Merge CommentStoreBase into CommentStore

Bug: T343558
Change-Id: I74cd68b7689f750d9300141575506910878f1802

2 files changed, 382 insertions, 412 deletions

diff --git a/includes/CommentStore/CommentStore.php b/includes/CommentStore/CommentStore.php
index 261202e4c310..f9591b7eeb98 100644
--- a/includes/CommentStore/CommentStore.php
+++ b/includes/CommentStore/CommentStore.php
@@ -20,6 +20,15 @@
 
 namespace MediaWiki\CommentStore;
 
+use FormatJson;
+use InvalidArgumentException;
+use Language;
+use MediaWiki\Language\RawMessage;
+use Message;
+use OverflowException;
+use stdClass;
+use Wikimedia\Rdbms\IDatabase;
+
 /**
  * @defgroup CommentStore CommentStore
  *
@@ -38,7 +47,379 @@ namespace MediaWiki\CommentStore;
  * @ingroup CommentStore
  * @since 1.30
  */
-class CommentStore extends CommentStoreBase {
+class CommentStore {
+
+	/**
+	 * Maximum length of a comment in UTF-8 characters. Longer comments will be truncated.
+	 * @note This must be at least 255 and not greater than floor( MAX_DATA_LENGTH / 4 ).
+	 */
+	public const COMMENT_CHARACTER_LIMIT = 500;
+
+	/**
+	 * Maximum length of serialized data in bytes. Longer data will result in an exception.
+	 * @note This value is determined by the size of the underlying database field,
+	 *  currently BLOB in MySQL/MariaDB.
+	 */
+	public const MAX_DATA_LENGTH = 65535;
+
+	/** @var array[] Cache for `self::getJoin()` */
+	private $joinCache = [];
+
+	/** @var Language Language to use for comment truncation */
+	private $lang;
+
+	/**
+	 * @param Language $lang Language to use for comment truncation. Defaults
+	 *  to content language.
+	 */
+	public function __construct( Language $lang ) {
+		$this->lang = $lang;
+	}
+
+	/**
+	 * Get SELECT fields for the comment key
+	 *
+	 * Each resulting row should be passed to `self::getCommentLegacy()` to get the
+	 * actual comment.
+	 *
+	 * @note Use of this method may require a subsequent database query to
+	 *  actually fetch the comment. If possible, use `self::getJoin()` instead.
+	 *
+	 * @since 1.30
+	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @return string[] to include in the `$vars` to `IDatabase->select()`. All
+	 *  fields are aliased, so `+` is safe to use.
+	 */
+	public function getFields( $key ) {
+		return [ "{$key}_id" => "{$key}_id" ];
+	}
+
+	/**
+	 * Get SELECT fields and joins for the comment key
+	 *
+	 * Each resulting row should be passed to `self::getComment()` to get the
+	 * actual comment.
+	 *
+	 * @since 1.30
+	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @return array[] With three keys:
+	 *   - tables: (string[]) to include in the `$table` to `IDatabase->select()` or `SelectQueryBuilder::tables`
+	 *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()` or `SelectQueryBuilder::fields`
+	 *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()` or `SelectQueryBuilder::joinConds`
+	 *  All tables, fields, and joins are aliased, so `+` is safe to use.
+	 * @phan-return array{tables:string[],fields:string[],joins:array}
+	 */
+	public function getJoin( $key ) {
+		if ( !array_key_exists( $key, $this->joinCache ) ) {
+			$tables = [];
+			$fields = [];
+			$joins = [];
+
+			$alias = "comment_$key";
+			$tables[$alias] = 'comment';
+			$joins[$alias] = [ 'JOIN', "{$alias}.comment_id = {$key}_id" ];
+
+			$fields["{$key}_text"] = "{$alias}.comment_text";
+			$fields["{$key}_data"] = "{$alias}.comment_data";
+			$fields["{$key}_cid"] = "{$alias}.comment_id";
+
+			$this->joinCache[$key] = [
+				'tables' => $tables,
+				'fields' => $fields,
+				'joins' => $joins,
+			];
+		}
+
+		return $this->joinCache[$key];
+	}
+
+	/**
+	 * Extract the comment from a row
+	 *
+	 * Shared implementation for getComment() and getCommentLegacy()
+	 *
+	 * @param IDatabase|null $db Database handle for getCommentLegacy(), or null for getComment()
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @param stdClass|array $row
+	 * @param bool $fallback
+	 * @return CommentStoreComment
+	 */
+	private function getCommentInternal( ?IDatabase $db, $key, $row, $fallback = false ) {
+		$row = (array)$row;
+		if ( array_key_exists( "{$key}_text", $row ) && array_key_exists( "{$key}_data", $row ) ) {
+			$cid = $row["{$key}_cid"] ?? null;
+			$text = $row["{$key}_text"];
+			$data = $row["{$key}_data"];
+		} else {
+			$row2 = null;
+			if ( array_key_exists( "{$key}_id", $row ) ) {
+				if ( !$db ) {
+					throw new InvalidArgumentException(
+						"\$row does not contain fields needed for comment $key and getComment(), but "
+						. "does have fields for getCommentLegacy()"
+					);
+				}
+				$id = $row["{$key}_id"];
+				$row2 = $db->newSelectQueryBuilder()
+					->select( [ 'comment_id', 'comment_text', 'comment_data' ] )
+					->from( 'comment' )
+					->where( [ 'comment_id' => $id ] )
+					->caller( __METHOD__ )->fetchRow();
+			}
+			if ( $row2 === null && $fallback && isset( $row[$key] ) ) {
+				wfLogWarning( "Using deprecated fallback handling for comment $key" );
+				$row2 = (object)[ 'comment_text' => $row[$key], 'comment_data' => null ];
+			}
+			if ( $row2 === null ) {
+				throw new InvalidArgumentException( "\$row does not contain fields needed for comment $key" );
+			}
+
+			if ( $row2 ) {
+				$cid = $row2->comment_id;
+				$text = $row2->comment_text;
+				$data = $row2->comment_data;
+			} else {
+				// @codeCoverageIgnoreStart
+				// @phan-suppress-next-line PhanPossiblyUndeclaredVariable $id is set when $row2 is okay
+				wfLogWarning( "Missing comment row for $key, id=$id" );
+				$cid = null;
+				$text = '';
+				$data = null;
+				// @codeCoverageIgnoreEnd
+			}
+		}
+
+		$msg = null;
+		if ( $data !== null ) {
+			$data = FormatJson::decode( $data, true );
+			if ( !is_array( $data ) ) {
+				// @codeCoverageIgnoreStart
+				wfLogWarning( "Invalid JSON object in comment: $data" );
+				$data = null;
+				// @codeCoverageIgnoreEnd
+			} else {
+				if ( isset( $data['_message'] ) ) {
+					$msg = self::decodeMessage( $data['_message'] )
+						->setInterfaceMessageFlag( true );
+				}
+				if ( !empty( $data['_null'] ) ) {
+					$data = null;
+				} else {
+					foreach ( $data as $k => $v ) {
+						if ( substr( $k, 0, 1 ) === '_' ) {
+							unset( $data[$k] );
+						}
+					}
+				}
+			}
+		}
+
+		return new CommentStoreComment( $cid, $text, $msg, $data );
+	}
+
+	/**
+	 * Extract the comment from a row
+	 *
+	 * Use `self::getJoin()` to ensure the row contains the needed data.
+	 *
+	 * If you need to fake a comment in a row for some reason, set fields
+	 * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
+	 *
+	 * @since 1.30
+	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @param stdClass|array|null $row Result row.
+	 * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
+	 * @return CommentStoreComment
+	 */
+	public function getComment( $key, $row = null, $fallback = false ) {
+		if ( $row === null ) {
+			// @codeCoverageIgnoreStart
+			throw new InvalidArgumentException( '$row must not be null' );
+			// @codeCoverageIgnoreEnd
+		}
+		return $this->getCommentInternal( null, $key, $row, $fallback );
+	}
+
+	/**
+	 * Extract the comment from a row, with legacy lookups.
+	 *
+	 * If `$row` might have been generated using `self::getFields()` rather
+	 * than `self::getJoin()`, use this. Prefer `self::getComment()` if you
+	 * know callers used `self::getJoin()` for the row fetch.
+	 *
+	 * If you need to fake a comment in a row for some reason, set fields
+	 * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
+	 *
+	 * @since 1.30
+	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
+	 * @param IDatabase $db Database handle to use for lookup
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @param stdClass|array|null $row Result row.
+	 * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
+	 * @return CommentStoreComment
+	 */
+	public function getCommentLegacy( IDatabase $db, $key, $row = null, $fallback = false ) {
+		if ( $row === null ) {
+			// @codeCoverageIgnoreStart
+			throw new InvalidArgumentException( '$row must not be null' );
+			// @codeCoverageIgnoreEnd
+		}
+		return $this->getCommentInternal( $db, $key, $row, $fallback );
+	}
+
+	/**
+	 * Create a new CommentStoreComment, inserting it into the database if necessary
+	 *
+	 * If a comment is going to be passed to `self::insert()` or the like
+	 * multiple times, it will be more efficient to pass a CommentStoreComment
+	 * once rather than making `self::insert()` do it every time through.
+	 *
+	 * @note When passing a CommentStoreComment, this may set `$comment->id` if
+	 *  it's not already set. If `$comment->id` is already set, it will not be
+	 *  verified that the specified comment actually exists or that it
+	 *  corresponds to the comment text, message, and/or data in the
+	 *  CommentStoreComment.
+	 * @param IDatabase $dbw Database handle to insert on. Unused if `$comment`
+	 *  is a CommentStoreComment and `$comment->id` is set.
+	 * @param string|Message|CommentStoreComment $comment Comment text or Message object, or
+	 *  a CommentStoreComment.
+	 * @param array|null $data Structured data to store. Keys beginning with '_' are reserved.
+	 *  Ignored if $comment is a CommentStoreComment.
+	 * @return CommentStoreComment
+	 */
+	public function createComment( IDatabase $dbw, $comment, array $data = null ) {
+		$comment = CommentStoreComment::newUnsavedComment( $comment, $data );
+
+		# Truncate comment in a Unicode-sensitive manner
+		$comment->text = $this->lang->truncateForVisual( $comment->text, self::COMMENT_CHARACTER_LIMIT );
+
+		if ( !$comment->id ) {
+			$dbData = $comment->data;
+			if ( !$comment->message instanceof RawMessage ) {
+				$dbData ??= [ '_null' => true ];
+				$dbData['_message'] = self::encodeMessage( $comment->message );
+			}
+			if ( $dbData !== null ) {
+				$dbData = FormatJson::encode( (object)$dbData, false, FormatJson::ALL_OK );
+				$len = strlen( $dbData );
+				if ( $len > self::MAX_DATA_LENGTH ) {
+					$max = self::MAX_DATA_LENGTH;
+					throw new OverflowException( "Comment data is too long ($len bytes, maximum is $max)" );
+				}
+			}
+
+			$hash = self::hash( $comment->text, $dbData );
+			$commentId = $dbw->newSelectQueryBuilder()
+				->select( 'comment_id' )
+				->from( 'comment' )
+				->where( [
+					'comment_hash' => $hash,
+					'comment_text' => $comment->text,
+					'comment_data' => $dbData,
+				] )
+				->caller( __METHOD__ )->fetchField();
+			if ( !$commentId ) {
+				$dbw->newInsertQueryBuilder()
+					->insert( 'comment' )
+					->row( [ 'comment_hash' => $hash, 'comment_text' => $comment->text, 'comment_data' => $dbData ] )
+					->caller( __METHOD__ )->execute();
+				$commentId = $dbw->insertId();
+			}
+			$comment->id = (int)$commentId;
+		}
+
+		return $comment;
+	}
+
+	/**
+	 * Insert a comment in preparation for a row that references it
+	 *
+	 * @note It's recommended to include both the call to this method and the
+	 *  row insert in the same transaction.
+	 *
+	 * @since 1.30
+	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
+	 * @param IDatabase $dbw Database handle to insert on
+	 * @param string $key A key such as "rev_comment" identifying the comment
+	 *  field being fetched.
