From 0975b2f69ba7d95e9501f82e1452e65a059beedf Mon Sep 17 00:00:00 2001
From: Jan-Niclas Loosen <janniclas@loosen-it.de>
Date: Sun, 27 Sep 2026 16:28:27 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20lit/tb-assign=20=E2=80=93=20conditions?=
 =?UTF-8?q?=20with=20dry=20run=20on=20live=20templates,=20reattach?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- ThemeBuilderAccess::changeableTemplate(): rights (Q18 not_found), group gate,
  no TB draft, never the default template, current template_rev
- omitted exclude_from stays, [] clears (Q3); live dry run shows use_on and
  exclude_from before/after, overlaps and possible overlaps (B9)
- reattach only with published layouts (B10) and a live TB post; always
  disabled, unmarks template and layouts; failure restores everything

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
---
 .../Divi/ThemeBuilder/TbAssignAbility.php     | 329 ++++++++++++++++++
 .../Divi/ThemeBuilder/Template.php            |  69 ++++
 .../Divi/ThemeBuilder/ThemeBuilderAccess.php  |  55 +++
 .../ThemeBuilder/ThemeBuilderIntegration.php  |   1 +
 .../Integrations/Divi/DiviIntegrationTest.php |   2 +-
 .../Divi/ThemeBuilder/TbAssignAbilityTest.php | 309 ++++++++++++++++
 .../Divi/ThemeBuilder/TemplateTest.php        |  37 ++
 .../ThemeBuilder/ThemeBuilderAccessTest.php   |  36 ++
 8 files changed, 837 insertions(+), 1 deletion(-)
 create mode 100644 src/Integrations/Divi/ThemeBuilder/TbAssignAbility.php
 create mode 100644 tests/Unit/Integrations/Divi/ThemeBuilder/TbAssignAbilityTest.php

diff --git a/src/Integrations/Divi/ThemeBuilder/TbAssignAbility.php b/src/Integrations/Divi/ThemeBuilder/TbAssignAbility.php
new file mode 100644
index 0000000..5f3843b
--- /dev/null
+++ b/src/Integrations/Divi/ThemeBuilder/TbAssignAbility.php
@@ -0,0 +1,329 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\ThemeBuilder;
+
+use LIT\MCP\Abilities\Ability;
+use LIT\MCP\Abilities\Annotations;
+use LIT\MCP\Abilities\Errors;
+use LIT\MCP\Abilities\FollowUp;
+use LIT\MCP\Abilities\Rollback;
+use LIT\MCP\Abilities\ToolResult;
+use LIT\MCP\Abilities\WriteFailed;
+use LIT\MCP\ChangeLog\ChangeLog;
+use Throwable;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+/**
+ * lit/tb-assign (spec §5.7): replaces the conditions of a template (_et_use_on/_et_exclude_from, only from
+ * TemplateConditions). use_on is required; an omitted exclude_from stays as it is, an explicit [] clears it
+ * (ruling Q3/B3). A live template changes the website at once, so it is a dry run first and needs confirm: true
+ * (ruling Q9/B22), listing both lists before/after and overlaps (identical and possible, B9) with other live
+ * templates for the resulting lists. reattach: true puts a template a stale Theme Builder save removed back on the
+ * live list (only on the user's request, B19) – always disabled, Divi's "unused" marks removed from it and its
+ * layouts, which must still be published (B10). Templates have no revisions: the previous conditions are in the
+ * answer and the change log; a failed write restores them (and undoes the reattach).
+ */
+final class TbAssignAbility implements Ability
+{
+    public const REASON = 'Die Bedingungen der Vorlage konnten nicht gespeichert werden.';
+
+    public function __construct(
+        private ThemeBuilderAccess $access,
+        private TemplateConditions $conditions,
+        private ChangeLog $log
+    ) {
+    }
+
+    public function name(): string
+    {
+        return 'lit/tb-assign';
+    }
+
+    public function label(): string
+    {
+        return 'Theme-Builder-Vorlage zuordnen';
+    }
+
+    public function description(): string
+    {
+        return 'Setzt die Bedingungen einer Theme-Builder-Vorlage neu: use_on ersetzt die bisherigen (z. B. '
+            . '"singular:post_type:person:all" = alle Einträge des Inhaltstyps person), exclude_from ebenso – fehlt '
+            . 'exclude_from, bleiben die Ausnahmen, [] entfernt sie. IDs aus lit/tb-list mit conditions: true; '
+            . 'template_rev aus lit/tb-list ist Pflicht. Bei einer aktiven Vorlage wirkt das sofort auf der Website: '
+            . 'erst Probelauf (vorher/nachher, Überschneidungen), dann nach Rückfrage beim Nutzer confirm: true. '
+            . 'reattach: true ordnet eine Vorlage wieder zu, die ein Speichern im Theme Builder entfernt hat (nur auf '
+            . 'ausdrücklichen Wunsch des Nutzers; sie bleibt deaktiviert). Die Standardvorlage nur im Theme Builder.';
+    }
+
+    public function inputSchema(): array
+    {
+        $conditions = ['type' => 'array', 'maxItems' => TemplateConditions::MAX, 'items' => ['type' => 'string']];
+
+        return [
+            'type' => 'object',
+            'properties' => [
+                'template_id' => ['type' => 'integer', 'minimum' => 1],
+                'template_rev' => ['type' => 'string', 'description' => 'template_rev aus lit/tb-list.'],
+                'use_on' => $conditions,
+                'exclude_from' => $conditions + [
+                    'description' => 'Fehlt es, bleiben die bisherigen Ausnahmen; [] entfernt sie.',
+                ],
+                'reattach' => ['type' => 'boolean'],
+                'confirm' => ['type' => 'boolean'],
+            ],
+            'required' => ['template_id', 'template_rev', 'use_on'],
