Fixed an issue with silent hanging when a custom debug server is not found // Resolve #3756

HISTORY.rst

@@ -16,6 +16,7 @@ PlatformIO Core 5
   - Boosted `PlatformIO Debugging <https://docs.platformio.org/page/plus/debugging.html>`__  performance thanks to migrating the codebase to the pure Python 3 Asynchronous I/O stack
   - Support debugging on Windows using Windows CMD/CLI (`pio debug <https://docs.platformio.org/page/core/userguide/cmd_debug.html>`__) (`issue #3793 <https://github.com/platformio/platformio-core/issues/3793>`_)
   - Configure a custom pattern to determine when debugging server is started with a new `debug_server_ready_pattern <https://docs.platformio.org/page/projectconf/section_env_debug.html#debug-server-ready-pattern>`__ option
+  - Fixed an issue with silent hanging when a custom debug server is not found (`issue #3756 <https://github.com/platformio/platformio-core/issues/3756>`_)
 
 5.1.1 (2021-03-17)
 ~~~~~~~~~~~~~~~~~~

platformio/commands/debug.py

@@ -155,11 +155,13 @@ def cli(ctx, project_dir, project_conf, environment, verbose, interface, __unpro
     asyncio.set_event_loop(loop)
     client = GDBClientProcess(project_dir, debug_config)
     coro = client.run(__unprocessed)
-    loop.run_until_complete(coro)
+    try:
-    del client
+        loop.run_until_complete(coro)
-    if IS_WINDOWS:
+        if IS_WINDOWS:
-        # an issue with asyncio executor and STIDIN, it cannot be closed gracefully
+            # an issue with asyncio executor and STIDIN, it cannot be closed gracefully
-        proc.force_exit()
+            proc.force_exit()
-    loop.close()
+    finally:
+        del client
+        loop.close()
 
     return True

platformio/debug/process/server.py

@@ -51,10 +51,9 @@ class DebugServerProcess(DebugBaseProcess):
             server_executable = where_is_program(server_executable)
         if not os.path.isfile(server_executable):
             raise DebugInvalidOptionsError(
-                "\nCould not launch Debug Server '%s'. Please check that it "
+                "Could not launch Debug Server '%s'. Please check that it "
-                "is installed and is included in a system PATH\n\n"
+                "is installed and is included in a system PATH\n"
-                "See documentation:\n"
+                "See https://docs.platformio.org/page/plus/debugging.html"
-                "https://docs.platformio.org/page/plus/debugging.html\n"
                 % server_executable
             )