app/Actions/Projects/UpdateProjectTemplate.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace App\Actions\Projects;
+
+use App\Models\ProjectTemplate;
+use Illuminate\Support\Arr;
+use Illuminate\Support\Facades\DB;
+
+class UpdateProjectTemplate
+{
+    public function __construct(
+        private readonly DuplicateProjectConfiguration $duplicateProjectConfiguration,
+    ) {}
+
+    /**
+     * @param  array{name: string, copy_areas?: array<int, string>}  $attributes
+     */
+    public function handle(ProjectTemplate $projectTemplate, array $attributes): ProjectTemplate
+    {
+        $projectTemplate->loadMissing('sourceProject', 'linkedProjects.projectTemplate');
+
+        $sourceProject = $projectTemplate->sourceProject;
+        abort_if($sourceProject === null, 422, 'This template cannot be edited because the source project is missing.');
+
+        $copyAreas = array_values(Arr::get($attributes, 'copy_areas', []));
+        $normalizedCopyAreas = $this->duplicateProjectConfiguration->normalizeCopyAreas($copyAreas);
+        $previousConfiguration = $projectTemplate->configuration_snapshot ?? [];
+        $nextConfiguration = $this->duplicateProjectConfiguration->export($sourceProject, $normalizedCopyAreas);
+        $affectedAreas = array_values(array_unique([
+            ...array_keys($previousConfiguration),
+            ...array_keys($nextConfiguration),
+        ]));
+
+        DB::transaction(function () use ($projectTemplate, $attributes, $normalizedCopyAreas, $nextConfiguration, $previousConfiguration, $affectedAreas): void {
+            $projectTemplate->forceFill([
+                'name' => $attributes['name'],
+                'copy_areas' => $normalizedCopyAreas,
+                'configuration_snapshot' => $nextConfiguration,
+            ])->save();
+
+            foreach ($projectTemplate->linkedProjects as $linkedProject) {
+                $currentConfiguration = $this->duplicateProjectConfiguration->export($linkedProject->fresh(), $affectedAreas);
+                $replacementConfiguration = [];
+
+                foreach ($nextConfiguration as $area => $configuration) {
+                    $isNewTemplateArea = ! array_key_exists($area, $previousConfiguration);
+                    $matchesPreviousTemplate = array_key_exists($area, $previousConfiguration)
+                        && array_key_exists($area, $currentConfiguration)
+                        && $currentConfiguration[$area] === $previousConfiguration[$area];
+
+                    if ($isNewTemplateArea || $matchesPreviousTemplate) {
+                        $replacementConfiguration[$area] = $configuration;
+                    }
+                }
+
+                if ($replacementConfiguration === []) {
+                    continue;
+                }
+
+                $this->duplicateProjectConfiguration->apply($linkedProject->fresh(), $replacementConfiguration);
+            }
+        });
+
+        return $projectTemplate->fresh(['sourceProject'])->loadCount('linkedProjects');
+    }
+}

app/Http/Controllers/ProjectTemplateController.php

@@ -4,7 +4,9 @@ namespace App\Http\Controllers;
 
 use App\Actions\Projects\CreateProjectTemplate;
 use App\Actions\Projects\DuplicateProjectConfiguration;
+use App\Actions\Projects\UpdateProjectTemplate;
 use App\Http\Requests\StoreProjectTemplateRequest;
+use App\Http\Requests\UpdateProjectTemplateRequest;
 use App\Http\Resources\ProjectResource;
 use App\Http\Resources\ProjectTemplateResource;
 use App\Models\Project;
@@ -18,6 +20,7 @@ class ProjectTemplateController extends Controller
 {
     public function __construct(
         private readonly CreateProjectTemplate $createProjectTemplate,
+        private readonly UpdateProjectTemplate $updateProjectTemplate,
     ) {}
 
     public function index(Request $request): Response
@@ -28,12 +31,25 @@ class ProjectTemplateController extends Controller
                 ProjectTemplate::query()
                     ->published()
                     ->with('sourceProject')
+                    ->withCount('linkedProjects')
                     ->orderBy('name')
                     ->get(),
             )->resolve(),
         ]);
     }
 