+            'additionalProperties' => false,
+        ];
+    }
+
+    public function outputSchema(): ?array
+    {
+        return ToolResult::schema([
+            'template_id' => ['type' => 'integer'],
+            'template_rev' => ['type' => 'string'],
+            'live' => ['type' => 'boolean'],
+            'previous' => ['type' => 'object'],
+        ], ['template_id', 'template_rev', 'live']);
+    }
+
+    public function annotations(): array
+    {
+        return Annotations::destructive(true);
+    }
+
+    public function isDirect(): bool
+    {
+        return false;
+    }
+
+    public function permission(array $input): bool|WP_Error
+    {
+        $template = $this->access->changeableTemplate($input);
+
+        return $template instanceof WP_Error ? $template : true;
+    }
+
+    /** @throws WriteFailed */
+    public function execute(array $input): mixed
+    {
+        $template = $this->access->changeableTemplate($input);
+        if ($template instanceof WP_Error) {
+            return $template;
+        }
+
+        $useOn = is_array($input['use_on'] ?? null)
+            ? $this->conditions->check($input['use_on'], 'use_on')
+            : ['ids' => [], 'errors' => ['use_on' => 'Liste von Bedingungs-IDs erwartet (leere Liste = keine)']];
+        $excludeFrom = array_key_exists('exclude_from', $input)
+            ? $this->conditions->check($input['exclude_from'] ?? [], 'exclude_from')
+            : ['ids' => $template->excludeFrom, 'errors' => []];
+        $errors = array_merge($useOn['errors'], $excludeFrom['errors']);
+        if ($errors !== []) {
+            return Errors::invalidInput('Bedingungen sind ungültig; nichts wurde gespeichert.', $errors);
+        }
+
+        $reattach = ! $template->attached && ($input['reattach'] ?? false) === true;
+        $refusal = $this->reattachRefusal($template, $reattach);
+        if ($refusal !== null) {
+            return $refusal;
+        }
+
+        if ($template->isLive() && ($input['confirm'] ?? false) !== true) {
+            return $this->dryRun($template, $useOn['ids'], $excludeFrom['ids']);
+        }
+
+        return $this->write($template, $useOn['ids'], $excludeFrom['ids'], $reattach);
+    }
+
+    /** A detached template needs reattach: true, a live Theme Builder post and published layouts (B10). */
+    private function reattachRefusal(Template $template, bool $reattach): ?WP_Error
+    {
+        if ($template->attached) {
+            return null;
+        }
+
+        if (! $reattach) {
+            $marked = $template->markedUnused === null
+                ? ''
+                : sprintf(' (seit %s als ungenutzt markiert; Divi löscht sie 7 Tage danach)', $template->markedUnused);
+
+            return Errors::invalidInput(
+                sprintf(
+                    'Vorlage %d ist im Theme Builder nicht mehr zugeordnet%s; nichts wurde gespeichert.',
+                    $template->id,
+                    $marked
+                ),
+                [
+                    'reattach' => 'nur auf Wunsch des Nutzers mit reattach: true wieder zuordnen (die Vorlage bleibt '
+                        . 'deaktiviert)',
+                ]
+            );
+        }
+
+        if ($this->access->store()->liveId() <= 0) {
+            return Errors::unsupported(
+                'Der Divi Theme Builder wurde noch nie gespeichert; es gibt keine Liste, der die Vorlage wieder '
+                    . 'zugeordnet werden kann. Nichts wurde gespeichert.',
+                'Den Theme Builder einmal speichern (Divi → Theme Builder), dann erneut aufrufen.'
+            );
+        }
+
+        return $this->access->layoutsRefusal($template);
+    }
+
+    /**
+     * @param list<string> $useOn
+     * @param list<string> $excludeFrom
+     */
+    private function dryRun(Template $template, array $useOn, array $excludeFrom): WP_Error
+    {
+        $live = $this->access->store()->liveTemplates();
+
+        return Errors::confirmRequired(
+            sprintf(
+                'Vorlage „%s“ ist aktiv; die neuen Bedingungen (use_on) und Ausnahmen (exclude_from) wirken sofort auf '
+                    . 'der Website – vorher/nachher unter before/after. Nichts wurde gespeichert (Probelauf).',
+                $template->title
+            ),
+            [
+                'before' => $this->labels($template->useOn, $template->excludeFrom),
+                'after' => $this->labels($useOn, $excludeFrom),
+                'overlaps' => Template::overlaps($live, $template->id, $useOn),
+                'possible_overlaps' => Template::possibleOverlaps($live, $template->id, $useOn),
+            ]
+        );
+    }
+
+    /**
+     * @param list<string> $useOn
+     * @param list<string> $excludeFrom
+     * @return array{use_on: list<string>, exclude_from: list<string>}
+     */
+    private function labels(array $useOn, array $excludeFrom): array
+    {
+        return [
+            'use_on' => array_map($this->conditions->label(...), $useOn),
+            'exclude_from' => array_map($this->conditions->label(...), $excludeFrom),
+        ];
+    }
+
+    /**
+     * @param list<string> $useOn
+     * @param list<string> $excludeFrom
+     * @return array<string, mixed>
+     * @throws WriteFailed
+     */
+    private function write(Template $template, array $useOn, array $excludeFrom, bool $reattach): array