+	 * @param string|Message|CommentStoreComment|null $comment As for `self::createComment()`
+	 * @param array|null $data As for `self::createComment()`
+	 * @return array Fields for the insert or update
+	 */
+	public function insert( IDatabase $dbw, $key, $comment = null, $data = null ) {
+		if ( $comment === null ) {
+			// @codeCoverageIgnoreStart
+			throw new InvalidArgumentException( '$comment can not be null' );
+			// @codeCoverageIgnoreEnd
+		}
+
+		$comment = $this->createComment( $dbw, $comment, $data );
+		return [ "{$key}_id" => $comment->id ];
+	}
+
+	/**
+	 * Encode a Message as a PHP data structure
+	 * @param Message $msg
+	 * @return array
+	 */
+	private static function encodeMessage( Message $msg ) {
+		$key = count( $msg->getKeysToTry() ) > 1 ? $msg->getKeysToTry() : $msg->getKey();
+		$params = $msg->getParams();
+		foreach ( $params as &$param ) {
+			if ( $param instanceof Message ) {
+				$param = [
+					'message' => self::encodeMessage( $param )
+				];
+			}
+		}
+		array_unshift( $params, $key );
+		return $params;
+	}
+
+	/**
+	 * Decode a message that was encoded by self::encodeMessage()
+	 * @param array $data
+	 * @return Message
+	 */
+	private static function decodeMessage( $data ) {
+		$key = array_shift( $data );
+		foreach ( $data as &$param ) {
+			if ( is_object( $param ) ) {
+				$param = (array)$param;
+			}
+			if ( is_array( $param ) && count( $param ) === 1 && isset( $param['message'] ) ) {
+				$param = self::decodeMessage( $param['message'] );
+			}
+		}
+		return new Message( $key, $data );
+	}
+
+	/**
+	 * Hashing function for comment storage
+	 * @param string $text Comment text
+	 * @param string|null $data Comment data
+	 * @return int 32-bit signed integer
+	 */
+	public static function hash( $text, $data ) {
+		$hash = crc32( $text ) ^ crc32( (string)$data );
+
+		// 64-bit PHP returns an unsigned CRC, change it to signed for
+		// insertion into the database.
+		if ( $hash >= 0x80000000 ) {
+			$hash |= -1 << 32;
+		}
+
+		return $hash;
+	}
+
 }
 
 /**
diff --git a/includes/CommentStore/CommentStoreBase.php b/includes/CommentStore/CommentStoreBase.php
deleted file mode 100644
index 2e8e4a1f1922..000000000000
--- a/includes/CommentStore/CommentStoreBase.php
+++ /dev/null
@@ -1,411 +0,0 @@
-<?php
-/**
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- * http://www.gnu.org/copyleft/gpl.html
- *
- * @file
- */
-
-namespace MediaWiki\CommentStore;
-
-use FormatJson;
-use InvalidArgumentException;
-use Language;
-use MediaWiki\Language\RawMessage;
-use Message;
-use OverflowException;
-use stdClass;
-use Wikimedia\Rdbms\IDatabase;
-
-/*
- * Handle database storage of comments such as edit summaries and log reasons.
- *
- * @ingroup CommentStore
- * @since 1.40
- */
-class CommentStoreBase {
-
-	/**
-	 * Maximum length of a comment in UTF-8 characters. Longer comments will be truncated.
-	 * @note This must be at least 255 and not greater than floor( MAX_DATA_LENGTH / 4 ).
-	 */
-	public const COMMENT_CHARACTER_LIMIT = 500;
-
-	/**
-	 * Maximum length of serialized data in bytes. Longer data will result in an exception.
-	 * @note This value is determined by the size of the underlying database field,
-	 *  currently BLOB in MySQL/MariaDB.
-	 */
-	public const MAX_DATA_LENGTH = 65535;
-
-	/** @var array[] Cache for `self::getJoin()` */
-	private $joinCache = [];
-
-	/** @var Language Language to use for comment truncation */
-	private $lang;
-
-	/**
-	 * @param Language $lang Language to use for comment truncation. Defaults
-	 *  to content language.
-	 */
-	public function __construct( Language $lang ) {
-		$this->lang = $lang;
-	}
-
-	/**
-	 * Get SELECT fields for the comment key
-	 *
-	 * Each resulting row should be passed to `self::getCommentLegacy()` to get the
-	 * actual comment.
