UI: Proper unsetenv is needed for Windows

source/carla_backend.py

@@ -1751,6 +1751,14 @@ class Host(object):
             keyvalue = "%s=%s" % (key, value)
             self.msvcrt._putenv(keyvalue.encode("utf-8"))
 
+    # extra
+    def unsetenv(self, key):
+        environ.pop(key)
+
+        if WINDOWS:
+            keyrm = "%s=" % key
+            self.msvcrt._putenv(keyrm.encode("utf-8"))
+
     def _init(self, libName):
         self.lib = cdll.LoadLibrary(libName)
 
@@ -2022,3 +2030,5 @@ class Host(object):
             self.msvcrt = cdll.msvcrt
             self.msvcrt._putenv.argtypes = [c_char_p]
             self.msvcrt._putenv.restype = None
+        else:
+            self.msvcrt = None

source/carla_database.py

@@ -1132,10 +1132,9 @@ class PluginRefreshW(QDialog):
         self.ui.group_options.setEnabled(False)
 
         if self.ui.ch_do_checks.isChecked():
-            if os.getenv("CARLA_DISCOVERY_NO_PROCESSING_CHECKS") is not None:
-                os.environ.pop("CARLA_DISCOVERY_NO_PROCESSING_CHECKS")
+            gCarla.host.unsetenv("CARLA_DISCOVERY_NO_PROCESSING_CHECKS")
         else:
-            os.environ["CARLA_DISCOVERY_NO_PROCESSING_CHECKS"] = "true"
+            gCarla.host.setenv("CARLA_DISCOVERY_NO_PROCESSING_CHECKS", "true")
 
         native, posix32, posix64, win32, win64 = (self.ui.ch_native.isChecked(),
                                                   self.ui.ch_posix32.isChecked(), self.ui.ch_posix64.isChecked(),

source/modules/native-plugins/resources/carla-plugin

@@ -62,6 +62,13 @@ class PluginHost(object):
 
         self.fPluginsInfo = []
 
+        if WINDOWS:
+            self.msvcrt = cdll.msvcrt
+            self.msvcrt._putenv.argtypes = [c_char_p]
+            self.msvcrt._putenv.restype = None
+        else:
+            self.msvcrt = None
+
     def _add(self, pluginId):
         if len(self.fPluginsInfo) != pluginId:
             return
@@ -513,6 +520,22 @@ class PluginHost(object):
     def get_host_osc_url_udp(self):
         return ""
 
+    # extra
+    def setenv(self, key, value):
+        environ[key] = value
+
+        if WINDOWS:
+            keyvalue = "%s=%s" % (key, value)
+            self.msvcrt._putenv(keyvalue.encode("utf-8"))
+
+    # extra
+    def unsetenv(self, key):
+        environ.pop(key)
+
+        if WINDOWS:
+            keyrm = "%s=" % key
+            self.msvcrt._putenv(keyrm.encode("utf-8"))
+
 # ------------------------------------------------------------------------------------------------------------
 # Main Window