+    {
+        $store = $this->access->store();
+        $themeBuilderId = $store->liveId();
+        try {
+            if ($reattach) {
+                $store->setEnabled($template->id, false);
+                $store->attach($themeBuilderId, $template->id);
+                foreach (array_merge([$template->id], array_column($template->layouts, 'id')) as $id) {
+                    if ($id > 0) {
+                        $store->unmarkUnused($id);
+                    }
+                }
+            }
+            $store->setConditions($template->id, $useOn, $excludeFrom);
+        } catch (Throwable $e) {
+            $this->undo($template, $reattach, $themeBuilderId, $e);
+        }
+
+        $warnings = [];
+        if ($template->isLive()) {
+            FollowUp::run(
+                static fn () => $store->clearCaches(),
+                'theme builder cache',
+                'Der Cache des Theme Builders konnte nicht geleert werden; die Bedingungen sind gespeichert, wirken '
+                    . 'aber evtl. erst nach „Statische CSS-Dateien leeren“ (Divi → Theme-Optionen → Builder).',
+                $warnings
+            );
+        }
+        if ($reattach) {
+            $warnings[] = TbCreateTemplateAbility::STALE_EDITOR;
+        }
+        $logId = $this->log->record(
+            $this->name(),
+            DiviThemeBuilder::TEMPLATE,
+            (string) $template->id,
+            sprintf(
+                'Theme Builder: Bedingungen von „%s“ gesetzt%s (vorher: %s; Ausnahmen vorher: %s)',
+                $template->title,
+                $reattach ? ', wieder zugeordnet (deaktiviert)' : '',
+                self::listed($template->useOn),
+                self::listed($template->excludeFrom)
+            )
+        );
+        $after = $store->template($template->id, $template->attached || $reattach);
+        $live = $after?->isLive() ?? false;
+
+        return ToolResult::ok(sprintf(
+            'Bedingungen der Vorlage „%s“ gesetzt%s%s.',
+            $template->title,
+            $reattach ? ' und wieder zugeordnet' : '',
+            $live
+                ? ' – wirkt sofort auf der Website; zurück mit lit/tb-assign und den Bedingungen unter previous, '
+                    . 'ausblenden mit lit/tb-activate (enabled: false)'
+                : ' (Vorlage deaktiviert, ohne Wirkung auf die Website)'
+        ))
+            ->with('template_id', $template->id)
+            ->with('template_rev', $after?->rev() ?? '')
+            ->with('live', $live)
+            ->with('previous', ['use_on' => $template->useOn, 'exclude_from' => $template->excludeFrom])
+            ->warnings($warnings)
+            ->logId($logId)
+            ->urls(null, (string) admin_url('admin.php?page=et_theme_builder'))
+            ->toArray();
+    }
+
+    /** @param list<string> $conditions */
+    private static function listed(array $conditions): string
+    {
+        return $conditions === [] ? 'keine' : implode(', ', $conditions);
+    }
+
+    /** @throws WriteFailed Always. */
+    private function undo(Template $template, bool $reattach, int $themeBuilderId, Throwable $cause): never
+    {
+        $store = $this->access->store();
+        $steps = [static fn () => $store->setConditions($template->id, $template->useOn, $template->excludeFrom)];
+        if ($reattach) {
+            $steps[] = static fn () => $store->detach($themeBuilderId, $template->id);
+            $steps[] = static fn () => $store->setEnabled($template->id, $template->enabled);
+        }
+
+        $failures = Rollback::attempt(...$steps);
+        if ($failures === []) {
+            throw WriteFailed::rolledBack(self::REASON, $cause, 'tb-assign failed: ' . $cause->getMessage());
+        }
+
+        $this->log->recordPartial(
+            $this->name(),
+            DiviThemeBuilder::TEMPLATE,
+            (string) $template->id,
+            sprintf(
+                'Theme Builder: Bedingungen von „%s“ nur teilweise zurückgenommen (%s)',
+                $template->title,
+                implode('; ', $failures)
+            )
+        );
+        throw WriteFailed::partial(
+            self::REASON,
+            $cause,
+            'tb-assign rollback: ' . implode('; ', $failures),
+            $template->id,
+            hint: sprintf(
+                'Mit lit/tb-list prüfen; vorher galt: %s; Ausnahmen: %s.',
+                self::listed($template->useOn),
+                self::listed($template->excludeFrom)
+            )
+        );
+    }
+}
diff --git a/src/Integrations/Divi/ThemeBuilder/Template.php b/src/Integrations/Divi/ThemeBuilder/Template.php
index d303804..2afd138 100644
--- a/src/Integrations/Divi/ThemeBuilder/Template.php
+++ b/src/Integrations/Divi/ThemeBuilder/Template.php
@@ -145,6 +145,75 @@ final class Template
         return $overlaps;
     }
 
+    /**
+     * Live templates other than $exceptId whose conditions are not identical to one of $useOn but may cover
+     * the same pages (ruling Q8/B9 – "kann sich überschneiden"): same family, e.g. all pages vs. one page,
+     * all archives vs. one category archive, posts in a category vs. any single post, the front page vs. pages.
+     * Deliberately generous – the dry run is the user's only preview. Identical conditions are overlaps().