-	 *
-	 * @note Use of this method may require a subsequent database query to
-	 *  actually fetch the comment. If possible, use `self::getJoin()` instead.
-	 *
-	 * @since 1.30
-	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @return string[] to include in the `$vars` to `IDatabase->select()`. All
-	 *  fields are aliased, so `+` is safe to use.
-	 */
-	public function getFields( $key ) {
-		return [ "{$key}_id" => "{$key}_id" ];
-	}
-
-	/**
-	 * Get SELECT fields and joins for the comment key
-	 *
-	 * Each resulting row should be passed to `self::getComment()` to get the
-	 * actual comment.
-	 *
-	 * @since 1.30
-	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @return array[] With three keys:
-	 *   - tables: (string[]) to include in the `$table` to `IDatabase->select()` or `SelectQueryBuilder::tables`
-	 *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()` or `SelectQueryBuilder::fields`
-	 *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()` or `SelectQueryBuilder::joinConds`
-	 *  All tables, fields, and joins are aliased, so `+` is safe to use.
-	 * @phan-return array{tables:string[],fields:string[],joins:array}
-	 */
-	public function getJoin( $key ) {
-		if ( !array_key_exists( $key, $this->joinCache ) ) {
-			$tables = [];
-			$fields = [];
-			$joins = [];
-
-			$alias = "comment_$key";
-			$tables[$alias] = 'comment';
-			$joins[$alias] = [ 'JOIN', "{$alias}.comment_id = {$key}_id" ];
-
-			$fields["{$key}_text"] = "{$alias}.comment_text";
-			$fields["{$key}_data"] = "{$alias}.comment_data";
-			$fields["{$key}_cid"] = "{$alias}.comment_id";
-
-			$this->joinCache[$key] = [
-				'tables' => $tables,
-				'fields' => $fields,
-				'joins' => $joins,
-			];
-		}
-
-		return $this->joinCache[$key];
-	}
-
-	/**
-	 * Extract the comment from a row
-	 *
-	 * Shared implementation for getComment() and getCommentLegacy()
-	 *
-	 * @param IDatabase|null $db Database handle for getCommentLegacy(), or null for getComment()
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @param stdClass|array $row
-	 * @param bool $fallback
-	 * @return CommentStoreComment
-	 */
-	private function getCommentInternal( ?IDatabase $db, $key, $row, $fallback = false ) {
-		$row = (array)$row;
-		if ( array_key_exists( "{$key}_text", $row ) && array_key_exists( "{$key}_data", $row ) ) {
-			$cid = $row["{$key}_cid"] ?? null;
-			$text = $row["{$key}_text"];
-			$data = $row["{$key}_data"];
-		} else {
-			$row2 = null;
-			if ( array_key_exists( "{$key}_id", $row ) ) {
-				if ( !$db ) {
-					throw new InvalidArgumentException(
-						"\$row does not contain fields needed for comment $key and getComment(), but "
-						. "does have fields for getCommentLegacy()"
-					);
-				}
-				$id = $row["{$key}_id"];
-				$row2 = $db->newSelectQueryBuilder()
-					->select( [ 'comment_id', 'comment_text', 'comment_data' ] )
-					->from( 'comment' )
-					->where( [ 'comment_id' => $id ] )
-					->caller( __METHOD__ )->fetchRow();
-			}
-			if ( $row2 === null && $fallback && isset( $row[$key] ) ) {
-				wfLogWarning( "Using deprecated fallback handling for comment $key" );
-				$row2 = (object)[ 'comment_text' => $row[$key], 'comment_data' => null ];
-			}
-			if ( $row2 === null ) {
-				throw new InvalidArgumentException( "\$row does not contain fields needed for comment $key" );
-			}
-
-			if ( $row2 ) {
-				$cid = $row2->comment_id;
-				$text = $row2->comment_text;
-				$data = $row2->comment_data;
-			} else {
-				// @codeCoverageIgnoreStart
-				// @phan-suppress-next-line PhanPossiblyUndeclaredVariable $id is set when $row2 is okay
-				wfLogWarning( "Missing comment row for $key, id=$id" );
-				$cid = null;
-				$text = '';
-				$data = null;
-				// @codeCoverageIgnoreEnd
-			}
-		}
-
-		$msg = null;
-		if ( $data !== null ) {
-			$data = FormatJson::decode( $data, true );
-			if ( !is_array( $data ) ) {
-				// @codeCoverageIgnoreStart
-				wfLogWarning( "Invalid JSON object in comment: $data" );
-				$data = null;
-				// @codeCoverageIgnoreEnd
-			} else {
-				if ( isset( $data['_message'] ) ) {
-					$msg = self::decodeMessage( $data['_message'] )
-						->setInterfaceMessageFlag( true );
-				}
-				if ( !empty( $data['_null'] ) ) {
-					$data = null;
-				} else {
-					foreach ( $data as $k => $v ) {
-						if ( substr( $k, 0, 1 ) === '_' ) {
-							unset( $data[$k] );
-						}
-					}
-				}
-			}
-		}
-
-		return new CommentStoreComment( $cid, $text, $msg, $data );
-	}
-
-	/**
-	 * Extract the comment from a row
-	 *
-	 * Use `self::getJoin()` to ensure the row contains the needed data.
