Automattic · tbradsha · Nov 20, 2025 · Nov 12, 2025 · Nov 12, 2025 · Nov 12, 2025
diff --git a/projects/packages/analyzer/.phan/baseline.php b/projects/packages/analyzer/.phan/baseline.php
@@ -11,16 +11,13 @@
     // # Issue statistics:
     // PhanUndeclaredProperty : 25+ occurrences
     // PhanTypeMismatchArgument : 8 occurrences
-    // PhanPossiblyUndeclaredVariable : 7 occurrences
     // PhanParamSignatureMismatch : 6 occurrences
     // PhanPluginDuplicateConditionalNullCoalescing : 6 occurrences
     // PhanTypeMismatchReturnProbablyReal : 6 occurrences
     // PhanUndeclaredClassMethod : 6 occurrences
     // PhanUndeclaredMethod : 6 occurrences
     // PhanTypeArraySuspiciousNullable : 5 occurrences
-    // PhanTypeMismatchArgumentNullable : 5 occurrences
     // PhanUndeclaredTypeParameter : 4 occurrences
-    // PhanNonClassMethodCall : 2 occurrences
     // PhanPluginDuplicateCatchStatementBody : 2 occurrences
     // PhanTypeMismatchDeclaredParam : 2 occurrences
     // PhanUndeclaredClassStaticProperty : 2 occurrences
@@ -49,7 +46,6 @@
         'src/api/class-model.php' => ['PhanTypeArraySuspiciousNullable'],
         'src/api/class-plugin-downloader.php' => ['PhanPluginDuplicateExpressionAssignmentOperation'],
         'src/class-declarations.php' => ['PhanPluginDuplicateCatchStatementBody'],
-        'src/class-differences.php' => ['PhanNonClassMethodCall', 'PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgumentNullable'],
         'src/class-invocations.php' => ['PhanPluginDuplicateCatchStatementBody'],
         'src/class-utils.php' => ['PhanTypeMismatchArgument', 'PhanUndeclaredMethod', 'PhanUndeclaredProperty', 'PhanUndeclaredTypeParameter'],
         'src/class-warnings.php' => ['PhanUndeclaredMethod'],

diff --git a/projects/packages/analyzer/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/analyzer/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/analyzer/src/class-differences.php b/projects/packages/analyzer/src/class-differences.php
@@ -36,6 +36,7 @@ public function find( $new_declarations, $prev_declarations, $new_root = null, $
 			$moved                 = false;
 			$moved_with_empty_file = false;
 			$deprecated            = false;
+			$new_declaration       = false;
 			foreach ( $new_declarations->get() as $new_declaration ) {
 
 				if ( $prev_declaration->match( $new_declaration ) ) {
@@ -56,7 +57,7 @@ public function find( $new_declarations, $prev_declarations, $new_root = null, $
 							$moved = true;
 						}
 					}
-					$matched = true;
+					$matched = $new_declaration;
 					break;
 				} elseif ( $prev_declaration->partial_match( $new_declaration ) ) {
 					// TODO this is to catch things like function args changed, method the same
@@ -69,7 +70,7 @@ public function find( $new_declarations, $prev_declarations, $new_root = null, $
 			}
 
 			// Add differences for any detected deprecations.
-			if ( $deprecated ) {
+			if ( $deprecated && $matched ) {
 				switch ( $new_declaration->type() ) {
 					case 'method':
 						$this->add( new Differences\Class_Method_Deprecated( $prev_declaration ) );

diff --git a/projects/packages/backup/.phan/baseline.php b/projects/packages/backup/.phan/baseline.php
@@ -12,11 +12,10 @@
     // PhanTypeMismatchReturnProbablyReal : 15+ occurrences
     // PhanTypeMismatchReturn : 6 occurrences
     // PhanUndeclaredStaticMethod : 2 occurrences
-    // PhanPossiblyUndeclaredVariable : 1 occurrence
 
