composer serve: create and set log directory

Why:

- New users will appreciate having easy access to MediaWiki logs; in
  order to make that easier, we need to have a directory to write to and
  set an environment variable to use that directory

What:

- Set MW_LOG_DIR for the `serve` command
- Add a `logs` directory at the root of MW, and gitignore it
- Create the `logs` directory via DevelopmentSettings, if MW_LOG_DIR is
  defined but does not exist

I considered the `cache` directory for the log location as it
already exists, but it seemed preferable to not conflate cache and
logs.

Bug: T347347
Change-Id: Ic3ddb0203df07a0c93df9f431b25a2a5d9ecc407

1 files changed, 3 insertions, 0 deletions

diff --git a/includes/DevelopmentSettings.php b/includes/DevelopmentSettings.php
index d8346b4e499d..fd4e4b94b8f9 100644
--- a/includes/DevelopmentSettings.php
+++ b/includes/DevelopmentSettings.php
@@ -55,6 +55,9 @@ $wgShowHostnames = true;
 // Enable log files
 $logDir = getenv( 'MW_LOG_DIR' );
 if ( $logDir ) {
+	if ( !file_exists( $logDir ) ) {
+		mkdir( $logDir );
+	}
 	if ( MW_ENTRY_POINT === 'cli' ) {
 		$wgDebugLogFile = "$logDir/mw-debug-cli.log";
 	} else {