[App] Hot fix: Resolve detection of python debugger (#16068)

Co-authored-by: thomas <[email protected]>
Co-authored-by: Carlos Mocholí <[email protected]>

(cherry picked from commit eae56ee)

Author: tchaton

src/lightning_app/CHANGELOG.md

@@ -23,6 +23,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Fixed `AutoScaler` raising an exception when non-default cloud compute is specified ([#15991](https://github.com/Lightning-AI/lightning/pull/15991))
 - Fixed and improvements of login flow ([#16052](https://github.com/Lightning-AI/lightning/pull/16052))
 
+- Fixed the debugger detection mechanism for lightning App in VSCode ([#16068](https://github.com/Lightning-AI/lightning/pull/16068))
+
 
 ## [1.8.4] - 2022-12-08
 

src/lightning_app/utilities/app_helpers.py

@@ -511,12 +511,33 @@ def is_static_method(klass_or_instance, attr) -> bool:
     return isinstance(inspect.getattr_static(klass_or_instance, attr), staticmethod)
 
 
+def _lightning_dispatched() -> bool:
+    return bool(int(os.getenv("LIGHTNING_DISPATCHED", 0)))
+
+
+def _using_debugger() -> bool:
+    """This method is used to detect whether the app is run with a debugger attached."""
+    if "LIGHTNING_DETECTED_DEBUGGER" in os.environ:
+        return True
+
+    # Collect the information about the process.
+    parent_process = os.popen(f"ps -ax | grep -i {os.getpid()} | grep -v grep").read()
+
+    # Detect whether VSCode or PyCharm debugger are used
+    use_debugger = "debugpy" in parent_process or "pydev" in parent_process
+
+    # Store the result to avoid multiple popen calls.
+    if use_debugger:
+        os.environ["LIGHTNING_DETECTED_DEBUGGER"] = "1"
+    return use_debugger
+
+
 def _should_dispatch_app() -> bool:
     return (
-        __debug__
-        and "_pytest.doctest" not in sys.modules
-        and not bool(int(os.getenv("LIGHTNING_DISPATCHED", "0")))
+        not _lightning_dispatched()
         and "LIGHTNING_APP_STATE_URL" not in os.environ
+        # Keep last to avoid running it if already dispatched
+        and _using_debugger()
     )