Don't call the view yourself (and return a result) from process_view

calling the view yourself short-circuits the correct handling, which is not
what we want. It's not abundantly clear from the docs that this is generally
not what we want, but it is cimplied:

> It should return either None or an HttpResponse object. If it returns None,
> Django will continue processing this request, executing any other
> process_view() middleware and, then, the appropriate view. If it returns an
> HttpResponse object, Django won’t bother calling the appropriate view; it’ll
> apply response middleware to that HttpResponse and return the result.

We don't want to do any short-circuiting here, we just want to measure time
and have a view_name to display. Moving stuff around fixes it.

(That this was an error became clear when I wanted to do process_exception
in another Middleware, and that was never called)

bugsink/middleware.py

@@ -33,22 +33,19 @@ class PerformanceStatsMiddleware:
     """TSTTCPW to get some handle on view-performance (mostly for UI views). The direct cause for introducing this is
     that I got sent on a wild goose chase by the Django Debug Toolbar, which reported long (>100ms) CPU times for some
     view when it was the DJDT itself that was causing most of that time.
-
-    Yes this only measures the time spent in the view function itself and not the time in the surrounding Middleware,
-    but the whole point is to measure where individual views might be slow.
     """
 
     def __init__(self, get_response):
         self.get_response = get_response
+        self.view_name = "<<unknown>>"
 
     def __call__(self, request):
-        return self.get_response(request)
+        t0 = time()
+        result = self.get_response(request)
+        took = (time() - t0) * 1000
+        performance_logger.info(f"{took:6.2f}ms / {len(connection.queries)} queries: '{ self.view_name }'")
+        return result
 
     def process_view(self, request, view_func, view_args, view_kwargs):
-        t0 = time()
-        result = view_func(request, *view_args, **view_kwargs)
-        took = (time() - t0) * 1000
-        if not request.path.startswith("/static"):
-            performance_logger.info(f"{took:6.2f}ms / {len(connection.queries)} queries: '{ view_func.__name__ }'")
-
-        return result
+        self.view_name = view_func.__name__
+        return None