chore(flask): avoid using deprecated internals (#4433)

The following flask attributes have been deprecated in flask v2.2.2 and will be removed in the next minor release:

    flask. _app_ctx_stack
    flask. _request_ctx_stack

This change replaces deprecated methods with flask globals (flask.current_app and flask.request).

Author: mabdinur

ddtrace/contrib/flask/helpers.py

@@ -8,9 +8,11 @@
 
 def get_current_app():
     """Helper to get the flask.app.Flask from the current app context"""
-    appctx = flask._app_ctx_stack.top
-    if appctx:
-        return appctx.app
+    try:
+        return flask.current_app
+    except RuntimeError:
+        # raised if current_app is None: https://github.com/pallets/flask/blob/2.1.3/src/flask/globals.py#L40
+        pass
     return None
 
 

ddtrace/contrib/flask/patch.py

@@ -587,7 +587,9 @@ def traced_jsonify(wrapped, instance, args, kwargs):
 
 def _set_request_tags(span):
     try:
-        request = flask._request_ctx_stack.top.request
+        # raises RuntimeError if a request is not active:
+        # https://github.com/pallets/flask/blob/2.1.3/src/flask/globals.py#L40
+        request = flask.request
 
         # DEV: This name will include the blueprint name as well (e.g. `bp.index`)
         if not span.get_tag(FLASK_ENDPOINT) and request.endpoint:

releasenotes/notes/remove-deprecated-flask-methods-8d7a4a3d32c3c69d.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    flask: add support for flask v2.3. Remove deprecated usages of ``flask._app_ctx_stack`` and ``flask._request_ctx_stack``.