+     *
+     * @param list<Template> $live
+     * @param list<string>   $useOn
+     * @return list<array{id: int, title: string, conditions: list<string>}>
+     */
+    public static function possibleOverlaps(array $live, int $exceptId, array $useOn): array
+    {
+        $overlaps = [];
+        foreach ($live as $other) {
+            if ($other->id === $exceptId || ! $other->isLive()) {
+                continue;
+            }
+            $conditions = [];
+            foreach ($other->useOn as $theirs) {
+                foreach ($useOn as $ours) {
+                    if ($theirs !== $ours && self::mayOverlap($theirs, $ours)) {
+                        $conditions[] = $theirs;
+                        break;
+                    }
+                }
+            }
+            if ($conditions !== []) {
+                $overlaps[] = ['id' => $other->id, 'title' => $other->title, 'conditions' => $conditions];
+            }
+        }
+
+        return $overlaps;
+    }
+
+    private static function mayOverlap(string $a, string $b): bool
+    {
+        foreach (self::scopesOf($a) as $x) {
+            foreach (self::scopesOf($b) as $y) {
+                if ($x === $y || str_starts_with($x, $y . ':') || str_starts_with($y, $x . ':')) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * The page families a condition covers (Divi's IDs, theme-builder.php:689-1060): singular:post_type:<type>,
+     * archive:taxonomy:<taxonomy>, archive:post_type:<type>, archive:user, archive:date; "<kind>:all" and posts
+     * in a term (singular:taxonomy:…) the whole kind; the front page may be a page or the posts archive.
+     *
+     * @return list<string>
+     */
+    private static function scopesOf(string $condition): array
+    {
+        if ($condition === 'homepage') {
+            return ['homepage', 'singular:post_type:page', 'archive:post_type:post'];
+        }
+
+        $parts = explode(':', $condition);
+        $second = $parts[1] ?? '';
+        if (($parts[0] === 'singular' && $second === 'taxonomy') || $second === 'all') {
+            return [$parts[0]];
+        }
+
+        return [implode(':', array_slice($parts, 0, in_array($second, ['post_type', 'taxonomy'], true) ? 3 : 2))];
+    }
+
     /** @return list<string> */
     private static function strings(mixed $list): array
     {
diff --git a/src/Integrations/Divi/ThemeBuilder/ThemeBuilderAccess.php b/src/Integrations/Divi/ThemeBuilder/ThemeBuilderAccess.php
index 03bf700..23bf484 100644
--- a/src/Integrations/Divi/ThemeBuilder/ThemeBuilderAccess.php
+++ b/src/Integrations/Divi/ThemeBuilder/ThemeBuilderAccess.php
@@ -154,6 +154,23 @@ class ThemeBuilderAccess
         return $forWrite ? ($this->writableGate() ?? $post) : $post;
     }
 
+    /**
+     * A template the Theme Builder tools may change (lit/tb-assign, lit/tb-activate): rights and group gate
+     * (template(), a template the user may not edit reads as missing – ruling Q18), no Theme Builder draft (E7),
+     * never the default template (E8), the current template_rev.
+     *
+     * @param array<string, mixed> $input template_id, template_rev
+     */
+    public function changeableTemplate(array $input): Template|WP_Error
+    {
+        $post = $this->template($input['template_id'] ?? null, true);
+        if ($post instanceof WP_Error) {
+            return $post;
+        }
+
+        return $this->checkedTemplate((int) $post->ID, $input);
+    }
+
     /**
      * Whether template $id may be named to this user (tb-list shows other IDs not at all, ruling Q8/B11).
      * $id must come from Divi's own template list (templateIds()/liveTemplates()/detachedIds()): this checks
@@ -244,4 +261,42 @@ class ThemeBuilderAccess
             'Im Theme Builder (Divi → Theme Builder) speichern oder die Änderungen verwerfen, dann erneut aufrufen.'
         );
     }
+
+    /**
+     * The draft, default and template_rev checks of changeableTemplate() for template $id (rights already checked).
+     *
+     * @param array<string, mixed> $input
+     */
+    private function checkedTemplate(int $id, array $input): Template|WP_Error
+    {
+        $refusal = $this->draftRefusal();
+        if ($refusal !== null) {
+            return $refusal;
+        }
+
+        $attached = in_array($id, $this->store->templateIds($this->store->liveId()), true);
+        $template = $this->store->template($id, $attached);
+        if ($template === null) {
+            return Errors::notFound(
+                sprintf('Theme-Builder-Vorlage %d gibt es nicht.', $id),
+                'Vorlagen mit lit/tb-list auflisten.'
+            );
+        }
+
+        if ($template->default) {
+            return Errors::unsupported(
+                'Die Standardvorlage ändert LIT MCP nicht; nichts wurde gespeichert.',
+                'Die Standardvorlage im Divi Theme Builder bearbeiten.'
+            );
+        }
+
+        if (! is_string($input['template_rev'] ?? null) || $input['template_rev'] !== $template->rev()) {
+            return Errors::revMismatch(
+                'Die Vorlage wurde seit dem Lesen geändert (template_rev passt nicht); nichts wurde gespeichert.',
+                'Mit lit/tb-list neu lesen und mit der neuen template_rev wiederholen.'
