fix: runpy.run_path(path) crashes with pathlib.Path

CHANGES.rst

@@ -23,7 +23,11 @@ upgrading your version of coverage.py.
 Unreleased
 ----------
 
-Nothing yet.
+- Fix: coverage used to fail when measuring code using :func:`runpy.run_path
+  <python:runpy.run_path>` with a :class:`Path <python:pathlib.Path>` argument.
+  This is now fixed, thanks to `Ask Hjorth Larsen <pull 1819_>`_.
+
+.. _pull 1819: https://github.com/nedbat/coveragepy/pull/1819/files
 
 
 .. scriv-start-here

CONTRIBUTORS.txt

@@ -25,6 +25,7 @@ Artem Dayneko
 Arthur Deygin
 Arthur Rio
 Asher Foa
+Ask Hjorth Larsen
 Ben Carlsson
 Ben Finney
 Benjamin Parzella

coverage/inorout.py

@@ -321,7 +321,8 @@ def nope(disp: TFileDisposition, reason: str) -> TFileDisposition:
             # co_filename value.
             dunder_file = frame.f_globals and frame.f_globals.get("__file__")
             if dunder_file:
-                filename = source_for_file(dunder_file)
+                # Danger: __file__ can (rarely?) be of type Path.
+                filename = source_for_file(str(dunder_file))
                 if original_filename and not original_filename.startswith("<"):
                     orig = os.path.basename(original_filename)
                     if orig != os.path.basename(filename):

tests/test_python.py

@@ -63,3 +63,24 @@ def test_source_for_file_windows(tmp_path: pathlib.Path) -> None:
     # If both pyw and py exist, py is preferred
     a_py.write_text("")
     assert source_for_file(src + 'c') == src
+
+
+class RunpyTest(CoverageTest):
+    """Tests using runpy."""
+
+    @pytest.mark.parametrize("convert_to", ["str", "Path"])
+    def test_runpy_path(self, convert_to: str) -> None:
+        # Ensure runpy.run_path(path) works when path is pathlib.Path or str.
+        #
+        # runpy.run_path(pathlib.Path(...)) causes __file__ to be a Path,
+        # which may make source_for_file() stumble (#1819) with:
+        #
+        #    AttributeError: 'PosixPath' object has no attribute 'endswith'
+
+        self.check_coverage(f"""\
+            import runpy
+            from pathlib import Path
+            pyfile = Path('script.py')
+            pyfile.write_text('')
+            runpy.run_path({convert_to}(pyfile))
+        """)