CMake: Fall back to reading CMakeCache.txt

Allows the user to select cache settings even if configuring failed.

Change-Id: I821c28f386e0c249b4c4d9c6561a377cb48b3f2d
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/cmakeprojectmanager/fileapiparser.cpp

@@ -838,6 +838,7 @@ static QStringList uniqueTargetFiles(const Configuration &config)
 
 FileApiData FileApiParser::parseData(QPromise<std::shared_ptr<FileApiQtcData>> &promise,
                                      const FilePath &replyFilePath,
+                                     const Utils::FilePath &buildDir,
                                      const QString &cmakeBuildType,
                                      QString &errorMessage)
 {
@@ -857,7 +858,11 @@ FileApiData FileApiParser::parseData(QPromise<std::shared_ptr<FileApiQtcData>> &
     result.replyFile = readReplyFile(replyFilePath, errorMessage);
     if (cancelCheck())
         return {};
-    result.cache = readCacheFile(result.replyFile.jsonFile("cache", replyDir), errorMessage);
+    const FilePath cachePathFromReply = result.replyFile.jsonFile("cache", replyDir);
+    if (cachePathFromReply.isEmpty())
+        result.cache = CMakeConfig::fromFile(buildDir / "CMakeCache.txt", &errorMessage);
+    else
+        result.cache = readCacheFile(cachePathFromReply, errorMessage);
     if (cancelCheck())
         return {};
     result.cmakeFiles = readCMakeFilesFile(result.replyFile.jsonFile("cmakeFiles", replyDir),

src/plugins/cmakeprojectmanager/fileapiparser.h

@@ -223,6 +223,7 @@ class FileApiParser
 public:
     static FileApiData parseData(QPromise<std::shared_ptr<FileApiQtcData>> &promise,
                                  const Utils::FilePath &replyFilePath,
+                                 const Utils::FilePath &buildDir,
                                  const QString &cmakeBuildType,
                                  QString &errorMessage);
 

src/plugins/cmakeprojectmanager/fileapireader.cpp

@@ -263,6 +263,7 @@ void FileApiReader::endState(const FilePath &replyFilePath, bool restoredFromBac
                             auto result = std::make_shared<FileApiQtcData>();
                             FileApiData data = FileApiParser::parseData(promise,
                                                                         replyFilePath,
+                                                                        buildDirectory,
                                                                         cmakeBuildType,
                                                                         result->errorMessage);
                             if (result->errorMessage.isEmpty()) {
@@ -270,6 +271,7 @@ void FileApiReader::endState(const FilePath &replyFilePath, bool restoredFromBac
                                                       sourceDirectory, buildDirectory);
                             } else {
                                 qWarning() << result->errorMessage;
+                                result->cache = std::move(data.cache);
                             }
 
                             promise.addResult(result);