     // Currently, file_suppressions and directory_suppressions are the only supported suppressions
     'file_suppressions' => [
-        'src/class-jetpack-backup.php' => ['PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal', 'PhanUndeclaredStaticMethod'],
+        'src/class-jetpack-backup.php' => ['PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal', 'PhanUndeclaredStaticMethod'],
         'src/class-rest-controller.php' => ['PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal'],
     ],
     // 'directory_suppressions' => ['src/directory_name' => ['PhanIssueName1', 'PhanIssueName2']] can be manually added if needed.

diff --git a/projects/packages/backup/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/backup/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/backup/src/class-jetpack-backup.php b/projects/packages/backup/src/class-jetpack-backup.php
@@ -717,17 +717,14 @@ public static function get_storage_addon_upsell_slug( $bytes_used, $bytes_availa
 				return $upsell_products[ $bytes_1tb ];
 			}
 
+			$matched_bytes = $bytes_10gb;
 			foreach ( $upsell_products as $bytes => $product ) {
 				if ( $bytes > $additional_bytes_needed ) {
 					$matched_bytes = $bytes;
 					break;
 				}
 			}
 
-			if ( ! $matched_bytes ) {
-				$matched_bytes = $bytes_10gb;
-			}
-
 			return $upsell_products[ $matched_bytes ];
 		}
 

diff --git a/projects/packages/connection/.phan/baseline.php b/projects/packages/connection/.phan/baseline.php
@@ -21,14 +21,13 @@
     // PhanDeprecatedFunction : 2 occurrences
     // PhanNonClassMethodCall : 2 occurrences
     // PhanPluginUnreachableCode : 2 occurrences
-    // PhanPossiblyUndeclaredVariable : 2 occurrences
     // PhanTypeMismatchPropertyDefault : 2 occurrences
-    // PhanTypeMismatchReturnNullable : 2 occurrences
     // PhanTypePossiblyInvalidDimOffset : 2 occurrences
     // PhanPluginDuplicateAdjacentStatement : 1 occurrence
     // PhanPluginSimplifyExpressionBool : 1 occurrence
     // PhanTypeMismatchArgumentNullable : 1 occurrence
     // PhanTypeMismatchDeclaredParamNullable : 1 occurrence
+    // PhanTypeMismatchReturnNullable : 1 occurrence
     // PhanUndeclaredClassMethod : 1 occurrence
 
     // Currently, file_suppressions and directory_suppressions are the only supported suppressions
@@ -40,7 +39,6 @@
         'src/class-error-handler.php' => ['PhanTypeMismatchReturnProbablyReal'],
         'src/class-heartbeat.php' => ['PhanTypeMismatchPropertyDefault'],
         'src/class-manager.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchArgument', 'PhanTypeMismatchDeclaredParamNullable', 'PhanTypeMismatchDefault', 'PhanTypeMismatchPropertyProbablyReal', 'PhanTypeMismatchReturn', 'PhanTypeMismatchReturnNullable', 'PhanTypeMismatchReturnProbablyReal'],
-        'src/class-nonce-handler.php' => ['PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchReturnNullable'],
         'src/class-partner-coupon.php' => ['PhanPluginDuplicateConditionalNullCoalescing'],
         'src/class-partner.php' => ['PhanTypeMismatchPropertyProbablyReal'],
         'src/class-rest-authentication.php' => ['PhanTypeMismatchPropertyDefault', 'PhanTypeMismatchPropertyProbablyReal'],

diff --git a/projects/packages/connection/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/connection/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/connection/src/class-nonce-handler.php b/projects/packages/connection/src/class-nonce-handler.php
@@ -90,6 +90,8 @@ public function add( $timestamp, $nonce ) {
 		// Raw query so we can avoid races: add_option will also update.
 		$show_errors = $this->db->hide_errors();
 
