicketMetadata;
+use App\Models\Project;
+use App\Models\Ticket;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
+use App\Models\TicketPriority;
+use Database\Seeders\ProjectSeeder;
+use Database\Seeders\ProjectTicketMetadataSeeder;
+use Database\Seeders\TicketLinkSeeder;
+use Database\Seeders\TicketLinkTypeSeeder;
+use Database\Seeders\TicketSeeder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class TicketLinkTest extends TestCase
+{
+    use RefreshDatabase;
+
+    /**
+     * Ensure the ticket link factory normalizes the stored source and target ticket ids.
+     */
+    public function test_ticket_link_factory_normalizes_ticket_order(): void
+    {
+        $project = Project::factory()->create([
+            'key' => 'CORE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $taskType = $project->ticketTypes()->where('system_key', 'task')->firstOrFail();
+
+        $firstTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'CORE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $secondTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'CORE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+
+        $ticketLink = TicketLink::factory()->create([
+            'source_ticket_id' => $secondTicket->id,
+            'target_ticket_id' => $firstTicket->id,
+            'ticket_link_type_id' => $ticketLinkType->id,
+        ]);
+
+        $this->assertSame($firstTicket->id, $ticketLink->source_ticket_id);
+        $this->assertSame($secondTicket->id, $ticketLink->target_ticket_id);
+    }
+
+    /**
+     * Ensure the ticket link seeder creates dummy links for seeded projects.
+     */
+    public function test_ticket_link_seeder_creates_dummy_links_for_seeded_projects(): void
+    {
+        $this->seed([
+            ProjectSeeder::class,
+            ProjectTicketMetadataSeeder::class,
+            TicketSeeder::class,
+            TicketLinkTypeSeeder::class,
+            TicketLinkSeeder::class,
+        ]);
+
+        $coreProject = Project::query()->where('key', 'CORE')->firstOrFail();
+        $seededTickets = Ticket::query()
+            ->where('project_id', $coreProject->id)
+            ->orderBy('sequence_number')
+            ->get();
+
+        $this->assertDatabaseHas('ticket_links', [
+            'source_ticket_id' => $seededTickets[0]->id,
+            'target_ticket_id' => $seededTickets[1]->id,
+        ]);
+    }
+}

tests/Feature/Models/TicketLinkTypeTest.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Tests\Feature\Models;
+
+use App\Models\Project;
+use App\Models\TicketLinkType;
+use Database\Seeders\ProjectSeeder;
+use Database\Seeders\TicketLinkTypeSeeder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class TicketLinkTypeTest extends TestCase
+{
+    use RefreshDatabase;
+
+    /**
+     * Ensure the ticket link type factory creates project-scoped labels.
+     */
+    public function test_ticket_link_type_factory_creates_project_scoped_labels(): void
+    {
+        $ticketLinkType = TicketLinkType::factory()->create();
+
+        $this->assertNotNull($ticketLinkType->project_id);
+        $this->assertIsString($ticketLinkType->label);
+    }
+
+    /**
+     * Ensure the ticket link type seeder creates default labels for seeded projects.
+     */
+    public function test_ticket_link_type_seeder_creates_default_labels_for_projects(): void
+    {
+        $this->seed([
+            ProjectSeeder::class,
+            TicketLinkTypeSeeder::class,
+        ]);
+
+        $coreProject = Project::query()->where('key', 'CORE')->firstOrFail();
+
+        $this->assertDatabaseHas('ticket_link_types', [
+            'project_id' => $coreProject->id,
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+
+        $this->assertDatabaseHas('ticket_link_types', [
+            'project_id' => $coreProject->id,
+            'label' => 'Blocks',
+            'position' => 2,
+        ]);
+    }
+}

tests/Feature/Models/TicketTest.php

@@ -7,6 +7,8 @@ use App\Models\Project;
 use App\Models\Ticket;
 use App\Models\TicketFieldDefinition;
 use App\Models\TicketFieldValue;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
 use App\Models\TicketPriority;
 use App\Models\TicketWorklogEntry;
 use Database\Seeders\BoardColumnSeeder;
@@ -165,4 +167,72 @@ class TicketTest extends TestCase
         $this->assertSame($parentTicket->id, $childTicket->fresh()->parentTicket?->id);
         $this->assertSame([$childTicket->id], $parentTicket->fresh()->childTickets->modelKeys());
     }
+
+    /**
+     * Ensure the blocked flag is cast to a boolean for board and detail rendering.
+     */
+    public function test_ticket_blocked_state_is_cast_to_boolean(): void
+    {
+        $ticket = Ticket::factory()->create([
+            'blocked_comment' => 'Waiting for environment access.',
+            'is_blocked' => 1,
+        ]);
+
+        $freshTicket = $ticket->fresh();
+
+        $this->assertTrue($freshTicket->is_blocked);
+        $this->assertSame('Waiting for environment access.', $freshTicket->blocked_comment);
+    }
+
+    /**
+     * Ensure tickets expose incoming and outgoing link relations.
+     */
+    public function test_ticket_link_relations_are_available(): void
+    {
+        $project = Project::factory()->create([
+            'key' => 'CORE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $taskType = $project->ticketTypes()->where('system_key', 'task')->firstOrFail();
+
+        $sourceTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'CORE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $targetTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'CORE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+
+        $ticketLink = TicketLink::factory()->create([
+            'source_ticket_id' => $sourceTicket->id,
+            'target_ticket_id' => $targetTicket->id,
+            'ticket_link_type_id' => $ticketLinkType->id,
+        ]);
+
+        $this->assertSame(
+            [$ticketLink->id],
+            $sourceTicket->fresh()->ticketLinksAsSource->modelKeys(),
+        );
+        $this->assertSame(
+            [$ticketLink->id],
+            $targetTicket->fresh()->ticketLinksAsTarget->modelKeys(),
+        );
+    }
 }

tests/Feature/Projects/ProjectTicketControllerTest.php

@@ -8,6 +8,8 @@ use App\Models\Project;
 use App\Models\Ticket;
 use App\Models\TicketFieldDefinition;
 use App\Models\TicketFieldValue;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
 use App\Models\TicketPriority;
 use App\Models\TicketWorklogEntry;
 use App\Models\User;
@@ -40,6 +42,10 @@ class ProjectTicketControllerTest extends TestCase
             'label' => 'Story Points',
             'position' => 1,
         ]);
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
 
         $ticket = Ticket::factory()->create([
             'project_id' => $project->id,
@@ -49,6 +55,14 @@ class ProjectTicketControllerTest extends TestCase
             'ticket_type_id' => $project->ticketTypes()->firstOrFail()->id,
             'title' => 'Ticket detail test',
         ]);
+        $linkedTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'CORE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $project->ticketTypes()->firstOrFail()->id,
+            'title' => 'Linked ticket',
+        ]);
 
         TicketFieldValue::factory()->create([
             'ticket_field_definition_id' => $fieldDefinition->id,
@@ -56,6 +70,11 @@ class ProjectTicketControllerTest extends TestCase
             'value_number' => 5,
             'value_user_id' => null,
         ]);
+        TicketLink::factory()->create([
+            'source_ticket_id' => $ticket->id,
+            'target_ticket_id' => $linkedTicket->id,
+            'ticket_link_type_id' => $ticketLinkType->id,
+        ]);
 
         TicketWorklogEntry::factory()->create([
             'actor_id' => $viewer->id,
@@ -76,6 +95,8 @@ class ProjectTicketControllerTest extends TestCase
                 ->where('ticket.field_values.0.ticket_field_definition.label', 'Story Points')
                 ->where('ticket.field_values.0.value_number', 5)
                 ->where('ticket.worklog_entries.0.actor.name', $viewer->name)
+                ->where('linkedTickets.0.linked_ticket.ticket_key', 'CORE-2')
+                ->where('linkedTickets.0.ticket_link_type.label', 'Relates to')
                 ->where('canEditTicket', false),
             );
     }
@@ -108,6 +129,9 @@ class ProjectTicketControllerTest extends TestCase
                 'title' => 'Updated title',
                 'description' => 'Updated description',
                 'acceptance_criteria' => 'Updated criteria',
+                'blocked_comment' => $ticket->blocked_comment,
+                'is_blocked' => $ticket->is_blocked,
+                'parent_ticket_id' => $ticket->parent_ticket_id,
                 'ticket_type_id' => $ticket->ticket_type_id,
                 'ticket_priority_id' => $ticket->ticket_priority_id,
                 'field_values' => [],
@@ -186,6 +210,9 @@ class ProjectTicketControllerTest extends TestCase
                 'title' => 'Updated title',
                 'description' => 'Updated description',
                 'acceptance_criteria' => 'Updated acceptance criteria',
+                'blocked_comment' => $ticket->blocked_comment,
+                'is_blocked' => $ticket->is_blocked,
+                'parent_ticket_id' => $ticket->parent_ticket_id,
                 'ticket_type_id' => $parentType->id,
                 'ticket_priority_id' => $highPriority->id,
                 'field_values' => [
@@ -276,6 +303,8 @@ class ProjectTicketControllerTest extends TestCase
                 'title' => $childTicket->title,
                 'description' => $childTicket->description,
                 'acceptance_criteria' => $childTicket->acceptance_criteria,
+                'blocked_comment' => $childTicket->blocked_comment,
+                'is_blocked' => $childTicket->is_blocked,
                 'parent_ticket_id' => $candidateParent->id,
                 'ticket_type_id' => $childTicket->ticket_type_id,
                 'ticket_priority_id' => $childTicket->ticket_priority_id,
@@ -330,6 +359,8 @@ class ProjectTicketControllerTest extends TestCase
                 'title' => $childTicket->title,
                 'description' => $childTicket->description,
                 'acceptance_criteria' => $childTicket->acceptance_criteria,
+                'blocked_comment' => $childTicket->blocked_comment,
+                'is_blocked' => $childTicket->is_blocked,
                 'parent_ticket_id' => $parentTicket->id,
                 'ticket_type_id' => $childTicket->ticket_type_id,
                 'ticket_priority_id' => $childTicket->ticket_priority_id,
@@ -422,4 +453,134 @@ class ProjectTicketControllerTest extends TestCase
                 ->where('childTicketTree.1.ticket_key', $directTask->ticket_key),
             );
     }
+
+    /**
+     * Ensure blocked tickets require a blocker comment.
+     */
+    public function test_blocked_tickets_require_a_blocker_comment_when_updating(): void
+    {
+        $editor = User::factory()->create();
+        $project = Project::factory()->create();
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $ticket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $project->ticketTypes()->firstOrFail()->id,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $editor, ['edit', 'view']);
+
+        $this->actingAs($editor)
+            ->from(route('projects.tickets.show', [$project, $ticket]))
+            ->patch(route('projects.tickets.update', [$project, $ticket]), [
+                'title' => $ticket->title,
+                'description' => $ticket->description,
+                'acceptance_criteria' => $ticket->acceptance_criteria,
+                'ticket_type_id' => $ticket->ticket_type_id,
+                'ticket_priority_id' => $ticket->ticket_priority_id,
+                'parent_ticket_id' => $ticket->parent_ticket_id,
+                'is_blocked' => true,
+                'blocked_comment' => '',
+                'field_values' => [],
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHasErrors('blocked_comment');
+
+        $this->assertDatabaseHas('tickets', [
+            'id' => $ticket->id,
+            'is_blocked' => false,
+            'blocked_comment' => null,
+        ]);
+    }
+
+    /**
+     * Ensure blocking and unblocking a ticket persists the state and logs both changes.
+     */
+    public function test_users_with_edit_permission_can_block_and_unblock_tickets(): void
+    {
+        $editor = User::factory()->create();
+        $project = Project::factory()->create([
+            'key' => 'CORE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $ticket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'CORE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $project->ticketTypes()->firstOrFail()->id,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $editor, ['edit', 'view']);
+
+        $this->actingAs($editor)
+            ->patch(route('projects.tickets.update', [$project, $ticket]), [
+                'title' => $ticket->title,
+                'description' => $ticket->description,
+                'acceptance_criteria' => $ticket->acceptance_criteria,
+                'ticket_type_id' => $ticket->ticket_type_id,
+                'ticket_priority_id' => $ticket->ticket_priority_id,
+                'parent_ticket_id' => $ticket->parent_ticket_id,
+                'is_blocked' => true,
+                'blocked_comment' => 'Waiting for dependency approval.',
+                'field_values' => [],
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHas('status', 'CORE-1 was updated.');
+
+        $this->assertDatabaseHas('tickets', [
+            'id' => $ticket->id,
+            'is_blocked' => true,
+            'blocked_comment' => 'Waiting for dependency approval.',
+        ]);
+
+        $this->assertDatabaseHas('ticket_worklog_entries', [
+            'ticket_id' => $ticket->id,
+            'actor_id' => $editor->id,
+            'entry_type' => 'updated',
+            'summary' => 'Updated blocker comment and blocked state.',
+        ]);
+
+        $this->actingAs($editor)
+            ->patch(route('projects.tickets.update', [$project, $ticket]), [
+                'title' => $ticket->title,
+                'description' => $ticket->description,
+                'acceptance_criteria' => $ticket->acceptance_criteria,
+                'ticket_type_id' => $ticket->ticket_type_id,
+                'ticket_priority_id' => $ticket->ticket_priority_id,
+                'parent_ticket_id' => $ticket->parent_ticket_id,
+                'is_blocked' => false,
+                'blocked_comment' => '',
+                'field_values' => [],
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHas('status', 'CORE-1 was updated.');
+
+        $this->assertDatabaseHas('tickets', [
+            'id' => $ticket->id,
+            'is_blocked' => false,
+            'blocked_comment' => null,
+        ]);
+
+        $this->assertSame(
+            2,
+            TicketWorklogEntry::query()
+                ->where('ticket_id', $ticket->id)
+                ->where('entry_type', 'updated')
+                ->where('summary', 'Updated blocker comment and blocked state.')
+                ->count(),
+        );
+    }
 }

