From 23e67332a07774a5c94aea2f8770c139c50cd92b Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Wed, 29 Jan 2025 18:12:04 -0800
Subject: [PATCH] QProcess/Win: Properly report the reason of a fail-to-start

We were losing the GetLastError() by calling CloseHandle(),
QProcess::tr() or just not adding it.

Change-Id: Ic16faa6d68a32d42d620fffd1a8e72be718bf19d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
---
 src/corelib/io/qprocess_win.cpp                 | 15 ++++++++++++---
 tests/auto/corelib/io/qprocess/tst_qprocess.cpp | 16 ++++++++++++++--
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/corelib/io/qprocess_win.cpp b/src/corelib/io/qprocess_win.cpp
index 7d577a4ba49..1222322c16e 100644
--- a/src/corelib/io/qprocess_win.cpp
+++ b/src/corelib/io/qprocess_win.cpp
@@ -513,6 +513,12 @@ bool QProcessPrivate::callCreateProcess(QProcess::CreateProcessArguments *cpargs
                                  cpargs->inheritHandles, cpargs->flags, cpargs->environment,
                                  cpargs->currentDirectory, cpargs->startupInfo,
                                  cpargs->processInformation);
+    if (!success) {
+        // don't CloseHandle here (we'll do that in cleanup()) so GetLastError()
+        // remains unmodified
+        return false;
+    }
+
     if (stdinChannel.pipe[0] != INVALID_Q_PIPE) {
         CloseHandle(stdinChannel.pipe[0]);
         stdinChannel.pipe[0] = INVALID_Q_PIPE;
@@ -576,9 +582,10 @@ void QProcessPrivate::startProcess()
 
     if (!callCreateProcess(&cpargs)) {
         // Capture the error string before we do CloseHandle below
-        QString errorString = QProcess::tr("Process failed to start: %1").arg(qt_error_string());
+        QString errorString = qt_error_string();
         cleanup();
-        setErrorAndEmit(QProcess::FailedToStart, errorString);
+        setErrorAndEmit(QProcess::FailedToStart,
+                        QProcess::tr("Process failed to start: %1").arg(errorString));
         return;
     }
 
@@ -946,7 +953,9 @@ bool QProcessPrivate::startDetached(qint64 *pid)
     if (!success) {
         if (pid)
             *pid = -1;
-        setErrorAndEmit(QProcess::FailedToStart);
+        QString errorString = qt_error_string();
+        setErrorAndEmit(QProcess::FailedToStart,
+                        QProcess::tr("Process failed to start: %1").arg(errorString));
     }
 
     closeChannels();
diff --git a/tests/auto/corelib/io/qprocess/tst_qprocess.cpp b/tests/auto/corelib/io/qprocess/tst_qprocess.cpp
index 5352c625146..8a36c9929a3 100644
--- a/tests/auto/corelib/io/qprocess/tst_qprocess.cpp
+++ b/tests/auto/corelib/io/qprocess/tst_qprocess.cpp
@@ -25,6 +25,9 @@
 #  include <sys/resource.h>
 #  include <sys/wait.h>
 #endif
+#ifdef Q_OS_WIN
+#  include <winerror.h>
+#endif
 
 #include <QtTest/private/qemulationdetector_p.h>
 
@@ -424,8 +427,13 @@ void tst_QProcess::simpleStartFail()
 
 #ifdef Q_OS_UNIX
     QVERIFY2(process.errorString().contains(": execve: "), process.errorString().toLocal8Bit());
-    QVERIFY2(process.errorString().contains(qt_error_string(ENOENT)), process.errorString().toLocal8Bit());
+    int errorcode = ENOENT;
+#else
+    // value happens to match ENOENT, but that's a coincidence
+    int errorcode = ERROR_FILE_NOT_FOUND;
 #endif
+    QVERIFY2(process.errorString().contains(qt_error_string(errorcode)),
+             process.errorString().toLocal8Bit());
 }
 
 void tst_QProcess::readFromProcess()
@@ -2940,8 +2948,12 @@ void tst_QProcess::setNonExistentWorkingDirectory()
 
 #ifdef Q_OS_UNIX
     QVERIFY2(process.errorString().contains(": chdir: "), process.errorString().toLocal8Bit());
-    QVERIFY2(process.errorString().contains(qt_error_string(ENOENT)), process.errorString().toLocal8Bit());
+    int errorcode = ENOENT;
+#else
+    int errorcode = ERROR_DIRECTORY;
 #endif
+    QVERIFY2(process.errorString().contains(qt_error_string(errorcode)),
+             process.errorString().toLocal8Bit());
 }
 
 void tst_QProcess::startFinishStartFinish()