Merge pull request #4180 from tybug/disable-hypothesis-events

Disable line coverage events where not used

Author: Zac-HD

hypothesis-python/RELEASE.rst

@@ -0,0 +1,3 @@
+RELEASE_TYPE: patch
+
+Hypothesis collects coverage information during the ``shrink`` and ``explain`` :ref:`phases <phases>` in order to show a more informative error message. On 3.12+, this uses :mod:`sys.monitoring`. This patch improves the performance of coverage collection on 3.12+ by disabling events we don't need.

hypothesis-python/src/hypothesis/internal/scrutineer.py

@@ -76,7 +76,6 @@ def trace(self, frame, event, arg):
             if event == "call":
                 return self.trace
             elif event == "line":
-                # manual inlining of self.trace_line for performance.
                 fname = frame.f_code.co_filename
                 if should_trace_file(fname):
                     current_location = (fname, frame.f_lineno)
@@ -87,10 +86,14 @@ def trace(self, frame, event, arg):
 
     def trace_line(self, code: types.CodeType, line_number: int) -> None:
         fname = code.co_filename
-        if should_trace_file(fname):
-            current_location = (fname, line_number)
-            self.branches.add((self._previous_location, current_location))
-            self._previous_location = current_location
+        if not should_trace_file(fname):
+            # this function is only called on 3.12+, but we want to avoid an
+            # assertion to that effect for performance.
+            return sys.monitoring.DISABLE  # type: ignore
+
+        current_location = (fname, line_number)
+        self.branches.add((self._previous_location, current_location))
+        self._previous_location = current_location
 
     def __enter__(self):
         if not self._should_trace: