testlib: Prevent Apple test logger from stomping on other loggers

We were potentially adding the Apple test logger multiple times, and we
didn't consider whether the existing loggers were logging to file or not
when circumventing them.

We now don't use the Apple logger if it would touch stderr and some other
logger is using stdout. In the case of no explicit logger being specified
on the command line, we allow the Apple logger to take priority over the
default plain test logger.

Change-Id: I31bbec4f4b3ab84ba9a2be35e8e5db08fee071a7
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/corelib/kernel/qcore_mac_p.h b/src/corelib/kernel/qcore_mac_p.h
index acb87f8a3c..f96e7358a2 100644
--- a/src/corelib/kernel/qcore_mac_p.h
+++ b/src/corelib/kernel/qcore_mac_p.h
@@ -202,6 +202,7 @@ class Q_CORE_EXPORT AppleUnifiedLogger
 public:
     static bool messageHandler(QtMsgType msgType, const QMessageLogContext &context, const QString &message,
         const QString &subsystem = QString());
+    static bool willMirrorToStderr();
 private:
     static os_log_type_t logTypeForMessageType(QtMsgType msgType);
     static os_log_t cachedLog(const QString &subsystem, const QString &category);