diff --git a/includes/libs/rdbms/database/Database.php b/includes/libs/rdbms/database/Database.php
index d17e2631f9..ec0eea9e10 100644
--- a/includes/libs/rdbms/database/Database.php
+++ b/includes/libs/rdbms/database/Database.php
@@ -3117,6 +3117,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 				null, // emergency limit (default)
 				null, // emergency callback (default)
 				function () use ( $fname ) {
+					print "CriticalSectionProvider runs implicitExitCallback, defined by commenceCriticalSection, sets this->csmError\n" . wfBacktrace();
 					// Mark a critical section as having been aborted by an error
 					$e = new RuntimeException( "A critical section from {$fname} has failed" );
 					$this->csmError = $e;
diff --git a/tests/phpunit/unit/includes/libs/rdbms/database/DatabaseTest.php b/tests/phpunit/unit/includes/libs/rdbms/database/DatabaseTest.php
index d431a13980..5ec2209b7f 100644
--- a/tests/phpunit/unit/includes/libs/rdbms/database/DatabaseTest.php
+++ b/tests/phpunit/unit/includes/libs/rdbms/database/DatabaseTest.php
@@ -848,11 +848,12 @@ class DatabaseTest extends TestCase {
 	public function testCriticalSectionErrorSelect() {
 		$this->expectException( DBTransactionStateError::class );
 
-		$db = TestingAccessWrapper::newFromObject( $this->db );
+		$db = $this->db;
 		try {
 			$this->corruptDbState( $db );
 		} catch ( RuntimeException $e ) {
 			$this->assertEquals( "Unexpected error", $e->getMessage() );
+			print "\n" . __METHOD__ . " caught expected RuntimeException\n";
 		}
 
 		$db->query( "SELECT 1", __METHOD__ );
@@ -901,6 +902,7 @@ class DatabaseTest extends TestCase {
 	}
 
 	private function corruptDbState( $db ) {
+		$db = TestingAccessWrapper::newFromObject( $db );
 		$cs = $db->commenceCriticalSection( __METHOD__ );
 		$this->assertInstanceOf( CriticalSectionScope::class, $cs );
 		throw new RuntimeException( "Unexpected error" );

<?php

class Test {
	public static function testDestructor() {
		$destructorRan = false;
		try {
			self::helper( $destructorRan );
		} catch ( UnexpectedValueException $e ) {
		}

		assert( $destructorRan );
	}

	private static function helper( &$destructorRan ) {
		$cb = static function () use ( &$destructorRan ) {
			$destructorRan = true;
		};
		$class = new class ( $cb ) {
			private $cb;

			public function __construct( $cb ) {
				$this->cb = $cb;
			}

			public function __destruct() {
				( $this->cb )();
			}
		};

		throw new UnexpectedValueException( 'e' );
	}
}

Test::testDestructor();

		$this->assertSame(
			'You have foo (bar).',
			wfMessage( 'new-messages', 'foo', 'bar' )->text()
		);
		$this->assertSame(
		 	'You have foo (bar).',
		 	wfMessage( 'new-messages', [ 'foo', 'bar' ] )->text()
		);

public function preprocess( $text ) {
	$magicScopeVariable = $this->lock();
	// …
	return $text;
}

protected function lock() {
	if ( $this->mInParse ) {
		throw new LogicException( "Parser state cleared. […] Lock is held by: " . $this->mInParse );
	}
	$this->mInParse = ( new RuntimeException )->getTraceAsString();
	return new ScopedCallback( function () {
		$this->mInParse = false;
	} );
}

--- a/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@ -6506,12 +6506,13 @@ class Parser {
        // we can print the lock owner's backtrace for easier debugging
        $e = new RuntimeException;
        $this->mInParse = $e->getTraceAsString();
+       $caller = $e->getTrace()[6]['file'] . ':' . $e->getTrace()[6]['line'];
 
-       $recursiveCheck = new ScopedCallback( function () {
+       $recursiveCheck = new ScopedCallback( function () use ( $caller ) {
+       print "Parser::lock start for $caller\n";
            $this->mInParse = false;
        } );
    }

PHPUnit 9.6.21 by Sebastian Bergmann and contributors.

E                                                                   1 / 1 (100%)Parser::lock start for /mediawiki/tests/phpunit/includes/language/MessageTest.php:221


Time: 00:00.109, Memory: 51.00 MB

There was 1 error:

1) MessageTest::testWfMessageParams
LogicException: Parser state cleared while parsing. Did you call Parser::parse recursively? Lock is held by: #0 /mediawiki/includes/parser/Parser.php(933): MediaWiki\Parser\Parser->lock()
#1 /mediawiki/includes/parser/Parser.php(5022): MediaWiki\Parser\Parser->preprocess('{{PLURAL:$3|You...', Object(MediaWiki\Page\PageReferenceValue), Object(MediaWiki\Parser\ParserOptions))
#2 /mediawiki/includes/language/MessageParser.php(121): MediaWiki\Parser\Parser->transformMsg('{{PLURAL:$3|You...', Object(MediaWiki\Parser\ParserOptions), Object(MediaWiki\Page\PageReferenceValue))
#3 /mediawiki/includes/language/Message/Message.php(1479): MediaWiki\Language\MessageParser->transform('{{PLURAL:$3|You...', true, Object(LanguageEn), Object(MediaWiki\Page\PageReferenceValue))
#4 /mediawiki/includes/language/Message/Message.php(1059): MediaWiki\Message\Message->transformText('{{PLURAL:$3|You...')
#5 /mediawiki/includes/language/Message/Message.php(1107): MediaWiki\Message\Message->format('text')
#6 /mediawiki/tests/phpunit/includes/language/MessageTest.php(221): MediaWiki\Message\Message->text()
#7 …
#17 {main}

/mediawiki/includes/parser/Parser.php:6501
/mediawiki/includes/parser/Parser.php:933
/mediawiki/includes/parser/Parser.php:5022
/mediawiki/includes/language/MessageParser.php:121
/mediawiki/includes/language/Message/Message.php:1479
/mediawiki/includes/language/Message/Message.php:1059
/mediawiki/includes/language/Message/Message.php:1107
/mediawiki/tests/phpunit/includes/language/MessageTest.php:246

ERRORS!
Tests: 1, Assertions: 5, Errors: 1.
Parser::lock end for /mediawiki/tests/phpunit/includes/language/MessageTest.php:221