+            );
+        }
+
+        return $template;
+    }
 }
diff --git a/src/Integrations/Divi/ThemeBuilder/ThemeBuilderIntegration.php b/src/Integrations/Divi/ThemeBuilder/ThemeBuilderIntegration.php
index ef4a222..8c4439b 100644
--- a/src/Integrations/Divi/ThemeBuilder/ThemeBuilderIntegration.php
+++ b/src/Integrations/Divi/ThemeBuilder/ThemeBuilderIntegration.php
@@ -52,6 +52,7 @@ final class ThemeBuilderIntegration implements Integration
         return [
             new TbListAbility($this->access, $conditions),
             new TbCreateTemplateAbility($this->access, $conditions, $this->composition, $this->saver, $this->log),
+            new TbAssignAbility($this->access, $conditions, $this->log),
         ];
     }
 }
diff --git a/tests/Unit/Integrations/Divi/DiviIntegrationTest.php b/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
index 2f76381..4de492e 100644
--- a/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
+++ b/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
@@ -78,7 +78,7 @@ final class DiviIntegrationTest extends TestCase
         self::assertSame('Divi Theme Builder', $group->label());
         self::assertFalse($group->isAvailable(), 'no Divi classes in unit tests');
         self::assertSame(
-            ['lit/tb-list', 'lit/tb-create-template'],
+            ['lit/tb-list', 'lit/tb-create-template', 'lit/tb-assign'],
             array_map(static fn (Ability $ability): string => $ability->name(), $group->abilities())
         );
         foreach ($group->abilities() as $ability) {
diff --git a/tests/Unit/Integrations/Divi/ThemeBuilder/TbAssignAbilityTest.php b/tests/Unit/Integrations/Divi/ThemeBuilder/TbAssignAbilityTest.php
new file mode 100644
index 0000000..c735bc2
--- /dev/null
+++ b/tests/Unit/Integrations/Divi/ThemeBuilder/TbAssignAbilityTest.php
@@ -0,0 +1,309 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit\Integrations\Divi\ThemeBuilder;
+
+use Brain\Monkey\Functions;
+use LIT\MCP\Abilities\WriteFailed;
+use LIT\MCP\Integrations\Divi\ThemeBuilder\DiviThemeBuilder;
+use LIT\MCP\Integrations\Divi\ThemeBuilder\TbAssignAbility;
+use LIT\MCP\Integrations\Divi\ThemeBuilder\Template;
+use LIT\MCP\Integrations\Divi\ThemeBuilder\TemplateConditions;
+use LIT\MCP\Tests\Support\DiviWriterFixture;
+use LIT\MCP\Tests\Support\FakeChangeLog;
+use LIT\MCP\Tests\Support\LibraryFixtures;
+use LIT\MCP\Tests\Support\ThemeBuilderFixtures;
+use LIT\MCP\Tests\Unit\TestCase;
+use RuntimeException;
+
+final class TbAssignAbilityTest extends TestCase
+{
+    private const PERSONS = 'singular:post_type:lit_person:all';
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        self::givenPosts();
+        Functions\when('admin_url')->alias(static fn (string $path): string => 'https://kunde.test/wp-admin/' . $path);
+    }
+
+    /** @param array<string, mixed> $bodyFields */
+    private static function givenPosts(array $bodyFields = []): void
+    {
+        LibraryFixtures::given([
+            ThemeBuilderFixtures::templatePost(1066),
+            ThemeBuilderFixtures::templatePost(1065),
+            ThemeBuilderFixtures::layout(1061),
+            ThemeBuilderFixtures::layout(1062, $bodyFields),
+            ThemeBuilderFixtures::layout(1063),
+        ]);
+    }
+
+    private static function ability(DiviThemeBuilder $store, ?FakeChangeLog $log = null): TbAssignAbility
+    {
+        return new TbAssignAbility(
+            ThemeBuilderFixtures::access([], true, $store),
+            new TemplateConditions($store),
+            $log ?? DiviWriterFixture::log()
+        );
+    }
+
+    /** @return array<string, mixed> */
+    private static function input(Template $template, array $extra = []): array
+    {
+        return array_merge(
+            ['template_id' => $template->id, 'template_rev' => $template->rev(), 'use_on' => [self::PERSONS]],
+            $extra
+        );
+    }
+
+    public function testSetsConditionsOfADisabledTemplateAtOnce(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066);
+        $store = ThemeBuilderFixtures::store([ThemeBuilderFixtures::template(1065), $template]);
+        $store->shouldReceive('setConditions')->once()->with(1066, [self::PERSONS], []);
+        $store->shouldReceive('clearCaches')->never();
+
+        $result = self::ability($store)->execute(self::input($template));
+
+        self::assertTrue($result['ok']);
+        self::assertFalse($result['live']);
+        self::assertSame(['use_on' => ['singular:post_type:page:id:1053'], 'exclude_from' => []], $result['previous']);
+        self::assertStringContainsString('ohne Wirkung auf die Website', $result['summary']);
+    }
+
+    /** Ruling Q9/B22: live → dry run + confirm; ruling Q3/B3: the dry run shows both lists before and after. */
+    public function testActiveTemplateNeedsConfirm(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066, ['enabled' => true]);
+        $other = ThemeBuilderFixtures::template(1070, ['enabled' => true, 'title' => 'Personen alt', 'use_on' => [self::PERSONS]]);
+        $store = ThemeBuilderFixtures::store([$template, $other]);
+        $calls = 0;
+        $store->shouldReceive('setConditions')->andReturnUsing(static function () use (&$calls): void {
+            ++$calls;
+        });
+        $store->shouldReceive('clearCaches')->once();
+
+        $dry = self::ability($store)->execute(self::input($template));
+        self::assertToolError($dry, 'confirm_required');
+        self::assertSame(0, $calls);