+		$return = false;
+
 		// Running `try...finally` to make sure that we re-enable errors in case of an exception.
 		try {
 			$old_nonce = $this->db->get_row(
@@ -105,8 +107,6 @@ public function add( $timestamp, $nonce ) {
 						'no'
 					)
 				);
-			} else {
-				$return = false;
 			}
 		} finally {
 			$this->db->show_errors( $show_errors );

diff --git a/projects/packages/image-cdn/.phan/baseline.php b/projects/packages/image-cdn/.phan/baseline.php
@@ -13,11 +13,9 @@
     // PhanPluginSimplifyExpressionBool : 6 occurrences
     // PhanPluginDuplicateConditionalNullCoalescing : 4 occurrences
     // PhanTypeMismatchArgumentProbablyReal : 4 occurrences
-    // PhanPossiblyUndeclaredVariable : 2 occurrences
     // PhanTypeMismatchPropertyProbablyReal : 2 occurrences
     // PhanNonClassMethodCall : 1 occurrence
     // PhanTypeArraySuspicious : 1 occurrence
-    // PhanTypeMismatchArgumentNullable : 1 occurrence
     // PhanTypeMismatchArgumentNullableInternal : 1 occurrence
     // PhanTypeMismatchReturn : 1 occurrence
     // PhanTypeMismatchReturnProbablyReal : 1 occurrence
@@ -28,10 +26,10 @@
     // Currently, file_suppressions and directory_suppressions are the only supported suppressions
     'file_suppressions' => [
         'src/class-image-cdn-image-sizes.php' => ['PhanPluginSimplifyExpressionBool'],
-        'src/class-image-cdn.php' => ['PhanNonClassMethodCall', 'PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool', 'PhanPossiblyUndeclaredVariable', 'PhanTypeArraySuspicious', 'PhanTypeMismatchPropertyProbablyReal', 'PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal', 'PhanTypePossiblyInvalidDimOffset'],
+        'src/class-image-cdn.php' => ['PhanNonClassMethodCall', 'PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool', 'PhanTypeArraySuspicious', 'PhanTypeMismatchPropertyProbablyReal', 'PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal', 'PhanTypePossiblyInvalidDimOffset'],
         'src/compatibility/photon.php' => ['PhanTypeMismatchArgumentNullableInternal'],
         'tests/php/Image_CDN_Core_Test.php' => ['PhanTypeMismatchArgumentProbablyReal', 'PhanTypeObjectUnsetDeclaredProperty'],
-        'tests/php/Image_CDN_Test.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgumentNullable', 'PhanTypeMismatchPropertyProbablyReal', 'PhanUndeclaredMethod', 'PhanUndeclaredStaticMethod'],
+        'tests/php/Image_CDN_Test.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchPropertyProbablyReal', 'PhanUndeclaredMethod', 'PhanUndeclaredStaticMethod'],
     ],
     // 'directory_suppressions' => ['src/directory_name' => ['PhanIssueName1', 'PhanIssueName2']] can be manually added if needed.
     // (directory_suppressions will currently be ignored by subsequent calls to --save-baseline, but may be preserved in future Phan releases)

diff --git a/projects/packages/image-cdn/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/image-cdn/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/image-cdn/src/class-image-cdn.php b/projects/packages/image-cdn/src/class-image-cdn.php
@@ -363,8 +363,10 @@ public static function filter_the_content( $content ) {
 			}
 
 			// Identify image source.
-			$src_orig = $processor->get_attribute( 'src' );
-			$src      = $src_orig;
+			$src_orig             = $processor->get_attribute( 'src' );
+			$src                  = $src_orig;
+			$placeholder_src      = null;
+			$placeholder_src_orig = null;
 
 			/*
 			 * Only examine tags that are considered an image,
@@ -648,14 +650,12 @@ public static function filter_the_content( $content ) {
 					$processor->set_attribute( 'src', $photon_url );
 
 					// If Lazy Load is in use, pass placeholder image through Photon.
-					if ( isset( $placeholder_src ) && self::validate_image_url( $placeholder_src ) ) {
+					if ( $placeholder_src !== null && self::validate_image_url( $placeholder_src ) ) {
 						$placeholder_src = Image_CDN_Core::cdn_url( $placeholder_src );
 
 						if ( $placeholder_src !== $placeholder_src_orig ) {
 							$processor->set_attribute( $source_type, $placeholder_src );
 						}
-
-						unset( $placeholder_src );
 					}
 
