Fix assertion on empty project path; Change cwd of plugin bridges

Signed-off-by: falkTX <falktx@falktx.com>

source/backend/engine/CarlaEngine.cpp

@@ -1406,7 +1406,8 @@ bool CarlaEngine::saveProject(const char* const filename, const bool setAsCurren
 #ifndef BUILD_BRIDGE_ALTERNATIVE_ARCH
 const char* CarlaEngine::getCurrentProjectFolder() const noexcept
 {
-    return pData->currentProjectFolder;
+    return pData->currentProjectFolder.isNotEmpty() ? pData->currentProjectFolder.buffer()
+                                                    : nullptr;
 }
 
 const char* CarlaEngine::getCurrentProjectFilename() const noexcept

source/backend/plugin/CarlaPluginBridge.cpp

@@ -320,7 +320,19 @@ protected:
             carla_stdout("Starting plugin bridge, command is:\n%s \"%s\" \"%s\" \"%s\" " P_INT64,
                          fBridgeBinary.toRawUTF8(), getPluginTypeAsString(kPlugin->getType()), filename.toRawUTF8(), fLabel.toRawUTF8(), kPlugin->getUniqueId());
 
-            started = fProcess->start(arguments);
+            const File projFolder(kEngine->getCurrentProjectFolder());
+
+            if (projFolder.isNotNull())
+            {
+                const File oldFolder(File::getCurrentWorkingDirectory());
+                projFolder.setAsCurrentWorkingDirectory();
+                started = fProcess->start(arguments);
+                oldFolder.setAsCurrentWorkingDirectory();
+            }
+            else
+            {
+                started = fProcess->start(arguments);
+            }
         }
 
         if (! started)

source/modules/water/files/File.cpp

@@ -1109,6 +1109,11 @@ File File::getCurrentWorkingDirectory()
     return File (String (dest));
 }
 
+bool File::setAsCurrentWorkingDirectory() const
+{
+    return SetCurrentDirectory (getFullPathName().toWideCharPointer()) != FALSE;
+}
+
 bool File::isSymbolicLink() const
 {
     return (GetFileAttributes (fullPath.toUTF8()) & FILE_ATTRIBUTE_REPARSE_POINT) != 0;
@@ -1342,6 +1347,11 @@ File File::getCurrentWorkingDirectory()
     return File (CharPointer_UTF8 (cwd));
 }
 
+bool File::setAsCurrentWorkingDirectory() const
+{
+    return chdir (getFullPathName().toUTF8()) == 0;
+}
+
 File water_getExecutableFile();
 File water_getExecutableFile()
 {