+    public function edit(ProjectTemplate $projectTemplate): Response
+    {
+        abort_if(! $projectTemplate->is_published, 404);
+
+        $projectTemplate->load('sourceProject')->loadCount('linkedProjects');
+
+        return Inertia::render('project-templates/Edit', [
+            'copyAreaOptions' => DuplicateProjectConfiguration::copyAreaOptions(),
+            'template' => ProjectTemplateResource::make($projectTemplate)->resolve(),
+        ]);
+    }
+
     public function create(Project $project): Response
     {
         return Inertia::render('project-templates/Create', [
@@ -50,6 +66,16 @@ class ProjectTemplateController extends Controller
             ->with('status', "Template {$template->name} was created.");
     }
 
+    public function update(UpdateProjectTemplateRequest $request, ProjectTemplate $projectTemplate): RedirectResponse
+    {
+        abort_if(! $projectTemplate->is_published, 404);
+
+        $template = $this->updateProjectTemplate->handle($projectTemplate, $request->validated());
+
+        return to_route('project-templates.index')
+            ->with('status', "Template {$template->name} was updated.");
+    }
+
     public function destroy(ProjectTemplate $projectTemplate): RedirectResponse
     {
         abort_if(! $projectTemplate->is_published, 404);

app/Http/Requests/UpdateProjectTemplateRequest.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace App\Http\Requests;
+
+use App\Actions\Projects\DuplicateProjectConfiguration;
+use App\Models\ProjectTemplate;
+use Illuminate\Contracts\Validation\ValidationRule;
+use Illuminate\Foundation\Http\FormRequest;
+use Illuminate\Validation\Rule;
+
+class UpdateProjectTemplateRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return $this->user()?->can('create-project') ?? false;
+    }
+
+    /**
+     * @return array<string, ValidationRule|array<mixed>|string>
+     */
+    public function rules(): array
+    {
+        /** @var ProjectTemplate|null $projectTemplate */
+        $projectTemplate = $this->route('projectTemplate');
+        $requiresImpactConfirmation = $projectTemplate?->linkedProjects()->exists() ?? false;
+
+        return [
+            'name' => ['required', 'string', 'max:255'],
+            'copy_areas' => ['required', 'array', 'min:1'],
+            'copy_areas.*' => ['string', Rule::in(DuplicateProjectConfiguration::copyableAreas())],
+            'confirm_linked_projects_update' => [
+                Rule::requiredIf($requiresImpactConfirmation),
+                'accepted',
+            ],
+        ];
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function messages(): array
+    {
+        return [
+            'confirm_linked_projects_update.accepted' => 'Acknowledge the linked project warning before saving template changes.',
+        ];
+    }
+}

app/Http/Resources/ProjectTemplateResource.php

@@ -29,6 +29,7 @@ class ProjectTemplateResource extends JsonResource
                 'is_published' => $this->is_published,
                 'copy_areas' => $this->copy_areas ?? [],
                 'configuration_snapshot' => $this->configuration_snapshot ?? [],
+                'linked_project_count' => $this->whenCounted('linkedProjects'),
                 'created_at' => $this->created_at?->toISOString(),
                 'updated_at' => $this->updated_at?->toISOString(),
             ];
@@ -44,6 +45,7 @@ class ProjectTemplateResource extends JsonResource
             'is_published' => Arr::get($this->resource, 'is_published', true),
             'copy_areas' => Arr::get($this->resource, 'copy_areas', []),
             'configuration_snapshot' => Arr::get($this->resource, 'configuration_snapshot', []),
+            'linked_project_count' => Arr::get($this->resource, 'linked_project_count'),
             'created_at' => Arr::get($this->resource, 'created_at'),
             'updated_at' => Arr::get($this->resource, 'updated_at'),
         ];

app/Models/ProjectTemplate.php

@@ -4,10 +4,11 @@ namespace App\Models;
 
 use Database\Factories\ProjectTemplateFactory;
 use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
-use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 
 #[Fillable(['project_id', 'source_project_id', 'name', 'slug', 'is_published', 'copy_areas', 'configuration_snapshot'])]
 class ProjectTemplate extends Model
@@ -38,4 +39,9 @@ class ProjectTemplate extends Model
     {
         return $this->belongsTo(Project::class, 'source_project_id');
     }
+
+    public function linkedProjects(): HasMany
+    {
+        return $this->hasMany(Project::class, 'project_template_id');
+    }
 }