 					// If we are not transforming the image with resize, fit, or letterbox (lb), then we should remove

diff --git a/projects/packages/image-cdn/tests/php/Image_CDN_Test.php b/projects/packages/image-cdn/tests/php/Image_CDN_Test.php
@@ -143,10 +143,10 @@ protected function helper_get_query( $data ) {
 	 * @return int Post ID (attachment) of the image.
 	 */
 	protected function helper_get_image( $size = 'large', $meta = true ) {
-		if ( 'large' === $size ) { // 1600x1200
-			$filename = __DIR__ . '/sample-content/test-image-large.png';
-		} elseif ( 'medium' === $size ) { // 1024x768
+		if ( 'medium' === $size ) { // 1024x768
 			$filename = __DIR__ . '/sample-content/test-image-medium.png';
+		} else { // 1600x1200 - default to 'large'
+			$filename = __DIR__ . '/sample-content/test-image-large.png';
 		}
 		// Add sizes that exist before uploading the file.
 		add_image_size( 'jetpack_soft_defined', 700, 500, false ); // Intentionally not a 1.33333 ratio.

diff --git a/projects/packages/publicize/.phan/baseline.php b/projects/packages/publicize/.phan/baseline.php
@@ -14,7 +14,6 @@
     // PhanPluginUnreachableCode : 4 occurrences
     // PhanTypeMismatchArgument : 3 occurrences
     // PhanUndeclaredClassMethod : 3 occurrences
-    // PhanPossiblyUndeclaredVariable : 2 occurrences
     // PhanTypeMismatchArgumentNullable : 2 occurrences
     // PhanTypeMismatchReturnProbablyReal : 2 occurrences
     // PhanTypeMissingReturn : 2 occurrences
@@ -35,7 +34,7 @@
         'src/class-keyring-helper.php' => ['PhanTypeMismatchArgumentProbablyReal', 'PhanTypeMismatchDefault'],
         'src/class-publicize-base.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool', 'PhanSuspiciousMagicConstant', 'PhanTypeMismatchArgument', 'PhanTypeMismatchArgumentNullable', 'PhanTypeMismatchArgumentNullableInternal', 'PhanTypeMismatchDimFetch'],
         'src/class-publicize-ui.php' => ['PhanPluginDuplicateExpressionAssignmentOperation', 'PhanTypeMismatchReturnProbablyReal'],
-        'src/class-publicize.php' => ['PhanParamSignatureMismatch', 'PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgument', 'PhanTypeMissingReturn'],
+        'src/class-publicize.php' => ['PhanParamSignatureMismatch', 'PhanTypeMismatchArgument', 'PhanTypeMissingReturn'],
         'src/class-rest-controller.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchReturnProbablyReal'],
         'src/rest-api/class-connections-controller.php' => ['PhanPluginMixedKeyNoKey', 'PhanTypeSuspiciousNonTraversableForeach'],
         'src/rest-api/class-connections-post-field.php' => ['PhanPluginDuplicateConditionalNullCoalescing'],

diff --git a/projects/packages/publicize/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/publicize/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/publicize/src/class-publicize.php b/projects/packages/publicize/src/class-publicize.php
@@ -653,8 +653,8 @@ public function test_connection( $service_name, $connection ) {
 
 		$error_data = array(
 			'user_can_refresh' => $user_can_refresh,
-			'refresh_text'     => $refresh_text,
-			'refresh_url'      => $refresh_url,
+			'refresh_text'     => $refresh_text ?? null,
+			'refresh_url'      => $refresh_url ?? null,
 		);
 
