CMakeProjectManager: Make backup of CMake configuration before starting CMake

CMake's fileapi functionality will save the project structure in json
files in the .cmake/api/v1/reply directory.

When issuing a cmake command with -D variables CMake will update its
CMakeCache.txt file even if cmake will fail.

This commit will rename .cmake/api/v1/reply as .cmake/api/v1/reply.prev
and make a copy of CMakeCache.txt before starting CMake, and if
something fails, replace the existing files with the previous values.

Also make sure the changed values are not dissappearing when the
old .cmake/api/v1/reply gets parsed.

Fixes: QTCREATORBUG-24593
Change-Id: I82141786fea7068699e0f761a8978ba1f3203e47
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

1 files changed, 36 insertions, 1 deletions

diff --git a/src/plugins/cmakeprojectmanager/fileapireader.cpp b/src/plugins/cmakeprojectmanager/fileapireader.cpp
index 71fa5601a1..152f22b468 100644
--- a/src/plugins/cmakeprojectmanager/fileapireader.cpp
+++ b/src/plugins/cmakeprojectmanager/fileapireader.cpp
@@ -29,6 +29,8 @@
 #include "fileapiparser.h"
 #include "projecttreehelper.h"
 
+#include <coreplugin/messagemanager.h>
+
 #include <projectexplorer/projectexplorer.h>
 
 #include <utils/algorithm.h>
@@ -185,7 +187,8 @@ QList<CMakeBuildTarget> FileApiReader::takeBuildTargets(QString &errorMessage){
 
 CMakeConfig FileApiReader::takeParsedConfiguration(QString &errorMessage)
 {
-    Q_UNUSED(errorMessage)
+    if (m_lastCMakeExitCode != 0)
+        errorMessage = tr("CMake returned error code: %1").arg(m_lastCMakeExitCode);
 
     CMakeConfig cache = m_cache;
     m_cache.clear();
@@ -296,6 +299,34 @@ void FileApiReader::endState(const QFileInfo &replyFi)
     });
 }
 
+void FileApiReader::makeBackupConfiguration(bool store)
+{
+    FilePath reply = m_parameters.buildDirectory.pathAppended(".cmake/api/v1/reply");
+    FilePath replyPrev = m_parameters.buildDirectory.pathAppended(".cmake/api/v1/reply.prev");
+    if (!store)
+        std::swap(reply, replyPrev);
+
+    if (reply.exists()) {
+        if (replyPrev.exists())
+            FileUtils::removeRecursively(replyPrev);
+        QDir dir;
+        if (!dir.rename(reply.toString(), replyPrev.toString()))
+            Core::MessageManager::writeFlashing(tr("Failed to rename %1 to %2.")
+                                                .arg(reply.toString(), replyPrev.toString()));
+
+    }
+
+    FilePath cmakeCacheTxt = m_parameters.buildDirectory.pathAppended("CMakeCache.txt");
+    FilePath cmakeCacheTxtPrev = m_parameters.buildDirectory.pathAppended("CMakeCache.txt.prev");
+    if (!store)
+        std::swap(cmakeCacheTxt, cmakeCacheTxtPrev);
+
+    if (!FileUtils::copyIfDifferent(cmakeCacheTxt, cmakeCacheTxtPrev))
+        Core::MessageManager::writeFlashing(tr("Failed to copy %1 to %2.")
+                                            .arg(cmakeCacheTxt.toString(), cmakeCacheTxtPrev.toString()));
+
+}
+
 void FileApiReader::startCMakeState(const QStringList &configurationArguments)
 {
     qCDebug(cmakeFileApiMode) << "FileApiReader: START CMAKE STATE.";
@@ -306,6 +337,7 @@ void FileApiReader::startCMakeState(const QStringList &configurationArguments)
     connect(m_cmakeProcess.get(), &CMakeProcess::finished, this, &FileApiReader::cmakeFinishedState);
 
     qCDebug(cmakeFileApiMode) << ">>>>>> Running cmake with arguments:" << configurationArguments;
+    makeBackupConfiguration(true);
     m_cmakeProcess->run(m_parameters, configurationArguments);
 }
 
@@ -319,6 +351,9 @@ void FileApiReader::cmakeFinishedState(int code, QProcess::ExitStatus status)
     m_lastCMakeExitCode = m_cmakeProcess->lastExitCode();
     m_cmakeProcess.release()->deleteLater();
 
+    if (m_lastCMakeExitCode != 0)
+        makeBackupConfiguration(false);
+
     endState(FileApiParser::scanForCMakeReplyFile(m_parameters.workDirectory));
 }