resources/js/pages/project-templates/Edit.vue

@@ -0,0 +1,171 @@
+<script setup lang="ts">
+import { Head, Link, useForm } from '@inertiajs/vue3';
+import { computed } from 'vue';
+import Heading from '@/components/Heading.vue';
+import InputError from '@/components/InputError.vue';
+import { Badge } from '@/components/ui/badge';
+import { Button } from '@/components/ui/button';
+import {
+    Card,
+    CardContent,
+    CardDescription,
+    CardHeader,
+    CardTitle,
+} from '@/components/ui/card';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import AppLayout from '@/layouts/AppLayout.vue';
+import { index as projectTemplatesIndex } from '@/routes/project-templates';
+import type { BreadcrumbItem, ProjectTemplatesEditPageProps } from '@/types';
+
+const props = defineProps<ProjectTemplatesEditPageProps>();
+
+const breadcrumbs: BreadcrumbItem[] = [
+    {
+        title: 'Project templates',
+        href: projectTemplatesIndex(),
+    },
+    {
+        title: props.template.name,
+        href: `/project-templates/${props.template.id}/edit`,
+    },
+];
+
+const form = useForm({
+    confirm_linked_projects_update: false,
+    copy_areas: [...props.template.copy_areas],
+    name: props.template.name,
+});
+
+const copyAreasError = computed(() => {
+    return (
+        form.errors.copy_areas ??
+        Object.entries(form.errors).find(([key]) => key.startsWith('copy_areas.'))?.[1] ??
+        ''
+    );
+});
+
+const linkedProjectCount = computed(() => props.template.linked_project_count ?? 0);
+
+const submit = (): void => {
+    form.patch(`/project-templates/${props.template.id}`, {
+        preserveScroll: true,
+    });
+};
+</script>
+
+<template>
+    <AppLayout :breadcrumbs="breadcrumbs">
+        <Head :title="`Edit ${template.name}`" />
+
+        <div class="mx-auto flex w-full max-w-3xl flex-1 flex-col gap-6 p-4">
+            <div class="space-y-3">
+                <div class="flex flex-wrap items-center gap-3">
+                    <Badge variant="outline" class="px-3 py-1">{{ template.slug }}</Badge>
+                    <Badge v-if="linkedProjectCount > 0" variant="secondary">
+                        {{ linkedProjectCount }} linked {{ linkedProjectCount === 1 ? 'project' : 'projects' }}
+                    </Badge>
+                </div>
+                <Heading
+                    :title="`Edit ${template.name}`"
+                    description="Refresh the template baseline from its source project while keeping immutable identifiers protected."
+                />
+            </div>
+
+            <Card>
+                <CardHeader>
+                    <CardTitle>Template details</CardTitle>
+                    <CardDescription>
+                        <template v-if="template.source_project">
+                            This template baseline is rebuilt from {{ template.source_project.name }} ({{ template.source_project.key }}) when you save.
+                        </template>
+                        <template v-else>
+                            This template baseline is rebuilt from its source project when you save.
+                        </template>
+                    </CardDescription>
+                </CardHeader>
+
+                <CardContent>
+                    <form class="space-y-6" @submit.prevent="submit">
+                        <div class="grid gap-2">
+                            <Label for="name">Template name</Label>
+                            <Input id="name" v-model="form.name" required placeholder="Foundation template" />
+                            <InputError :message="form.errors.name" />
+                        </div>
+
+                        <div class="grid gap-2">
+                            <Label for="slug">Template slug</Label>
+                            <Input id="slug" :model-value="template.slug" disabled />
+                            <p class="text-muted-foreground text-sm">
+                                The slug stays locked so existing template references remain stable.
+                            </p>
+                        </div>
+
+                        <div class="grid gap-3">
+                            <div>
+                                <Label>Configuration groups</Label>
+                                <p class="text-muted-foreground text-sm">
+                                    Saving rebuilds the selected groups from the current source-project configuration.
+                                </p>
+                            </div>
+
+                            <div class="grid gap-3">
+                                <Label
+                                    v-for="copyAreaOption in copyAreaOptions"
+                                    :key="copyAreaOption.value"
+                                    class="flex cursor-pointer items-start gap-3 rounded-xl border p-4"
+                                >
+                                    <input
+                                        v-model="form.copy_areas"
+                                        type="checkbox"
+                                        :value="copyAreaOption.value"
+                                        class="mt-1"
+                                    />
+                                    <div class="space-y-1">
+                                        <div class="font-medium">{{ copyAreaOption.label }}</div>
+                                        <p class="text-muted-foreground text-sm">
+                                            {{ copyAreaOption.description }}
+                                        </p>
+                                    </div>
+                                </Label>
+                            </div>
+                            <InputError :message="copyAreasError" />
+                        </div>
+
+                        <div
+                            v-if="linkedProjectCount > 0"
+                            class="space-y-3 rounded-xl border border-amber-300 bg-amber-50 p-4 text-amber-950 dark:border-amber-900/70 dark:bg-amber-950/40 dark:text-amber-100"
+                        >
+                            <div class="space-y-1">
+                                <div class="font-medium">Warning</div>
+                                <p class="text-sm">
+                                    Saving this template updates the baseline for {{ linkedProjectCount }} linked {{ linkedProjectCount === 1 ? 'project' : 'projects' }}.
+                                    Inherited areas will follow the new template version, while existing overrides stay untouched.
+                                </p>
+                            </div>
+
+                            <Label class="flex cursor-pointer items-start gap-3">
+                                <input v-model="form.confirm_linked_projects_update" type="checkbox" class="mt-1" />
+                                <span class="text-sm">
+                                    I understand that linked projects inheriting from this template will be affected.
+                                </span>
+                            </Label>
+
+                            <InputError :message="form.errors.confirm_linked_projects_update" />
+                        </div>
+
+                        <div class="flex items-center gap-3">
+                            <Button type="submit" :disabled="form.processing">
+                                Save template changes
+                            </Button>
+
+                            <Button as-child variant="outline">
+                                <Link :href="projectTemplatesIndex()">Cancel</Link>
+                            </Button>
+                        </div>
+                    </form>
+                </CardContent>
+            </Card>
+        </div>
+    </AppLayout>
+</template>