-	 *
-	 * If you need to fake a comment in a row for some reason, set fields
-	 * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
-	 *
-	 * @since 1.30
-	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @param stdClass|array|null $row Result row.
-	 * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
-	 * @return CommentStoreComment
-	 */
-	public function getComment( $key, $row = null, $fallback = false ) {
-		if ( $row === null ) {
-			// @codeCoverageIgnoreStart
-			throw new InvalidArgumentException( '$row must not be null' );
-			// @codeCoverageIgnoreEnd
-		}
-		return $this->getCommentInternal( null, $key, $row, $fallback );
-	}
-
-	/**
-	 * Extract the comment from a row, with legacy lookups.
-	 *
-	 * If `$row` might have been generated using `self::getFields()` rather
-	 * than `self::getJoin()`, use this. Prefer `self::getComment()` if you
-	 * know callers used `self::getJoin()` for the row fetch.
-	 *
-	 * If you need to fake a comment in a row for some reason, set fields
-	 * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
-	 *
-	 * @since 1.30
-	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
-	 * @param IDatabase $db Database handle to use for lookup
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @param stdClass|array|null $row Result row.
-	 * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
-	 * @return CommentStoreComment
-	 */
-	public function getCommentLegacy( IDatabase $db, $key, $row = null, $fallback = false ) {
-		if ( $row === null ) {
-			// @codeCoverageIgnoreStart
-			throw new InvalidArgumentException( '$row must not be null' );
-			// @codeCoverageIgnoreEnd
-		}
-		return $this->getCommentInternal( $db, $key, $row, $fallback );
-	}
-
-	/**
-	 * Create a new CommentStoreComment, inserting it into the database if necessary
-	 *
-	 * If a comment is going to be passed to `self::insert()` or the like
-	 * multiple times, it will be more efficient to pass a CommentStoreComment
-	 * once rather than making `self::insert()` do it every time through.
-	 *
-	 * @note When passing a CommentStoreComment, this may set `$comment->id` if
-	 *  it's not already set. If `$comment->id` is already set, it will not be
-	 *  verified that the specified comment actually exists or that it
-	 *  corresponds to the comment text, message, and/or data in the
-	 *  CommentStoreComment.
-	 * @param IDatabase $dbw Database handle to insert on. Unused if `$comment`
-	 *  is a CommentStoreComment and `$comment->id` is set.
-	 * @param string|Message|CommentStoreComment $comment Comment text or Message object, or
-	 *  a CommentStoreComment.
-	 * @param array|null $data Structured data to store. Keys beginning with '_' are reserved.
-	 *  Ignored if $comment is a CommentStoreComment.