+        self::assertSame(['use_on' => ['Bestimmte Seiten: 1053'], 'exclude_from' => []], $dry->get_error_data()['before']);
+        self::assertSame(['use_on' => ['Alle Personen'], 'exclude_from' => []], $dry->get_error_data()['after']);
+        self::assertSame(
+            [['id' => 1070, 'title' => 'Personen alt', 'conditions' => [self::PERSONS]]],
+            $dry->get_error_data()['overlaps']
+        );
+
+        $result = self::ability($store)->execute(self::input($template, ['confirm' => true]));
+        self::assertTrue($result['ok']);
+        self::assertTrue($result['live']);
+        self::assertStringContainsString('wirkt sofort', $result['summary']);
+        self::assertSame(1, $calls);
+    }
+
+    /** Ruling Q3/B3: an omitted exclude_from stays as it is; an explicit [] clears it – shown in the dry run. */
+    public function testOmittedExcludeFromStaysAndAnEmptyListClearsIt(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066, ['exclude_from' => ['singular:post_type:page:id:1054']]);
+        $store = ThemeBuilderFixtures::store([$template]);
+        $written = [];
+        $store->shouldReceive('setConditions')->andReturnUsing(
+            static function (int $id, array $useOn, array $excludeFrom) use (&$written): void {
+                $written[] = $excludeFrom;
+            }
+        );
+
+        self::ability($store)->execute(self::input($template));
+        self::ability($store)->execute(self::input($template, ['exclude_from' => []]));
+        self::ability($store)->execute(self::input($template, ['exclude_from' => ['homepage']]));
+
+        self::assertSame([['singular:post_type:page:id:1054'], [], ['homepage']], $written);
+
+        $live = ThemeBuilderFixtures::template(1066, ['enabled' => true, 'exclude_from' => ['singular:post_type:page:id:1054']]);
+        $dry = self::ability(ThemeBuilderFixtures::store([$live]))->execute(self::input($live, ['exclude_from' => []]));
+        self::assertToolError($dry, 'confirm_required');
+        self::assertSame(['Bestimmte Seiten: 1054'], $dry->get_error_data()['before']['exclude_from']);
+        self::assertSame([], $dry->get_error_data()['after']['exclude_from']);
+        self::assertStringContainsString('Ausnahmen', self::clientError($dry)['message']);
+    }
+
+    /** Ruling Q8/B9: other live templates of the same family are named as possible overlaps. */
+    public function testDryRunNamesPossibleOverlaps(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066, ['enabled' => true]);
+        $pages = ThemeBuilderFixtures::template(1070, [
+            'enabled' => true,
+            'title' => 'Alle Seiten',
+            'use_on' => ['singular:post_type:page:all'],
+        ]);
+        $store = ThemeBuilderFixtures::store([$template, $pages]);
+
+        $dry = self::ability($store)->execute(self::input($template, ['use_on' => ['homepage']]));
+
+        self::assertSame([], $dry->get_error_data()['overlaps']);
+        self::assertSame(
+            [['id' => 1070, 'title' => 'Alle Seiten', 'conditions' => ['singular:post_type:page:all']]],
+            $dry->get_error_data()['possible_overlaps']
+        );
+    }
+
+    public function testReattachKeepsTheTemplateDisabledAndUnmarksItsLayouts(): void
+    {
+        $detached = ThemeBuilderFixtures::template(1066, [
+            'enabled' => true,
+            'attached' => false,
+            'marked_unused' => '2026-09-20 08:00:00',
+        ]);
+        $store = ThemeBuilderFixtures::store([ThemeBuilderFixtures::template(1065)], 0, [$detached]);
+
+        $refused = self::ability($store)->execute(self::input($detached));
+        self::assertToolError($refused, 'validation_failed');
+        self::assertArrayHasKey('reattach', self::errorFields($refused));
+        self::assertStringContainsString('2026-09-20', self::clientError($refused)['message']);
+
+        $store->shouldReceive('setEnabled')->once()->with(1066, false);
+        $store->shouldReceive('attach')->once()->with(1064, 1066);
+        $unmarked = [];
+        $store->shouldReceive('unmarkUnused')->andReturnUsing(static function (int $id) use (&$unmarked): void {
+            $unmarked[] = $id;
+        });
+        $store->shouldReceive('setConditions')->once()->with(1066, [self::PERSONS], []);
+
+        $log = DiviWriterFixture::log();
+        $result = self::ability($store, $log)->execute(self::input($detached, ['reattach' => true]));
+
+        self::assertTrue($result['ok']);
+        self::assertSame([1066, 1061, 1062, 1063], $unmarked);
+        self::assertStringContainsString('wieder zugeordnet', $log->summaries()[0]);
+    }
+
+    /** Ruling Q8/B10: a layout Divi trashed meanwhile blocks the reattach; nothing is written. */
+    public function testReattachNeedsPublishedLayouts(): void
+    {
+        self::givenPosts(['post_status' => 'trash']);
+        $detached = ThemeBuilderFixtures::template(1066, ['attached' => false]);
+        $store = ThemeBuilderFixtures::store([], 0, [$detached]);
+        foreach (['setEnabled', 'attach', 'unmarkUnused', 'setConditions'] as $method) {
+            $store->shouldReceive($method)->never();
+        }
+
+        $refused = self::ability($store, FakeChangeLog::forbidden())->execute(self::input($detached, ['reattach' => true]));
+
+        self::assertToolError($refused, 'validation_failed');
+        self::assertSame(['layouts.body'], array_keys(self::errorFields($refused)));
+    }
+