resources/js/pages/project-templates/Index.vue

@@ -11,6 +11,7 @@ import {
     CardTitle,
 } from '@/components/ui/card';
 import AppLayout from '@/layouts/AppLayout.vue';
+import { edit as projectTemplatesEdit } from '@/routes/project-templates';
 import { create as projectsCreate, index as projectsIndex } from '@/routes/projects/index';
 import type { BreadcrumbItem, ProjectTemplatesIndexPageProps } from '@/types';
 
@@ -69,6 +70,9 @@ const removeTemplate = (templateId: number): void => {
                         <div class="flex flex-wrap items-center gap-2">
                             <CardTitle>{{ template.name }}</CardTitle>
                             <Badge variant="secondary">{{ template.slug }}</Badge>
+                            <Badge v-if="template.linked_project_count" variant="outline">
+                                {{ template.linked_project_count }} linked {{ template.linked_project_count === 1 ? 'project' : 'projects' }}
+                            </Badge>
                         </div>
                         <CardDescription>
                             <template v-if="template.source_project">
@@ -91,6 +95,12 @@ const removeTemplate = (templateId: number): void => {
                         </div>
 
                         <div class="flex flex-wrap gap-3">
+                            <Button as-child variant="secondary">
+                                <Link :href="projectTemplatesEdit(template.id)">
+                                    Edit
+                                </Link>
+                            </Button>
+
                             <Button as-child variant="outline">
                                 <Link :href="projectsCreate({ query: { template: template.id } })">
                                     Use template

resources/js/types/models/project-template-model.ts

@@ -10,6 +10,7 @@ export type ProjectTemplateModel = {
     slug: string;
     copy_areas: string[];
     configuration_snapshot: Record<string, unknown>;
+    linked_project_count?: number;
     created_at: string | null;
     updated_at: string | null;
 };

resources/js/types/page-props.ts

@@ -61,6 +61,11 @@ export type ProjectTemplatesCreatePageProps = {
     project: ProjectModel;
 };
 
+export type ProjectTemplatesEditPageProps = {
+    copyAreaOptions: ProjectDuplicateCopyAreaOption[];
+    template: ProjectTemplateModel;
+};
+
 export type ProjectTemplateStateArea = {
     label: string;
     value: string;

routes/web/project-templates.php

@@ -8,5 +8,7 @@ Route::middleware('can:create-project')
     ->name('project-templates.')
     ->group(function (): void {
         Route::get('/', [ProjectTemplateController::class, 'index'])->name('index');
+        Route::get('{projectTemplate}/edit', [ProjectTemplateController::class, 'edit'])->name('edit');
+        Route::patch('{projectTemplate}', [ProjectTemplateController::class, 'update'])->name('update');
         Route::delete('{projectTemplate}', [ProjectTemplateController::class, 'destroy'])->name('destroy');
     });

