exception: Remove 'exception-json' logging channel

It provided structured exception data in a custom machine-readable
format. Since MediaWiki 1.26, structured exception data conforming to
the PSR-3 logging standard is also available on the 'exception' log
channel, and nobody uses 'exception-json' anymore. But the fact that
it exists and logs errors by default means that it has to be disabled,
and clutters configs, for example:
https://gerrit.wikimedia.org/g/operations/mediawiki-config/+/c0e5c7f71d70de5749f6770abcbbb7e57032bd29/wmf-config/InitialiseSettings.php#2225
https://gerrit.wikimedia.org/g/mediawiki/vagrant/+/c96e609b6ff6a73a412d3fd0a4291259eee026f6/puppet/modules/role/templates/psr3/settings.php.erb#57

Historical context:
* Iacda90fb401f6a45ed1ac1a991e088: Add "exception-json" channel, 2013.
* Ia7ba355d5925a6268ffa321ffc13cc: Add "error-json" channel, 2015.
* I71499d895582bdea033a2516c902e2: Convert "exception" to PSR-3, 2015.
* I782c96dac1181d12267fa610345e87: WMF disables "exception-json", 2017.
* I7a6e6fa52a47a29ec04411a6c8b05e: Remove "error-json" channel, 2024.

The custom data format has been reused for formatting exceptions in
the REST API, so keep getStructuredExceptionData() and rescue the tests.

Bug: T193472
Change-Id: If730618e5371a467cb76db239916b6bbe42512e3

2 files changed, 12 insertions, 38 deletions

diff --git a/tests/phpunit/includes/exception/MWExceptionTest.php b/tests/phpunit/includes/exception/MWExceptionTest.php
index 5c3564479dd7..8e4bd94e8a5e 100644
--- a/tests/phpunit/includes/exception/MWExceptionTest.php
+++ b/tests/phpunit/includes/exception/MWExceptionTest.php
@@ -24,26 +24,6 @@ class MWExceptionTest extends MediaWikiIntegrationTestCase {
 	}
 
 	/**
-	 * Verify the exception classes are JSON serializabe.
-	 *
-	 * @dataProvider provideExceptionClasses
-	 */
-	public function testJsonSerializeExceptions( $exception_class ) {
-		$json = MWExceptionHandler::jsonSerializeException(
-			new $exception_class()
-		);
-		$this->assertIsString( $json,
-			"The $exception_class exception should be JSON serializable, got false." );
-	}
-
-	public static function provideExceptionClasses() {
-		return [
-			[ Exception::class ],
-			[ MWException::class ],
-		];
-	}
-
-	/**
 	 * @covers \MWException::report
 	 */
 	public function testReport() {
diff --git a/tests/phpunit/unit/includes/exception/MWExceptionHandlerTest.php b/tests/phpunit/unit/includes/exception/MWExceptionHandlerTest.php
index 8fb9dfc07b60..d5f57451fa61 100644
--- a/tests/phpunit/unit/includes/exception/MWExceptionHandlerTest.php
+++ b/tests/phpunit/unit/includes/exception/MWExceptionHandlerTest.php
@@ -133,23 +133,21 @@ TEXT;
 	}
 
 	/**
-	 * @dataProvider provideJsonSerializedKeys
+	 * @dataProvider provideGetStructuredExceptionDataKeys
 	 * @param string $expectedKeyType Type expected as returned by get_debug_type()
 	 * @param string $exClass An exception class (ie: Exception, MWException)
 	 * @param string $key Name of the key to validate in the serialized JSON
 	 */
-	public function testJsonserializeexceptionKeys( $expectedKeyType, $exClass, $key ) {
-		$json = json_decode(
-			MWExceptionHandler::jsonSerializeException( new $exClass() )
-		);
-		$this->assertObjectHasProperty( $key, $json );
-		$this->assertSame( $expectedKeyType, get_debug_type( $json->$key ), "Type of the '$key' key" );
+	public function testGetStructuredExceptionDataKeys( $expectedKeyType, $exClass, $key ) {
+		$data = MWExceptionHandler::getStructuredExceptionData( new $exClass() );
+		$this->assertArrayHasKey( $key, $data );
+		$this->assertSame( $expectedKeyType, get_debug_type( $data[$key] ), "Type of the '$key' key" );
 	}
 
 	/**
 	 * Each case provides: [ type, exception class, key name ]
 	 */
-	public static function provideJsonSerializedKeys() {
+	public static function provideGetStructuredExceptionDataKeys() {
 		foreach ( [ Exception::class, MWException::class ] as $exClass ) {
 			yield [ 'string', $exClass, 'id' ];
 			yield [ 'string', $exClass, 'file' ];
@@ -165,26 +163,22 @@ TEXT;
 	 * Given wgLogExceptionBacktrace is true
 	 * then serialized exception must have a backtrace
 	 */
-	public function testJsonserializeexceptionBacktracingEnabled() {
+	public function testGetStructuredExceptionDataBacktracingEnabled() {
 		TestingAccessWrapper::newFromClass( MWExceptionHandler::class )
 			->logExceptionBacktrace = true;
-		$json = json_decode(
-			MWExceptionHandler::jsonSerializeException( new Exception() )
-		);
-		$this->assertObjectHasProperty( 'backtrace', $json );
+		$data = MWExceptionHandler::getStructuredExceptionData( new Exception() );
+		$this->assertArrayHasKey( 'backtrace', $data );
 	}
 
 	/**
 	 * Given wgLogExceptionBacktrace is false
 	 * then serialized exception must not have a backtrace
 	 */
-	public function testJsonserializeexceptionBacktracingDisabled() {
+	public function testGetStructuredExceptionDataBacktracingDisabled() {
 		TestingAccessWrapper::newFromClass( MWExceptionHandler::class )
 			->logExceptionBacktrace = false;
-		$json = json_decode(
-			MWExceptionHandler::jsonSerializeException( new Exception() )
-		);
-		$this->assertObjectNotHasProperty( 'backtrace', $json );
+		$data = MWExceptionHandler::getStructuredExceptionData( new Exception() );
+		$this->assertArrayNotHasKey( 'backtrace', $data );
 	}
 
 	/**