tests/Feature/Projects/ProjectTicketLinkControllerTest.php

@@ -0,0 +1,201 @@
+<?php
+
+namespace Tests\Feature\Projects;
+
+use App\Actions\ProjectPermissions\ProjectPermissionService;
+use App\Actions\ProjectTicketMetadata\InitializeProjectTicketMetadata;
+use App\Models\Project;
+use App\Models\Ticket;
+use App\Models\TicketLink;
+use App\Models\TicketLinkType;
+use App\Models\TicketPriority;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class ProjectTicketLinkControllerTest extends TestCase
+{
+    use RefreshDatabase;
+
+    /**
+     * Ensure users with edit permission can link tickets and create a worklog entry.
+     */
+    public function test_users_with_edit_permission_can_link_tickets(): void
+    {
+        $user = User::factory()->create();
+        $project = Project::factory()->create([
+            'key' => 'CORE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $taskType = $project->ticketTypes()->where('system_key', 'task')->firstOrFail();
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+        $ticket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'CORE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $linkedTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'CORE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $user, ['edit', 'view']);
+
+        $this->actingAs($user)
+            ->post(route('projects.tickets.links.store', [$project, $ticket]), [
+                'linked_ticket_id' => $linkedTicket->id,
+                'ticket_link_type_id' => $ticketLinkType->id,
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHas('status', 'Relates to link was saved.');
+
+        $this->assertDatabaseHas('ticket_links', [
+            'source_ticket_id' => min($ticket->id, $linkedTicket->id),
+            'target_ticket_id' => max($ticket->id, $linkedTicket->id),
+            'ticket_link_type_id' => $ticketLinkType->id,
+        ]);
+
+        $this->assertDatabaseHas('ticket_worklog_entries', [
+            'ticket_id' => $ticket->id,
+            'actor_id' => $user->id,
+            'entry_type' => 'link_updated',
+            'summary' => 'Linked CORE-2 as Relates to.',
+        ]);
+    }
+
+    /**
+     * Ensure ticket links cannot target the current ticket or a ticket from another project.
+     */
+    public function test_ticket_links_must_target_other_tickets_within_the_same_project(): void
+    {
+        $user = User::factory()->create();
+        $project = Project::factory()->create();
+        $otherProject = Project::factory()->create();
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+        app(InitializeProjectTicketMetadata::class)->handle($otherProject);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $otherPriority = TicketPriority::factory()->for($otherProject)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $taskType = $project->ticketTypes()->where('system_key', 'task')->firstOrFail();
+        $otherTaskType = $otherProject->ticketTypes()->where('system_key', 'task')->firstOrFail();
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+        $ticket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'APP-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $foreignTicket = Ticket::factory()->create([
+            'project_id' => $otherProject->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'OPS-1',
+            'ticket_priority_id' => $otherPriority->id,
+            'ticket_type_id' => $otherTaskType->id,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $user, ['edit', 'view']);
+
+        $this->actingAs($user)
+            ->from(route('projects.tickets.show', [$project, $ticket]))
+            ->post(route('projects.tickets.links.store', [$project, $ticket]), [
+                'linked_ticket_id' => $ticket->id,
+                'ticket_link_type_id' => $ticketLinkType->id,
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHasErrors('linked_ticket_id');
+
+        $this->actingAs($user)
+            ->from(route('projects.tickets.show', [$project, $ticket]))
+            ->post(route('projects.tickets.links.store', [$project, $ticket]), [
+                'linked_ticket_id' => $foreignTicket->id,
+                'ticket_link_type_id' => $ticketLinkType->id,
+            ])
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHasErrors('linked_ticket_id');
+    }
+
+    /**
+     * Ensure users with edit permission can remove ticket links.
+     */
+    public function test_users_with_edit_permission_can_remove_ticket_links(): void
+    {
+        $user = User::factory()->create();
+        $project = Project::factory()->create([
+            'key' => 'CORE',
+        ]);
+
+        app(InitializeProjectTicketMetadata::class)->handle($project);
+
+        $priority = TicketPriority::factory()->for($project)->create([
+            'name' => 'Medium',
+            'position' => 1,
+        ]);
+        $taskType = $project->ticketTypes()->where('system_key', 'task')->firstOrFail();
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+        $ticket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 1,
+            'ticket_key' => 'CORE-1',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $linkedTicket = Ticket::factory()->create([
+            'project_id' => $project->id,
+            'sequence_number' => 2,
+            'ticket_key' => 'CORE-2',
+            'ticket_priority_id' => $priority->id,
+            'ticket_type_id' => $taskType->id,
+        ]);
+        $ticketLink = TicketLink::factory()->create([
+            'source_ticket_id' => min($ticket->id, $linkedTicket->id),
+            'target_ticket_id' => max($ticket->id, $linkedTicket->id),
+            'ticket_link_type_id' => $ticketLinkType->id,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $user, ['edit', 'view']);
+
+        $this->actingAs($user)
+            ->delete(route('projects.tickets.links.destroy', [$project, $ticket, $ticketLink]))
+            ->assertRedirect(route('projects.tickets.show', [$project, $ticket]))
+            ->assertSessionHas('status', 'Relates to link was removed.');
+
+        $this->assertDatabaseMissing('ticket_links', [
+            'id' => $ticketLink->id,
+        ]);
+
+        $this->assertDatabaseHas('ticket_worklog_entries', [
+            'ticket_id' => $ticket->id,
+            'actor_id' => $user->id,
+            'entry_type' => 'link_removed',
+            'summary' => 'Removed Relates to link to CORE-2.',
+        ]);
+    }
+}

