Bind the context parse to the revision and clarify provider docs

The parse that fills categories and parserProperties ran without a
revision id, i.e. as a preview-like parse: revision-context magic words
({{REVISIONID}}, {{REVISIONUSER}}, ...) and parser hooks that read the
revision while recording page properties resolved against nothing, so
the recorded values could diverge from what core stored for the same
revision. That mattered little while the parse only fed categories, but
the parse products are now published to providers as the recommended
derivation path. The fix passes the revision id through
ContentParseParams. The new test pins the behavior with a
{{DEFAULTSORT:Rev{{REVISIONID}}}} page: it records Rev without the fix
and Rev<id> with it, and a second stored revision ensures resolving the
page's latest revision instead of the provided one also fails.

The content-unavailable sentinels (content and contentModel empty,
parserProperties and categories empty when the main-slot content is
hidden) had no covering test, so type-clean drift such as switching the
builder to getContentOrThrow would pass the whole suite while making
undeletion of a page with rev-deleted history fatal in production; the
new test suppresses a real revision and asserts what a provider
receives. The contentModel test only exercised wikitext, the one value
a hardcode would also produce, so a JSON page now pins that the model
comes from the actual content.

In extending.md, the sentence introducing the context now names the
content and parse products, and the section states when providers
actually run: when a revision is stored for a page carrying Subject
data (including undeletions) and during RebuildGraphDatabases runs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: malberts

docs/reference/extending.md

@@ -74,7 +74,10 @@ $registrar->addNeo4jValueBuilder( ColorType::NAME, static fn ( $value ) => $valu
 ### Page Property Providers
 
 Page Property Providers contribute key/value metadata to the Page node in the graph (queryable via Cypher;
-Neo4j is currently the only graph backend). Implement `PagePropertyProvider`:
+Neo4j is currently the only graph backend). They run when a revision is stored for a page carrying Subject
+data (including undeletions), and again for such pages when the graph is rebuilt with the
+`RebuildGraphDatabases` maintenance script. Pages without Subject data are not stored in the graph, so
+providers are never invoked for them. Implement `PagePropertyProvider`:
 
 ```php
 class StaticPagePropertyProvider implements PagePropertyProvider {
@@ -87,14 +90,14 @@ class StaticPagePropertyProvider implements PagePropertyProvider {
 ```
 
 Register with `NeoWikiRegistrar::addPagePropertyProvider()`. The context exposes the page id, title,
-creation and modification times, categories, and last editor, so providers can derive Page Properties
-from the page content without re-fetching or re-parsing it.
+creation and modification times, categories, and last editor, as well as the page content and its parse
+products, so providers can derive Page Properties from the page content without re-fetching or re-parsing it.
 
-To derive Page Properties from the content, prefer the parse products: `categories`, and
+To derive Page Properties from the content, prefer the parse products: `categories` and
 `parserProperties` — the MediaWiki page properties recorded during parsing (e.g. those a parser hook
 sets via `ParserOutput::setPageProperty`). These are template-expansion-safe and robust. (Note that
 `parserProperties` are an input from MediaWiki's parse; they are not the NeoWiki Page Properties this
-provider returns.) The raw main slot `content` and its `contentModel` are also exposed, but scraping
+provider returns.) The raw main slot `content` and its `contentModel` are the fallback: scraping
 raw wikitext is fragile — reach for them mainly when handling a custom, non-wikitext content model that
 the parse products do not cover. Example:
 [`src/StaticPagePropertyProvider.php`](https://github.com/ProfessionalWiki/NeoWiki/blob/master/tests/RedHerb/src/StaticPagePropertyProvider.php).

src/PagePropertiesBuilder.php

@@ -61,7 +61,7 @@ private function buildContext( RevisionRecord $revision, ?UserIdentity $user ):
 
 	private function parse( Content $content, RevisionRecord $revision ): ParserOutput {
 		return $this->contentHandlerFactory->getContentHandler( $content->getModel() )
-			->getParserOutput( $content, new ContentParseParams( $revision->getPage() ) );
+			->getParserOutput( $content, new ContentParseParams( $revision->getPage(), $revision->getId() ) );
 	}
 
 	private function getCreationTime( RevisionRecord $revision ): string {

tests/phpunit/PagePropertiesBuilderTest.php

@@ -4,6 +4,7 @@
 
 namespace ProfessionalWiki\NeoWiki\Tests;
 
+use MediaWiki\Revision\RevisionRecord;
 use ProfessionalWiki\NeoWiki\Domain\Page\PagePropertyProviderContext;
 use ProfessionalWiki\NeoWiki\Domain\Page\PagePropertyProviderRegistry;
 use ProfessionalWiki\NeoWiki\PagePropertiesBuilder;
@@ -39,9 +40,46 @@ public function testProviderReceivesCategoriesFromParsedContent(): void {
 		$this->assertSame( [ 'Cats' ], $context->categories );
 	}
 
+	public function testParseIsBoundToTheProvidedRevision(): void {
+		$revision = $this->editPage( 'PagePropertiesBuilderTestPage', '{{DEFAULTSORT:Rev{{REVISIONID}}}}' )->getNewRevision();
+		$this->editPage( 'PagePropertiesBuilderTestPage', 'Newer revision without a defaultsort' );
+
+		$this->assertSame(
+			'Rev' . $revision->getId(),
+			$this->getContextForRevision( $revision )->parserProperties['defaultsort']
+		);
+	}
+
+	public function testProviderReceivesContentModelOfNonWikitextContent(): void {
+		$revision = $this->editPage( 'MediaWiki:PagePropertiesBuilderTest.json', '{ "answer": 42 }' )->getNewRevision();
+
+		$this->assertSame( CONTENT_MODEL_JSON, $this->getContextForRevision( $revision )->contentModel );
+	}
+
+	public function testContextHasEmptySentinelsWhenContentIsUnavailable(): void {
+		$revision = $this->editPage( 'PagePropertiesBuilderTestPage', 'Hidden [[Category:Cats]] {{DEFAULTSORT:Zebra}}' )->getNewRevision();
+		$this->editPage( 'PagePropertiesBuilderTestPage', 'Newer public revision' );
+		$this->revisionDelete( $revision );
+
+		$context = $this->getContextForRevision( $this->getSuppressedRevision( $revision->getId() ) );
+
+		$this->assertSame( '', $context->content );
+		$this->assertSame( '', $context->contentModel );
+		$this->assertSame( [], $context->parserProperties );
+		$this->assertSame( [], $context->categories );
+	}
+
+	private function getSuppressedRevision( int $revisionId ): RevisionRecord {
+		return $this->getServiceContainer()->getRevisionStore()->getRevisionById( $revisionId );
+	}
+
 	private function getContextForNewPageWithContent( string $wikitext ): PagePropertyProviderContext {
-		$revision = $this->editPage( 'PagePropertiesBuilderTestPage', $wikitext )->getNewRevision();
+		return $this->getContextForRevision(
+			$this->editPage( 'PagePropertiesBuilderTestPage', $wikitext )->getNewRevision()
+		);
+	}
 
+	private function getContextForRevision( RevisionRecord $revision ): PagePropertyProviderContext {
 		$spy = new SpyPagePropertyProvider();
 
 		$this->newPagePropertiesBuilder( $spy )->getPagePropertiesFor( $revision, null );