fix: stale frappe.local (backport frappe#20695) (frappe#20700)

* fix: stale `frappe.local` (frappe#20695)

* fix: stale `frappe.local`

Co-Authored-By: Aditya Hase <aditya@adityahase.com>

* fix: force re-init in request

To ensure that any one bad request can not completely cause recurring
loop of broken requests due to bad locals, we just force-init locals on
every request.

---------

Co-authored-by: Aditya Hase <aditya@adityahase.com>
(cherry picked from commit 1e9ede4)

# Conflicts:
#	frappe/__init__.py
#	frappe/app.py

* chore: conflicts

---------

Co-authored-by: Ankush Menat <ankush@frappe.io>

frappe/__init__.py

@@ -179,9 +179,9 @@ def set_user_lang(user, user_language=None):
 # end: static analysis hack
 
 
-def init(site, sites_path=None, new_site=False):
+def init(site, sites_path=".", new_site=False, force=False):
 	"""Initialize frappe for the current site. Reset thread locals `frappe.local`"""
-	if getattr(local, "initialised", None):
+	if getattr(local, "initialised", None) and not force:
 		return
 
 	if not sites_path:

frappe/app.py

@@ -90,12 +90,18 @@ def application(request):
 		rollback = after_request(rollback)
 
 	finally:
+		# Important note:
+		# this function *must* always return a response, hence any exception thrown outside of
+		# try..catch block like this finally block needs to be handled appropriately.
+
 		if request.method in ("POST", "PUT") and frappe.db and rollback:
 			frappe.db.rollback()
 
-		if getattr(frappe.local, "initialised", False):
-			for after_request_task in frappe.get_hooks("after_request"):
-				frappe.call(after_request_task, response=response, request=request)
+		try:
+			run_after_request_hooks(request, response)
+		except Exception as e:
+			# We can not handle exceptions safely here.
+			frappe.logger().error("Failed to run after request hook", exc_info=True)
 
 		log_request(request, response)
 		process_response(response)
@@ -104,12 +110,20 @@ def application(request):
 	return response
 
 
+def run_after_request_hooks(request, response):
+	if not getattr(frappe.local, "initialised", False):
+		return
+
+	for after_request_task in frappe.get_hooks("after_request"):
+		frappe.call(after_request_task, response=response, request=request)
+
+
 def init_request(request):
 	frappe.local.request = request
 	frappe.local.is_ajax = frappe.get_request_header("X-Requested-With") == "XMLHttpRequest"
 
 	site = _site or request.headers.get("X-Frappe-Site-Name") or get_site_name(request.host)
-	frappe.init(site=site, sites_path=_sites_path)
+	frappe.init(site=site, sites_path=_sites_path, force=True)
 
 	if not (frappe.local.conf and frappe.local.conf.db_name):
 		# site does not exist