+    public function testFailedReattachDetachesAndRestoresTheFlag(): void
+    {
+        $detached = ThemeBuilderFixtures::template(1066, ['enabled' => true, 'attached' => false]);
+        $store = ThemeBuilderFixtures::store([], 0, [$detached]);
+        $steps = [];
+        $store->shouldReceive('setEnabled')->andReturnUsing(static function (int $id, bool $on) use (&$steps): void {
+            $steps[] = 'enabled:' . ($on ? '1' : '0');
+        });
+        $store->shouldReceive('attach')->andReturnUsing(static function () use (&$steps): void {
+            $steps[] = 'attach';
+        });
+        $store->shouldReceive('unmarkUnused');
+        $store->shouldReceive('setConditions')->andReturnUsing(static function (int $id, array $useOn) use (&$steps): void {
+            $steps[] = 'conditions:' . implode(',', $useOn);
+            if ($useOn === [self::PERSONS]) {
+                throw new RuntimeException('add_post_meta failed');
+            }
+        });
+        $store->shouldReceive('detach')->once()->with(1064, 1066)->andReturnUsing(static function () use (&$steps): void {
+            $steps[] = 'detach';
+        });
+
+        try {
+            self::ability($store, FakeChangeLog::forbidden())->execute(self::input($detached, ['reattach' => true]));
+            self::fail('no WriteFailed');
+        } catch (WriteFailed $e) {
+            self::assertTrue($e->rolledBack);
+        }
+        self::assertSame(
+            ['enabled:0', 'attach', 'conditions:' . self::PERSONS, 'conditions:singular:post_type:page:id:1053', 'detach', 'enabled:1'],
+            $steps
+        );
+    }
+
+    public function testFailureRestoresThePreviousConditions(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066);
+        $store = ThemeBuilderFixtures::store([$template]);
+        $calls = [];
+        $store->shouldReceive('setConditions')->andReturnUsing(static function (int $id, array $useOn) use (&$calls): void {
+            $calls[] = $useOn;
+            if (count($calls) === 1) {
+                throw new RuntimeException('add_post_meta failed');
+            }
+        });
+
+        try {
+            self::ability($store, FakeChangeLog::forbidden())->execute(self::input($template));
+            self::fail('no WriteFailed');
+        } catch (WriteFailed $e) {
+            self::assertTrue($e->rolledBack);
+        }
+        self::assertSame([[self::PERSONS], ['singular:post_type:page:id:1053']], $calls);
+    }
+
+    public function testFailedRestoreIsAPartialWrite(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066);
+        $store = ThemeBuilderFixtures::store([$template]);
+        $store->shouldReceive('setConditions')->andThrow(new RuntimeException('database gone'));
+        $log = FakeChangeLog::partialsOnly();
+
+        try {
+            self::ability($store, $log)->execute(self::input($template));
+            self::fail('no WriteFailed');
+        } catch (WriteFailed $e) {
+            self::assertFalse($e->rolledBack);
+        }
+        $log->assertPartials(['ability' => 'lit/tb-assign', 'object_type' => 'et_template', 'object_id' => '1066']);
+    }
+
+    public function testChangeLogKeepsThePreviousConditions(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066, ['exclude_from' => ['homepage']]);
+        $store = ThemeBuilderFixtures::store([$template]);
+        $store->shouldReceive('setConditions');
+        $log = DiviWriterFixture::log();
+
+        $result = self::ability($store, $log)->execute(self::input($template));
+
+        self::assertStringContainsString('singular:post_type:page:id:1053', $log->summaries()[0]);
+        self::assertStringContainsString('homepage', $log->summaries()[0]);
+        self::assertSame(['use_on' => ['singular:post_type:page:id:1053'], 'exclude_from' => ['homepage']], $result['previous']);
+    }
+
+    public function testInvalidConditionsAndMissingUseOnWriteNothing(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066);
+        $store = ThemeBuilderFixtures::store([$template]);
+        $store->shouldReceive('setConditions')->never();
+
+        self::assertToolError(self::ability($store)->execute(self::input($template, ['use_on' => ['erfunden']])), 'validation_failed');
+        self::assertToolError(
+            self::ability($store)->execute(self::input($template, ['exclude_from' => ['erfunden']])),
+            'validation_failed'
+        );
+        $noList = self::input($template);
+        unset($noList['use_on']);
+        self::assertToolError(self::ability($store)->execute($noList), 'validation_failed');
+        self::assertTrue(self::ability($store)->annotations()['destructive']);
+        self::assertFalse(self::ability($store)->isDirect());
+    }
+
+    public function testPermissionUsesTheSameGate(): void
+    {
+        $template = ThemeBuilderFixtures::template(1066);
+        $store = ThemeBuilderFixtures::store([$template]);
+
+        self::assertTrue(self::ability($store)->permission(self::input($template)));
+        self::assertToolError(self::ability($store)->permission(self::input($template, ['template_rev' => 'x'])), 'rev_mismatch');
+        self::assertToolError(self::ability($store)->permission(self::input($template, ['template_id' => 4711])), 'not_found');
+    }
+}
diff --git a/tests/Unit/Integrations/Divi/ThemeBuilder/TemplateTest.php b/tests/Unit/Integrations/Divi/ThemeBuilder/TemplateTest.php
index 696df45..9a648ae 100644
--- a/tests/Unit/Integrations/Divi/ThemeBuilder/TemplateTest.php