-	 * @return CommentStoreComment
-	 */
-	public function createComment( IDatabase $dbw, $comment, array $data = null ) {
-		$comment = CommentStoreComment::newUnsavedComment( $comment, $data );
-
-		# Truncate comment in a Unicode-sensitive manner
-		$comment->text = $this->lang->truncateForVisual( $comment->text, self::COMMENT_CHARACTER_LIMIT );
-
-		if ( !$comment->id ) {
-			$dbData = $comment->data;
-			if ( !$comment->message instanceof RawMessage ) {
-				$dbData ??= [ '_null' => true ];
-				$dbData['_message'] = self::encodeMessage( $comment->message );
-			}
-			if ( $dbData !== null ) {
-				$dbData = FormatJson::encode( (object)$dbData, false, FormatJson::ALL_OK );
-				$len = strlen( $dbData );
-				if ( $len > self::MAX_DATA_LENGTH ) {
-					$max = self::MAX_DATA_LENGTH;
-					throw new OverflowException( "Comment data is too long ($len bytes, maximum is $max)" );
-				}
-			}
-
-			$hash = self::hash( $comment->text, $dbData );
-			$commentId = $dbw->newSelectQueryBuilder()
-				->select( 'comment_id' )
-				->from( 'comment' )
-				->where( [
-					'comment_hash' => $hash,
-					'comment_text' => $comment->text,
-					'comment_data' => $dbData,
-				] )
-				->caller( __METHOD__ )->fetchField();
-			if ( !$commentId ) {
-				$dbw->newInsertQueryBuilder()
-					->insert( 'comment' )
-					->row( [ 'comment_hash' => $hash, 'comment_text' => $comment->text, 'comment_data' => $dbData ] )
-					->caller( __METHOD__ )->execute();
-				$commentId = $dbw->insertId();
-			}
-			$comment->id = (int)$commentId;
-		}
-
-		return $comment;
-	}
-
-	/**
-	 * Insert a comment in preparation for a row that references it
-	 *
-	 * @note It's recommended to include both the call to this method and the
-	 *  row insert in the same transaction.
-	 *
-	 * @since 1.30
-	 * @since 1.31 Method signature changed, $key parameter added (required since 1.35)
-	 * @param IDatabase $dbw Database handle to insert on
-	 * @param string $key A key such as "rev_comment" identifying the comment
-	 *  field being fetched.
-	 * @param string|Message|CommentStoreComment|null $comment As for `self::createComment()`
-	 * @param array|null $data As for `self::createComment()`
-	 * @return array Fields for the insert or update
-	 */
-	public function insert( IDatabase $dbw, $key, $comment = null, $data = null ) {
-		if ( $comment === null ) {
-			// @codeCoverageIgnoreStart
-			throw new InvalidArgumentException( '$comment can not be null' );
-			// @codeCoverageIgnoreEnd
-		}
-
-		$comment = $this->createComment( $dbw, $comment, $data );
-		return [ "{$key}_id" => $comment->id ];
-	}
-
-	/**
-	 * Encode a Message as a PHP data structure
-	 * @param Message $msg
-	 * @return array
-	 */
-	private static function encodeMessage( Message $msg ) {
-		$key = count( $msg->getKeysToTry() ) > 1 ? $msg->getKeysToTry() : $msg->getKey();
-		$params = $msg->getParams();
-		foreach ( $params as &$param ) {
-			if ( $param instanceof Message ) {
-				$param = [
-					'message' => self::encodeMessage( $param )
-				];
-			}
-		}
-		array_unshift( $params, $key );
-		return $params;
-	}
-
-	/**
-	 * Decode a message that was encoded by self::encodeMessage()
-	 * @param array $data
-	 * @return Message
-	 */
-	private static function decodeMessage( $data ) {
-		$key = array_shift( $data );
-		foreach ( $data as &$param ) {
-			if ( is_object( $param ) ) {
-				$param = (array)$param;
-			}
-			if ( is_array( $param ) && count( $param ) === 1 && isset( $param['message'] ) ) {
-				$param = self::decodeMessage( $param['message'] );
-			}
-		}
-		return new Message( $key, $data );
-	}
-
-	/**
-	 * Hashing function for comment storage
-	 * @param string $text Comment text
-	 * @param string|null $data Comment data
-	 * @return int 32-bit signed integer
-	 */
-	public static function hash( $text, $data ) {
-		$hash = crc32( $text ) ^ crc32( (string)$data );
-
-		// 64-bit PHP returns an unsigned CRC, change it to signed for
-		// insertion into the database.
-		if ( $hash >= 0x80000000 ) {
-			$hash |= -1 << 32;
-		}
-
-		return $hash;
-	}
-
-}