Fix QbsProcess::cancel()

Do proper state checking. In particular, only send a stop packet to the
launcher if we are in the running state.
This fixes a potential null pointer access when doing dry run builds.

Change-Id: Ib3efdd09c4094190c746464718d642b353ae7566
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 13 insertions, 1 deletions

diff --git a/src/lib/corelib/tools/qbsprocess.cpp b/src/lib/corelib/tools/qbsprocess.cpp
index 8495d72a0..52ce3f25a 100644
--- a/src/lib/corelib/tools/qbsprocess.cpp
+++ b/src/lib/corelib/tools/qbsprocess.cpp
@@ -88,7 +88,19 @@ void QbsProcess::doStart()
 
 void QbsProcess::cancel()
 {
-    sendPacket(StopProcessPacket(token()));
+    switch (m_state) {
+    case QProcess::NotRunning:
+        break;
+    case QProcess::Starting:
+        m_errorString = Tr::tr("Process canceled before it was started.");
+        m_error = QProcess::FailedToStart;
+        m_state = QProcess::NotRunning;
+        emit error(m_error);
+        break;
+    case QProcess::Running:
+        sendPacket(StopProcessPacket(token()));
+        break;
+    }
 }
 
 QByteArray QbsProcess::readAllStandardOutput()