+++ b/tests/Unit/Integrations/Divi/ThemeBuilder/TemplateTest.php
@@ -92,4 +92,41 @@ final class TemplateTest extends TestCase
         );
         self::assertSame([], Template::overlaps([$other], 1070, ['homepage']));
     }
+
+    /** Ruling Q8/B9: conditions of the same family may overlap (Divi then picks one template). */
+    public function testPossibleOverlapsNameOtherLiveTemplatesOfTheSameFamily(): void
+    {
+        $pages = ThemeBuilderFixtures::template(1070, [
+            'enabled' => true,
+            'title' => 'Seiten',
+            'use_on' => ['singular:post_type:page:all', 'search'],
+        ]);
+        $archives = ThemeBuilderFixtures::template(1071, ['enabled' => true, 'title' => 'Archive', 'use_on' => ['archive:all']]);
+        $inTerm = ThemeBuilderFixtures::template(1072, [
+            'enabled' => true,
+            'title' => 'Beiträge einer Kategorie',
+            'use_on' => ['singular:taxonomy:category:term:id:5'],
+        ]);
+        $disabled = ThemeBuilderFixtures::template(1073, ['use_on' => ['singular:post_type:page:all']]);
+        $live = [$pages, $archives, $inTerm, $disabled];
+
+        self::assertSame(
+            [
+                ['id' => 1070, 'title' => 'Seiten', 'conditions' => ['singular:post_type:page:all']],
+                ['id' => 1072, 'title' => 'Beiträge einer Kategorie', 'conditions' => ['singular:taxonomy:category:term:id:5']],
+            ],
+            Template::possibleOverlaps($live, 1066, ['singular:post_type:page:id:1053'])
+        );
+        self::assertSame(
+            [['id' => 1071, 'title' => 'Archive', 'conditions' => ['archive:all']]],
+            Template::possibleOverlaps($live, 1066, ['archive:taxonomy:category:term:id:5'])
+        );
+        self::assertSame([], Template::possibleOverlaps($live, 1066, ['search']), 'identical ones are overlaps()');
+        self::assertSame([], Template::possibleOverlaps($live, 1066, ['404']));
+        self::assertSame(
+            ['id' => 1070, 'title' => 'Seiten', 'conditions' => ['singular:post_type:page:all']],
+            Template::possibleOverlaps($live, 1066, ['homepage'])[0],
+            'a static front page is a page'
+        );
+    }
 }
diff --git a/tests/Unit/Integrations/Divi/ThemeBuilder/ThemeBuilderAccessTest.php b/tests/Unit/Integrations/Divi/ThemeBuilder/ThemeBuilderAccessTest.php
index b659e19..2218f2a 100644
--- a/tests/Unit/Integrations/Divi/ThemeBuilder/ThemeBuilderAccessTest.php
+++ b/tests/Unit/Integrations/Divi/ThemeBuilder/ThemeBuilderAccessTest.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace LIT\MCP\Tests\Unit\Integrations\Divi\ThemeBuilder;
 
 use Brain\Monkey\Functions;
+use LIT\MCP\Integrations\Divi\ThemeBuilder\Template;
 use LIT\MCP\Integrations\WordPress\PostGuard;
 use LIT\MCP\Tests\Support\LibraryFixtures;
 use LIT\MCP\Tests\Support\ThemeBuilderFixtures;
@@ -166,4 +167,39 @@ final class ThemeBuilderAccessTest extends TestCase
         $refusal = ThemeBuilderFixtures::access()->layoutsRefusal(ThemeBuilderFixtures::template());
         self::assertSame(['layouts.body'], array_keys(self::errorFields($refusal)), 'a footer is no body');
     }
+
+    public function testChangeableTemplateNeedsRightsNoDraftNoDefaultAndTheCurrentRev(): void
+    {
+        LibraryFixtures::given([ThemeBuilderFixtures::templatePost(1066), ThemeBuilderFixtures::templatePost(1065)]);
+        $store = ThemeBuilderFixtures::store([ThemeBuilderFixtures::template(1065), ThemeBuilderFixtures::template(1066)]);
+        $access = ThemeBuilderFixtures::access([], true, $store);
+        $rev = ThemeBuilderFixtures::template(1066)->rev();
+
+        self::assertInstanceOf(Template::class, $access->changeableTemplate(['template_id' => 1066, 'template_rev' => $rev]));
+        self::assertToolError($access->changeableTemplate(['template_id' => 1066, 'template_rev' => 'alt']), 'rev_mismatch');
+        self::assertToolError(
+            $access->changeableTemplate(['template_id' => 1065, 'template_rev' => ThemeBuilderFixtures::template(1065)->rev()]),
+            'unsupported'
+        );
+        $draft = ThemeBuilderFixtures::access([], true, ThemeBuilderFixtures::store([ThemeBuilderFixtures::template(1066)], 999));
+        self::assertToolError($draft->changeableTemplate(['template_id' => 1066, 'template_rev' => $rev]), 'unsupported');
+        self::assertToolError(
+            ThemeBuilderFixtures::access([], false, $store)->changeableTemplate(['template_id' => 1066, 'template_rev' => $rev]),
+            'forbidden'
+        );
+    }
+
+    /** Ruling Q18: a template the user may not edit answers like a missing one, also for writing. */
+    public function testChangeableTemplateHidesTemplatesTheUserMayNotEdit(): void
+    {
+        $store = ThemeBuilderFixtures::store([ThemeBuilderFixtures::template(1066)]);
+        $rev = ThemeBuilderFixtures::template(1066)->rev();
+        LibraryFixtures::given([ThemeBuilderFixtures::templatePost(1066)], ['edit_post']);
+        $hidden = ThemeBuilderFixtures::access([], true, $store)->changeableTemplate(['template_id' => 1066, 'template_rev' => $rev]);
+        LibraryFixtures::given([]);
+        $missing = ThemeBuilderFixtures::access([], true, $store)->changeableTemplate(['template_id' => 1066, 'template_rev' => $rev]);
+
+        self::assertToolError($hidden, 'not_found');
+        self::assertSame(self::clientError($missing), self::clientError($hidden));
+    }
 }