consistently handle empty program string in QProcess::start overloads

All overloads of QProcess::start will now check whether the program
string is empty and in that case
  - set error to FailedToStart,
  - set errorString to "No program defined",
  - emit error.

Until now only one of the three overloads behaved like this.

As a side effect, start(QString(), QStringList()) will not crash on
Windows anymore.

Task-number: QTBUG-47404
Change-Id: I2f93657204fe3643b1d74a74817843c05fc4a96b
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/corelib/io/qprocess.cpp b/src/corelib/io/qprocess.cpp
index 1842541644..914774b433 100644
--- a/src/corelib/io/qprocess.cpp
+++ b/src/corelib/io/qprocess.cpp
@@ -2062,6 +2062,13 @@ void QProcess::start(const QString &program, const QStringList &arguments, OpenM
         qWarning("QProcess::start: Process is already running");
         return;
     }
+    if (program.isEmpty()) {
+        Q_D(QProcess);
+        d->processError = QProcess::FailedToStart;
+        setErrorString(tr("No program defined"));
+        emit error(d->processError);
+        return;
+    }
 
     d->program = program;
     d->arguments = arguments;
@@ -2086,7 +2093,10 @@ void QProcess::start(OpenMode mode)
         return;
     }
     if (d->program.isEmpty()) {
-        qWarning("QProcess::start: program not set");
+        Q_D(QProcess);
+        d->processError = QProcess::FailedToStart;
+        setErrorString(tr("No program defined"));
+        emit error(d->processError);
         return;
     }