tests/Feature/Projects/ProjectTicketMetadataSettingsControllerTest.php

@@ -5,6 +5,7 @@ namespace Tests\Feature\Projects;
 use App\Actions\ProjectPermissions\ProjectPermissionService;
 use App\Models\Project;
 use App\Models\TicketFieldDefinition;
+use App\Models\TicketLinkType;
 use App\Models\TicketPriority;
 use App\Models\TicketType;
 use App\Models\User;
@@ -27,6 +28,10 @@ class ProjectTicketMetadataSettingsControllerTest extends TestCase
             'name' => 'Bug',
             'position' => 3,
         ]);
+        TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
 
         app(ProjectPermissionService::class)->syncUserPermissions($project, $user, ['edit']);
 
@@ -37,7 +42,8 @@ class ProjectTicketMetadataSettingsControllerTest extends TestCase
                 ->component('projects/settings/Metadata')
                 ->where('ticketTypes.0.name', 'Task')
                 ->where('ticketTypes.1.name', 'Parent')
-                ->where('ticketTypes.2.name', 'Bug'),
+                ->where('ticketTypes.2.name', 'Bug')
+                ->where('ticketLinkTypes.0.label', 'Relates to'),
             );
     }
 
@@ -208,4 +214,43 @@ class ProjectTicketMetadataSettingsControllerTest extends TestCase
             ->assertSessionHasErrors('field_type')
             ->assertRedirect(route('projects.settings.metadata', $project));
     }
+
+    /**
+     * Ensure users with edit permission can manage ticket link types.
+     */
+    public function test_users_with_edit_permission_can_manage_ticket_link_types(): void
+    {
+        $user = User::factory()->create();
+        $project = Project::factory()->create();
+        $ticketLinkType = TicketLinkType::factory()->for($project)->create([
+            'label' => 'Relates to',
+            'position' => 1,
+        ]);
+
+        app(ProjectPermissionService::class)->syncUserPermissions($project, $user, ['edit']);
+
+        $this->actingAs($user)
+            ->post(route('projects.settings.metadata.link-types.store', $project), [
+                'name' => 'Blocks',
+            ])
+            ->assertRedirect(route('projects.settings.metadata', $project))
+            ->assertSessionHas('status', 'Blocks link type was added.');
+
+        $this->actingAs($user)
+            ->patch(route('projects.settings.metadata.link-types.update', [$project, $ticketLinkType]), [
+                'name' => 'Depends on',
+                'position' => 2,
+            ])
+            ->assertRedirect(route('projects.settings.metadata', $project))
+            ->assertSessionHas('status', 'Depends on link type was updated.');
+
+        $this->actingAs($user)
+            ->delete(route('projects.settings.metadata.link-types.destroy', [$project, $ticketLinkType]))
+            ->assertRedirect(route('projects.settings.metadata', $project))
+            ->assertSessionHas('status', 'Depends on link type was removed.');
+
+        $this->assertDatabaseMissing('ticket_link_types', [
+            'id' => $ticketLinkType->id,
+        ]);
+    }
 }