Do not overwrite detailed error message if process fails to launch

On Unix we get a detailed error message when a process fails to start,
but later on we overwrite it with a generic "Process fails to start".
Fix this by keeping the original error message (if one is available).

This fixes a regression introduced in commit 5147f73ac3.

Task-number: QTBUG-49286
Change-Id: Idd0f0fed9773d39f2947fc3e532b51e670952caf
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/corelib/io/qprocess.cpp b/src/corelib/io/qprocess.cpp
index 8fbe96adb9..b09c99985c 100644
--- a/src/corelib/io/qprocess.cpp
+++ b/src/corelib/io/qprocess.cpp
@@ -1179,14 +1179,15 @@ bool QProcessPrivate::_q_startupNotification()
 
     if (startupSocketNotifier)
         startupSocketNotifier->setEnabled(false);
-    if (processStarted()) {
+    QString errorMessage;
+    if (processStarted(&errorMessage)) {
         q->setProcessState(QProcess::Running);
         emit q->started(QProcess::QPrivateSignal());
         return true;
     }
 
     q->setProcessState(QProcess::NotRunning);
-    setErrorAndEmit(QProcess::FailedToStart);
+    setErrorAndEmit(QProcess::FailedToStart, errorMessage);
 #ifdef Q_OS_UNIX
     // make sure the process manager removes this entry
     waitForDeadChild();