tests/Feature/Projects/ProjectTemplateControllerTest.php

@@ -57,6 +57,15 @@ class ProjectTemplateControllerTest extends TestCase
                 ->component('project-templates/Create')
                 ->where('project.id', $project->id)
                 ->has('copyAreaOptions', count(DuplicateProjectConfiguration::copyableAreas())));
+
+        $this->actingAs($user)
+            ->get(route('project-templates.edit', $template))
+            ->assertOk()
+            ->assertInertia(fn (Assert $page) => $page
+                ->component('project-templates/Edit')
+                ->where('template.id', $template->id)
+                ->where('template.slug', 'foundation-template')
+                ->has('copyAreaOptions', count(DuplicateProjectConfiguration::copyableAreas())));
     }
 
     public function test_users_can_save_and_delete_templates_from_projects(): void
@@ -148,5 +157,97 @@ class ProjectTemplateControllerTest extends TestCase
         $this->actingAs($user)
             ->delete(route('project-templates.destroy', $template))
             ->assertNotFound();
+
+        $this->actingAs($user)
+            ->get(route('project-templates.edit', $template))
+            ->assertNotFound();
+    }
+
+    public function test_updating_a_template_requires_warning_acknowledgement_when_projects_are_linked(): void
+    {
+        $user = User::factory()->create();
+        $sourceProject = Project::factory()->create();
+        $template = ProjectTemplate::factory()->create([
+            'source_project_id' => $sourceProject->id,
+        ]);
+        Project::factory()->create([
+            'project_template_id' => $template->id,
+        ]);
+
+        $this->syncGlobalPermissions($user, ['project:create']);
+
+        $this->actingAs($user)
+            ->patch(route('project-templates.update', $template), [
+                'name' => 'Updated Template',
+                'copy_areas' => [DuplicateProjectConfiguration::COPY_PROJECT_SETTINGS],
+            ])
+            ->assertSessionHasErrors('confirm_linked_projects_update');
+    }
+
+    public function test_updating_a_template_refreshes_the_baseline_and_preserves_slug_and_overrides(): void
+    {
+        $user = User::factory()->create();
+        $sourceProject = Project::factory()->create([
+            'name' => 'Template Source',
+            'show_author' => false,
+            'show_story_points' => false,
+        ]);
+        $template = ProjectTemplate::factory()->create([
+            'name' => 'Platform Template',
+            'slug' => 'platform-template',
+            'copy_areas' => [DuplicateProjectConfiguration::COPY_PROJECT_SETTINGS],
+            'configuration_snapshot' => [
+                DuplicateProjectConfiguration::COPY_PROJECT_SETTINGS => [
+                    'show_author' => false,
+                    'show_story_points' => false,
+                ],
+            ],
+            'source_project_id' => $sourceProject->id,
+        ]);
+        $inheritingProject = Project::factory()->create([
+            'project_template_id' => $template->id,
+            'show_author' => false,
+            'show_story_points' => false,
+        ]);
+        $overriddenProject = Project::factory()->create([
+            'project_template_id' => $template->id,
+            'show_author' => true,
+            'show_story_points' => false,
+        ]);
+
+        $sourceProject->forceFill([
+            'show_author' => true,
+            'show_story_points' => true,
+        ])->save();
+
+        $this->syncGlobalPermissions($user, ['project:create']);
+
+        $this->actingAs($user)
+            ->patch(route('project-templates.update', $template), [
+                'name' => 'Platform Template v2',
+                'slug' => 'should-not-change',
+                'copy_areas' => [DuplicateProjectConfiguration::COPY_PROJECT_SETTINGS],
+                'confirm_linked_projects_update' => true,
+            ])
+            ->assertRedirect('/project-templates');
+
+        $template->refresh();
+        $inheritingProject->refresh();
+        $overriddenProject->refresh();
+
+        $this->assertSame('Platform Template v2', $template->name);
+        $this->assertSame('platform-template', $template->slug);
+        $this->assertSame([
+            DuplicateProjectConfiguration::COPY_PROJECT_SETTINGS => [
+                'show_author' => true,
+                'show_story_points' => true,
+            ],
+        ], $template->configuration_snapshot);
+
+        $this->assertTrue($inheritingProject->show_author);
+        $this->assertTrue($inheritingProject->show_story_points);
+
+        $this->assertTrue($overriddenProject->show_author);
+        $this->assertFalse($overriddenProject->show_story_points);
     }
 }