 		$this->test_connection_results[ $id ] = new WP_Error( $connection_error_code, $connection_test_message, $error_data );

diff --git a/projects/packages/search/.phan/baseline.php b/projects/packages/search/.phan/baseline.php
@@ -20,7 +20,6 @@
     // PhanImpossibleCondition : 2 occurrences
     // PhanDeprecatedPartiallySupportedCallable : 1 occurrence
     // PhanPluginSimplifyExpressionBool : 1 occurrence
-    // PhanPossiblyUndeclaredVariable : 1 occurrence
     // PhanTypeInvalidDimOffset : 1 occurrence
     // PhanTypeMismatchDeclaredParamNullable : 1 occurrence
     // PhanTypeMismatchDefault : 1 occurrence
@@ -38,7 +37,7 @@
         'src/classic-search/class-classic-search.php' => ['PhanTypeInvalidDimOffset', 'PhanTypeMismatchDeclaredParamNullable', 'PhanTypeMismatchProperty', 'PhanTypeMismatchReturn', 'PhanTypePossiblyInvalidDimOffset'],
         'src/customizer/customize-controls/class-excluded-post-types-control.php' => ['PhanTypeMismatchReturnProbablyReal'],
         'src/instant-search/class-instant-search.php' => ['PhanTypeMismatchProperty', 'PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal'],
-        'src/widgets/class-search-widget.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgument'],
+        'src/widgets/class-search-widget.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchArgument'],
         'src/wpes/class-query-builder.php' => ['PhanImpossibleCondition', 'PhanTypeMismatchDimAssignment', 'PhanTypeMismatchReturnProbablyReal'],
         'tests/php/Helpers_Test.php' => ['PhanPluginMixedKeyNoKey', 'PhanTypeMismatchArgument'],
         'tests/php/Plan_Test.php' => ['PhanDeprecatedFunction', 'PhanTypeMismatchArgumentProbablyReal'],

diff --git a/projects/packages/search/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/search/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/search/src/widgets/class-search-widget.php b/projects/packages/search/src/widgets/class-search-widget.php
@@ -325,7 +325,7 @@ public function widget( $args, $instance ) {
 	 * @since 8.3.0
 	 */
 	public function widget_non_instant( $args, $instance ) {
-		$display_filters = false;
+		$filters = array();
 
 		// Search instance must have been initialized before widget render.
 		if ( is_search() ) {
@@ -339,13 +339,9 @@ public function widget_non_instant( $args, $instance ) {
 			if ( ! Helper::are_filters_by_widget_disabled() && ! $this->should_display_sitewide_filters() ) {
 				$filters = array_filter( $filters, array( $this, 'is_for_current_widget' ) );
 			}
-
-			if ( ! empty( $filters ) ) {
-				$display_filters = true;
-			}
 		}
 
-		if ( ! $display_filters && empty( $instance['search_box_enabled'] ) && empty( $instance['user_sort_enabled'] ) ) {
+		if ( ! $filters && empty( $instance['search_box_enabled'] ) && empty( $instance['user_sort_enabled'] ) ) {
 			return;
 		}
 
@@ -400,7 +396,7 @@ public function widget_non_instant( $args, $instance ) {
 			<?php
 		endif;
 
-		if ( $display_filters ) {
+		if ( $filters ) {
 			/**
 			 * Responsible for rendering filters to narrow down search results.
 			 *
@@ -445,8 +441,6 @@ public function widget_instant( $args, $instance ) {
 			$filters = array_filter( $filters, array( $this, 'is_for_current_widget' ) );
 		}
 
-		$display_filters = ! empty( $filters );
-
 		$title = ! empty( $instance['title'] ) ? $instance['title'] : '';
 
 		/** This filter is documented in core/src/wp-includes/default-widgets.php */
@@ -473,7 +467,7 @@ public function widget_instant( $args, $instance ) {
 
 		Template_Tags::render_widget_search_form( array(), '', '' );
 
