ProcessLauncher: Don't emit error twice on process crash

Behave the same as QProcess in this circumstances.

Change-Id: If8175ccb7102d6a561584ee73c2e5c5844f2770d
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/tools/processlauncher/launchersockethandler.cpp

@@ -136,14 +136,18 @@ void LauncherSocketHandler::handleSocketClosed()
 void LauncherSocketHandler::handleProcessError()
 {
     Process * proc = senderProcess();
+
+    // In case of FailedToStart we won't receive finished signal, so we send the error
+    // packet and remove the process here and now. For all other errors we should expect
+    // corresponding finished signal to appear, so we will send the error data together with
+    // the finished packet later on.
+    if (proc->error() != QProcess::FailedToStart)
+        return;
+
     ProcessErrorPacket packet(proc->token());
     packet.error = proc->error();
     packet.errorString = proc->errorString();
     sendPacket(packet);
-
-    // In case of FailedToStart we won't receive finished signal, so we remove the process here.
-    // For all other errors we should expect corresponding finished signal to appear.
-    if (proc->error() == QProcess::FailedToStart)
     removeProcess(proc->token());
 }
 

tests/auto/utils/qtcprocess/tst_qtcprocess.cpp

@@ -201,6 +201,7 @@ private slots:
     void killBlockingProcess_data();
     void killBlockingProcess();
     void flushFinishedWhileWaitingForReadyRead();
+    void emitOneErrorOnCrash();
 
     void cleanupTestCase();
 
@@ -219,6 +220,7 @@ private:
     SUB_CREATOR_PROCESS(ProcessChannelForwarding);
     SUB_CREATOR_PROCESS(SubProcessChannelForwarding);
     SUB_CREATOR_PROCESS(KillBlockingProcess);
+    SUB_CREATOR_PROCESS(EmitOneErrorOnCrash);
 
     // In order to get a value associated with the certain subprocess use SubProcessClass::envVar().
     // The classes above define different custom executables. Inside initTestCase()
@@ -1312,6 +1314,29 @@ void tst_QtcProcess::flushFinishedWhileWaitingForReadyRead()
     QVERIFY(reply.contains(simpleTestData));
 }
 
+void tst_QtcProcess::EmitOneErrorOnCrash::main()
+{
+    abort();
+}
+
+void tst_QtcProcess::emitOneErrorOnCrash()
+{
+    SubCreatorConfig subConfig(EmitOneErrorOnCrash::envVar(), {});
+    TestProcess process;
+    subConfig.setupSubProcess(&process);
+
+    int errorCount = 0;
+    connect(&process, &QtcProcess::errorOccurred, this, [&errorCount] { ++errorCount; });
+    process.start();
+    QVERIFY(process.waitForStarted(1000));
+
+    QEventLoop loop;
+    connect(&process, &QtcProcess::finished, &loop, &QEventLoop::quit);
+    loop.exec();
+
+    QCOMPARE(errorCount, 1);
+}
+
 QTEST_MAIN(tst_QtcProcess)
 
 #include "tst_qtcprocess.moc"