Add inline object caching to HPPS repositories

AGENTS.md

@@ -35,6 +35,7 @@ Composer production dependencies that may conflict with other plugins are scoped
 
 - **CRITICAL: WordPress filters persist between test cases.** Always remove filters added during a test in `tearDown()` or the test will leak state into other tests.
 - **Use `assertSame()` over `assertEquals()`** — strict type + equality comparison.
+- **Use assertion messages when a test has multiple assertions** — pass the `$message` parameter to differentiate which assertion failed (e.g., `self::assertSame( 1, $id, 'ID should be 1' )`).
 - **Text domain is `sensei-lms`** (not `sensei`). All user-facing strings MUST use this.
 - **Never concatenate translatable strings** — use `sprintf()` with placeholders.
 - **Never use `extract()`, `eval()`, or `create_function()`.**
@@ -45,6 +46,7 @@ Composer production dependencies that may conflict with other plugins are scoped
 - **Branch naming**: `type/description` — e.g. `fix/course-average-query`, `add/show-tailored-course-outline`, `feature/ai-make-quiz`
 - **PRs**: Must reference an issue (`Resolves #123`), include testing instructions, and follow `.github/PULL_REQUEST_TEMPLATE.md`.
 - **Changelogs**: Every user-facing change MUST have a changelog entry before opening a PR. Run `npm run changelog` (entries stored in `changelog/`).
+- Use the `$$next-version$$` placeholder for the `@since` parameter.
 
 ## Boundaries
 

changelog/add-hpps-inline-caching

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+Add object caching to HPPS (High-Performance Progress Storage) repositories

includes/internal/quiz-submission/answer/repositories/class-tables-based-answer-repository.php

@@ -9,6 +9,8 @@
 
 use DateTimeImmutable;
 use DateTimeZone;
+use Sensei\Internal\Cache_Prefix;
+use Sensei\Internal\Services\Progress_Storage_Settings;
 use Sensei\Internal\Quiz_Submission\Answer\Models\Answer_Interface;
 use Sensei\Internal\Quiz_Submission\Answer\Models\Tables_Based_Answer;
 use Sensei\Internal\Quiz_Submission\Submission\Models\Submission_Interface;
@@ -26,6 +28,17 @@
  * @since 4.16.1
  */
 class Tables_Based_Answer_Repository implements Answer_Repository_Interface {
+	use Cache_Prefix;
+
+	/**
+	 * Cache group for quiz answers.
+	 *
+	 * @since $$next-version$$
+	 *
+	 * @var string
+	 */
+	private const CACHE_GROUP = 'sensei_quiz_answers';
+
 	/**
 	 * WordPress database object.
 	 *
@@ -102,14 +115,20 @@ public function create( Submission_Interface $submission, int $question_id, stri
 			]
 		);
 
-		return new Tables_Based_Answer(
+		$answer = new Tables_Based_Answer(
 			$this->wpdb->insert_id,
 			$submission_id,
 			$question_id,
 			$value,
 			$current_datetime,
 			$current_datetime
 		);
+
+		if ( $this->wpdb->insert_id && Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_delete( self::get_prefixed_key( $this->get_cache_key( $submission_id ), self::CACHE_GROUP ), self::CACHE_GROUP );
+		}
+
+		return $answer;
 	}
 
 	/**
@@ -135,6 +154,15 @@ public function get_all( int $submission_id ): array {
 		 */
 		$submission_id = (int) apply_filters( 'sensei_quiz_answer_get_all_submission_id', $submission_id, 'tables' );
 
+		$cache_key = $this->get_cache_key( $submission_id );
+
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			$cached = wp_cache_get( self::get_prefixed_key( $cache_key, self::CACHE_GROUP ), self::CACHE_GROUP );
+			if ( false !== $cached ) {
+				return $cached;
+			}
+		}
+
 		$query = $this->wpdb->prepare(
 			// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
 			"SELECT * FROM {$this->get_table_name()} WHERE submission_id = %d",
@@ -154,6 +182,10 @@ public function get_all( int $submission_id ): array {
 			);
 		}
 
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_set( self::get_prefixed_key( $cache_key, self::CACHE_GROUP ), $answers, self::CACHE_GROUP );
+		}
+
 		return $answers;
 	}
 
@@ -187,6 +219,22 @@ public function delete_all( Submission_Interface $submission ): void {
 				'%d',
 			]
 		);
+
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_delete( self::get_prefixed_key( $this->get_cache_key( $submission_id ), self::CACHE_GROUP ), self::CACHE_GROUP );
+		}
+	}
+
+	/**
+	 * Get the cache key for quiz answers by submission.
+	 *
+	 * @since $$next-version$$
+	 *
+	 * @param int $submission_id The submission ID.
+	 * @return string The cache key.
+	 */
+	private function get_cache_key( int $submission_id ): string {
+		return (string) $submission_id;
 	}
 
 	/**

includes/internal/quiz-submission/grade/repositories/class-tables-based-grade-repository.php

@@ -11,6 +11,8 @@
 	exit;
 }
 
+use Sensei\Internal\Cache_Prefix;
+use Sensei\Internal\Services\Progress_Storage_Settings;
 use Sensei\Internal\Quiz_Submission\Answer\Models\Answer_Interface;
 use Sensei\Internal\Quiz_Submission\Grade\Models\Tables_Based_Grade;
 use Sensei\Internal\Quiz_Submission\Grade\Models\Grade_Interface;
@@ -25,6 +27,17 @@
  * @since 4.16.1
  */
 class Tables_Based_Grade_Repository implements Grade_Repository_Interface {
+	use Cache_Prefix;
+
+	/**
+	 * Cache group for quiz grades.
+	 *
+	 * @since $$next-version$$
+	 *
+	 * @var string
+	 */
+	private const CACHE_GROUP = 'sensei_quiz_grades';
+
 	/**
 	 * WordPress database object.
 	 *
@@ -105,7 +118,7 @@ public function create( Submission_Interface $submission, Answer_Interface $answ
 			]
 		);
 
