Don't show the inline toggle selector on Special:MobileDiff

Have Article opt in to inline toggle switch display, so that random
callers of DifferenceEngine::showDiffPage() do not receive a
non-functional format selector.

Bug: T342158
Change-Id: Id4e38c2a20b5381e5f70b1244304da2895eaf8e7

5 files changed, 29 insertions, 3 deletions

diff --git a/includes/content/ContentHandler.php b/includes/content/ContentHandler.php
index 3d4b60fce347..1de61d4d37e2 100644
--- a/includes/content/ContentHandler.php
+++ b/includes/content/ContentHandler.php
@@ -723,6 +723,9 @@ abstract class ContentHandler {
 		}
 		$slotDiffRenderer->setFormat( $format );
 		$slotDiffRenderer->setTextDiffer( $textDiffer );
+		if ( $options['inline-toggle'] ?? false ) {
+			$slotDiffRenderer->setInlineToggleEnabled();
+		}
 
 		return $slotDiffRenderer;
 	}
diff --git a/includes/diff/DifferenceEngine.php b/includes/diff/DifferenceEngine.php
index 102efcd9bc5f..317ccaa38620 100644
--- a/includes/diff/DifferenceEngine.php
+++ b/includes/diff/DifferenceEngine.php
@@ -1499,6 +1499,9 @@ class DifferenceEngine extends ContextSource {
 	 *      the site default format (table) will be used.
 	 *    - expand-url: If true, put full URLs in href attributes (for action=render)
 	 *      FIXME: expand-url is not a slot diff option, it is a DifferenceEngine option.
+	 *    - inline-toggle: If true, and the inline format is supported and
+	 *      $wgShowDiffToggleSwitch is true, a format selector toggle switch
+	 *      will be shown.
 	 */
 	public function setSlotDiffOptions( $options ) {
 		$validatedOptions = [];
@@ -1510,6 +1513,9 @@ class DifferenceEngine extends ContextSource {
 		if ( !empty( $options['expand-url'] ) ) {
 			$validatedOptions['expand-url'] = true;
 		}
+		if ( !empty( $options['inline-toggle'] ) ) {
+			$validatedOptions['inline-toggle'] = true;
+		}
 		$this->slotDiffOptions = $validatedOptions;
 	}
 
diff --git a/includes/diff/TextSlotDiffRenderer.php b/includes/diff/TextSlotDiffRenderer.php
index 8387e45933a3..f839ff4c122d 100644
--- a/includes/diff/TextSlotDiffRenderer.php
+++ b/includes/diff/TextSlotDiffRenderer.php
@@ -75,6 +75,9 @@ class TextSlotDiffRenderer extends SlotDiffRenderer {
 	/** @var TextDiffer|null */
 	private $textDiffer;
 
+	/** @var bool */
+	private $inlineToggleEnabled = false;
+
 	/** @inheritDoc */
 	public function getExtraCacheKeys() {
 		return $this->textDiffer->getCacheKeys( [ $this->format ] );
@@ -201,6 +204,16 @@ class TextSlotDiffRenderer extends SlotDiffRenderer {
 	}
 
 	/**
+	 * Set a flag indicating whether the inline toggle switch is shown.
+	 *
+	 * @since 1.41
+	 * @param bool $enabled
+	 */
+	public function setInlineToggleEnabled( $enabled = true ) {
+		$this->inlineToggleEnabled = $enabled;
+	}
+
+	/**
 	 * Get the content model ID that this renderer acts on
 	 *
 	 * @since 1.41
@@ -230,9 +243,11 @@ class TextSlotDiffRenderer extends SlotDiffRenderer {
 	public function getTablePrefix( IContextSource $context, Title $newTitle ): array {
 		$parts = $this->getTextDiffer()->getTablePrefixes( $this->format );
 
-		$showDiffToggleSwitch = $context->getConfig()->get( MainConfigNames::ShowDiffToggleSwitch );
+		$showDiffToggleSwitch = $this->inlineToggleEnabled
+			&& $context->getConfig()->get( MainConfigNames::ShowDiffToggleSwitch )
+			&& $this->getTextDiffer()->hasFormat( 'inline' );
 		// If we support the inline type, add a toggle switch
-		if ( $showDiffToggleSwitch && $this->getTextDiffer()->hasFormat( 'inline' ) ) {
+		if ( $showDiffToggleSwitch ) {
 			$values = $context->getRequest()->getValues();
 			$isInlineDiffType = $this->format === 'inline';
 			unset( $values[ 'diff-type' ] );
diff --git a/includes/page/Article.php b/includes/page/Article.php
index ec61e3933138..7ca0de3eab83 100644
--- a/includes/page/Article.php
+++ b/includes/page/Article.php
@@ -964,7 +964,8 @@ class Article implements Page {
 
 		$de->setSlotDiffOptions( [
 			'diff-type' => $diffType,
-			'expand-url' => $this->viewIsRenderAction
+			'expand-url' => $this->viewIsRenderAction,
+			'inline-toggle' => true,
 		] );
 		$de->showDiffPage( $this->isDiffOnlyView() );
 
diff --git a/tests/phpunit/includes/diff/TextSlotDiffRendererTest.php b/tests/phpunit/includes/diff/TextSlotDiffRendererTest.php
index 357ea76d6b89..25726dc9b216 100644
--- a/tests/phpunit/includes/diff/TextSlotDiffRendererTest.php
+++ b/tests/phpunit/includes/diff/TextSlotDiffRendererTest.php
@@ -200,6 +200,7 @@ class TextSlotDiffRendererTest extends MediaWikiIntegrationTestCase {
 		$slotDiffRenderer = $this->getTextSlotDiffRenderer( 'qqx' );
 		$slotDiffRenderer->setHookContainer( $this->createHookContainer() );
 		$slotDiffRenderer->setEngine( $engine );
+		$slotDiffRenderer->setInlineToggleEnabled();
 
 		$context = new RequestContext;
 		$context->setLanguage( 'qqx' );