-		if ( $display_filters ) {
+		if ( $filters ) {
 			/**
 			 * Responsible for rendering filters to narrow down search results.
 			 *

diff --git a/projects/packages/sync/.phan/baseline.php b/projects/packages/sync/.phan/baseline.php
@@ -11,13 +11,12 @@
     // # Issue statistics:
     // PhanTypeMismatchArgument : 40+ occurrences
     // PhanPluginDuplicateConditionalNullCoalescing : 30+ occurrences
-    // PhanTypeMismatchReturnProbablyReal : 30+ occurrences
+    // PhanTypeMismatchReturnProbablyReal : 25+ occurrences
     // PhanTypeMismatchReturn : 20+ occurrences
     // PhanParamSignatureMismatch : 10+ occurrences
     // PhanTypeMismatchArgumentProbablyReal : 10+ occurrences
     // PhanPluginSimplifyExpressionBool : 9 occurrences
     // PhanPluginDuplicateSwitchCaseLooseEquality : 6 occurrences
-    // PhanPossiblyUndeclaredVariable : 4 occurrences
     // PhanTypeExpectedObjectPropAccess : 4 occurrences
     // PhanNonClassMethodCall : 3 occurrences
     // PhanTypeArraySuspiciousNullable : 3 occurrences
@@ -50,13 +49,13 @@
         'src/class-rest-sender.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchArgumentProbablyReal'],
         'src/class-sender.php' => ['PhanNonClassMethodCall', 'PhanPluginDuplicateConditionalNullCoalescing', 'PhanTypeMismatchArgument', 'PhanTypeMismatchArgumentProbablyReal', 'PhanTypeMismatchProperty', 'PhanTypeMismatchReturnProbablyReal'],
         'src/class-server.php' => ['PhanTypeMismatchDeclaredParam', 'PhanTypeMismatchReturnProbablyReal'],
-        'src/class-settings.php' => ['PhanPossiblyUndeclaredVariable', 'PhanTypeMismatchArgumentProbablyReal'],
+        'src/class-settings.php' => ['PhanTypeMismatchArgumentProbablyReal'],
         'src/class-utils.php' => ['PhanTypeExpectedObjectPropAccess'],
         'src/modules/class-callables.php' => ['PhanParamSignatureMismatch', 'PhanTypeArraySuspicious', 'PhanTypeMismatchArgument'],
         'src/modules/class-comments.php' => ['PhanTypeMismatchReturn', 'PhanTypeMismatchReturnProbablyReal'],
         'src/modules/class-constants.php' => ['PhanParamSignatureMismatch'],
         'src/modules/class-full-sync-immediately.php' => ['PhanPluginSimplifyExpressionBool', 'PhanTypeMismatchReturn'],
-        'src/modules/class-full-sync.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool', 'PhanPossiblyUndeclaredVariable'],
+        'src/modules/class-full-sync.php' => ['PhanPluginDuplicateConditionalNullCoalescing', 'PhanPluginSimplifyExpressionBool'],
         'src/modules/class-module.php' => ['PhanTypeMismatchArgument', 'PhanTypeMismatchReturnProbablyReal'],
         'src/modules/class-network-options.php' => ['PhanParamSignatureMismatch'],
         'src/modules/class-options.php' => ['PhanParamSignatureMismatch', 'PhanTypeMismatchReturnProbablyReal'],

diff --git a/projects/packages/sync/changelog/fix-phan-PhanPossiblyUndeclaredVariable b/projects/packages/sync/changelog/fix-phan-PhanPossiblyUndeclaredVariable
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Phan: Address PhanPossiblyUndeclaredVariable violations.
diff --git a/projects/packages/sync/src/class-settings.php b/projects/packages/sync/src/class-settings.php
@@ -283,6 +283,7 @@ public static function update_settings( $new_settings ) {
 			/**
 			 * Regular option update and handling
 			 */
+			$updated = false;
 			if ( self::is_network_setting( $setting ) ) {
 				if ( is_multisite() && is_main_site() ) {
 					$updated = update_site_option( self::SETTINGS_OPTION_PREFIX . $setting, $value );

diff --git a/projects/packages/sync/src/modules/class-full-sync.php b/projects/packages/sync/src/modules/class-full-sync.php
@@ -340,6 +340,10 @@ public function get_range( $type ) {
 				$id        = 'comment_ID';
 				$where_sql = Settings::get_comments_filter_sql();
 				break;
+			default:
+				// This should never be reached due to the guard condition above,
+				// but Phan complains so let's make it happy.
+				return array();
 		}
 
 		// TODO: Call $wpdb->prepare on the following query.