Revert "[Python dev ctrl] ChipStack is initialized twice on Darwin (#… (

#6550)

* Revert "[Python dev ctrl] ChipStack is initialized twice on Darwin (#6066)"

This reverts commit 23cba58.

Logic seemed correct before: python only works on device layer and
device layer requires initialization.

Unsure why darwin is initialized twice, howver the native bit is NOT
supposed to be called by the device-ctrl-code only by chip-native. Have
to figure out how not to break chip-native.

* Track platform manager initialization and do not allow double-init

* Added large comment about thread safety in the double-init check of the platform manager

* Removed std::atomic reference as it is not relevant here: we need a mutex to wait for init to complete, not just blindly say iniialized before it is done

src/controller/python/chip/native/StackInit.cpp

@@ -72,13 +72,11 @@ void pychip_native_init()
     }
 #endif // CHIP_DEVICE_LAYER_TARGET_LINUX && CHIP_DEVICE_CONFIG_ENABLE_CHIPOBLE
 
-#ifndef CONFIG_DEVICE_LAYER
     err = chip::DeviceLayer::PlatformMgr().InitChipStack();
     if (err != CHIP_NO_ERROR)
     {
         ChipLogError(DeviceLayer, "Failed to initialize CHIP stack: platform init failed: %s", chip::ErrorStr(err));
     }
-#endif
     int result   = pthread_create(&sPlatformMainThread, nullptr, PlatformMainLoop, nullptr);
     int tmpErrno = errno;
 

src/include/platform/PlatformManager.h

@@ -95,6 +95,7 @@ class PlatformManager
     CHIP_ERROR Shutdown();
 
 private:
+    bool mInitialized = false;
     // ===== Members for internal use by the following friends.
 
     friend class PlatformManagerImpl;
@@ -181,7 +182,21 @@ namespace DeviceLayer {
 
 inline CHIP_ERROR PlatformManager::InitChipStack()
 {
-    return static_cast<ImplClass *>(this)->_InitChipStack();
+    // NOTE: this is NOT thread safe and cannot be as the chip stack lock is prepared by
+    // InitChipStack itself on many platforms.
+    //
+    // In the future, this could be moved into specific platform code (where it can
+    // be made thread safe). In general however, init twice
+    // is likely a logic error and we may want to avoid that path anyway. Likely to
+    // be done once code stabilizes a bit more.
+    if (mInitialized)
+    {
+        return CHIP_NO_ERROR;
+    }
+
+    CHIP_ERROR err = static_cast<ImplClass *>(this)->_InitChipStack();
+    mInitialized   = (err == CHIP_NO_ERROR);
+    return err;
 }
 
 inline CHIP_ERROR PlatformManager::AddEventHandler(EventHandlerFunct handler, intptr_t arg)