-		return new Tables_Based_Grade(
+		$grade = new Tables_Based_Grade(
 			$this->wpdb->insert_id,
 			$answer_id,
 			$question_id,
@@ -114,6 +127,12 @@ public function create( Submission_Interface $submission, Answer_Interface $answ
 			$current_date,
 			$current_date
 		);
+
+		if ( $this->wpdb->insert_id && Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_delete( self::get_prefixed_key( $this->get_cache_key( $submission->get_id() ), self::CACHE_GROUP ), self::CACHE_GROUP );
+		}
+
+		return $grade;
 	}
 
 	/**
@@ -139,8 +158,21 @@ public function get_all( int $submission_id ): array {
 		 */
 		$submission_id = (int) apply_filters( 'sensei_quiz_grade_get_all_submission_id', $submission_id, 'tables' );
 
+		$cache_key = $this->get_cache_key( $submission_id );
+
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			$cached = wp_cache_get( self::get_prefixed_key( $cache_key, self::CACHE_GROUP ), self::CACHE_GROUP );
+			if ( false !== $cached ) {
+				return $cached;
+			}
+		}
+
 		$answer_ids = $this->get_answer_ids_by_submission_id( $submission_id );
 		if ( empty( $answer_ids ) ) {
+			if ( Progress_Storage_Settings::is_cache_enabled() ) {
+				wp_cache_set( self::get_prefixed_key( $cache_key, self::CACHE_GROUP ), array(), self::CACHE_GROUP );
+			}
+
 			return [];
 		}
 
@@ -162,6 +194,10 @@ public function get_all( int $submission_id ): array {
 			);
 		}
 
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_set( self::get_prefixed_key( $cache_key, self::CACHE_GROUP ), $grades, self::CACHE_GROUP );
+		}
+
 		return $grades;
 	}
 
@@ -177,6 +213,10 @@ public function save_many( Submission_Interface $submission, array $grades ): vo
 		foreach ( $grades as $grade ) {
 			$this->save( $grade );
 		}
+
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_delete( self::get_prefixed_key( $this->get_cache_key( $submission->get_id() ), self::CACHE_GROUP ), self::CACHE_GROUP );
+		}
 	}
 
 	/**
@@ -209,6 +249,10 @@ public function delete_all( Submission_Interface $submission ): void {
 		$delete_query = 'DELETE FROM ' . $this->get_table_name() . ' WHERE answer_id IN (' . $placeholders . ')';
 		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
 		$this->wpdb->query( $this->wpdb->prepare( $delete_query, ...$answer_ids ) );
+
+		if ( Progress_Storage_Settings::is_cache_enabled() ) {
+			wp_cache_delete( self::get_prefixed_key( $this->get_cache_key( $submission_id ), self::CACHE_GROUP ), self::CACHE_GROUP );
+		}
 	}
 
 	/**
@@ -240,10 +284,23 @@ private function save( Grade_Interface $grade ): void {
 		);
 	}
 
+	/**
+	 * Get the cache key for quiz grades by submission.
+	 *
+	 * @since $$next-version$$
+	 *
+	 * @param int $submission_id The submission ID.
+	 * @return string The cache key.
+	 */
+	private function get_cache_key( int $submission_id ): string {
+		return (string) $submission_id;
+	}
+
 	/**
 	 * Get all answer IDs for a submission.
 	 *
 	 * @param int $submission_id The submission ID.
+	 * @return array The answer IDs.
 	 */
 	private function get_answer_ids_by_submission_id( int $submission_id ): array {
 		$answers_query = $this->wpdb->prepare(

includes/internal/quiz-submission/submission/repositories/class-comments-based-submission-repository.php

@@ -50,7 +50,7 @@ public function create( int $quiz_id, int $user_id, float $final_grade = null ):
 		 * @param {int} $quiz_id The quiz ID.
 		 * @return {int} The quiz ID.
 		*/
-		$quiz_id = apply_filters( 'sensei_quiz_submission_create_quiz_id', $quiz_id );
+		$quiz_id = (int) apply_filters( 'sensei_quiz_submission_create_quiz_id', $quiz_id );
 
 		$status_comment = $this->get_status_comment( $quiz_id, $user_id );
 
@@ -96,7 +96,7 @@ public function get_or_create( int $quiz_id, int $user_id, float $final_grade =
 		 * @param {int} $quiz_id The quiz ID.
 		 * @return {int} The quiz ID.
 		 */
-		$quiz_id = apply_filters( 'sensei_quiz_submission_get_or_create_quiz_id', $quiz_id );
+		$quiz_id = (int) apply_filters( 'sensei_quiz_submission_get_or_create_quiz_id', $quiz_id );
 
 		$submission = $this->get( $quiz_id, $user_id );
 
@@ -128,7 +128,7 @@ public function get( int $quiz_id, int $user_id ): ?Submission_Interface {
 		 * @param {int} $quiz_id The quiz ID.
 		 * @return {int} The quiz ID.
 		 */
-		$quiz_id = apply_filters( 'sensei_quiz_submission_get_quiz_id', $quiz_id );
+		$quiz_id = (int) apply_filters( 'sensei_quiz_submission_get_quiz_id', $quiz_id );
 
 		$status_comment = $this->get_status_comment( $quiz_id, $user_id );