fix: make third-party detection work with namespace packages. #1231

3 files changed, 113 insertions, 12 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 7e5f7782..696dd4b0 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -22,10 +22,17 @@ This list is detailed and covers changes in each pre-release version.
 Unreleased
 ----------
 
+- Namespace packages being measured weren't properly handled by the new code
+  that ignores third-party packages. If the namespace package was installed, it
+  was ignored as a third-party package.  That problem (`issue 1231`_) is now
+  fixed.
+
 - The :meth:`.CoverageData.contexts_by_lineno` method was documented to return
   a dict, but was returning a defaultdict.  Now it returns a plain dict.  It
   also no longer returns negative numbered keys.
 
+.. _issue 1231: https://github.com/nedbat/coveragepy/issues/1231
+
 
 .. _changes_601:
 
diff --git a/coverage/inorout.py b/coverage/inorout.py
index 496ced35..c90e3d59 100644
--- a/coverage/inorout.py
+++ b/coverage/inorout.py
@@ -107,17 +107,26 @@ def module_has_file(mod):
     return os.path.exists(mod__file__)
 
 
-def file_for_module(modulename):
-    """Find the file for `modulename`, or return None."""
+def file_and_path_for_module(modulename):
+    """Find the file and search path for `modulename`.
+
+    Returns:
+        filename: The filename of the module, or None.
+        path: A list (possibly empty) of directories to find submodules in.
+
+    """
     filename = None
+    path = []
     try:
         spec = importlib.util.find_spec(modulename)
     except ImportError:
         pass
     else:
         if spec is not None:
-            filename = spec.origin
-    return filename
+            if spec.origin != "namespace":
+                filename = spec.origin
+            path = list(spec.submodule_search_locations or ())
+    return filename, path
 
 
 def add_stdlib_paths(paths):
@@ -263,15 +272,29 @@ class InOrOut:
         # third-party package.
         for pkg in self.source_pkgs:
             try:
-                modfile = file_for_module(pkg)
-                debug(f"Imported {pkg} as {modfile}")
+                modfile, path = file_and_path_for_module(pkg)
+                debug(f"Imported source package {pkg!r} as {modfile!r}")
             except CoverageException as exc:
-                debug(f"Couldn't import {pkg}: {exc}")
+                debug(f"Couldn't import source package {pkg!r}: {exc}")
                 continue
-            if modfile and self.third_match.match(modfile):
-                self.source_in_third = True
+            if modfile:
+                if self.third_match.match(modfile):
+                    debug(
+                        f"Source is in third-party because of source_pkg {pkg!r} at {modfile!r}"
+                    )
+                    self.source_in_third = True
+            else:
+                for pathdir in path:
+                    if self.third_match.match(pathdir):
+                        debug(
+                            f"Source is in third-party because of {pkg!r} path directory " +
+                            f"at {pathdir!r}"
+                        )
+                        self.source_in_third = True
+
         for src in self.source:
             if self.third_match.match(src):
+                debug(f"Source is in third-party because of source directory {src!r}")
                 self.source_in_third = True
 
     def should_trace(self, filename, frame=None):
diff --git a/tests/test_process.py b/tests/test_process.py
index 72b47d4e..781a0170 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -1691,13 +1691,37 @@ def venv_world_fixture(tmp_path_factory):
             def fourth(x):
                 return 4 * x
             """)
+        # Some namespace packages.
+        make_file("third_pkg/nspkg/fifth/__init__.py", """\
+            def fifth(x):
+                return 5 * x
+            """)
+        # The setup.py to install everything.
         make_file("third_pkg/setup.py", """\
             import setuptools
-            setuptools.setup(name="third", packages=["third", "fourth"])
+            setuptools.setup(
+                name="third",
+                packages=["third", "fourth", "nspkg.fifth"],
+            )
+            """)
+
+        # Some namespace packages.
+        make_file("another_pkg/nspkg/sixth/__init__.py", """\
+            def sixth(x):
+                return 6 * x
+            """)
+        # The setup.py to install everything.
+        make_file("another_pkg/setup.py", """\
+            import setuptools
+            setuptools.setup(
+                name="another",
+                packages=["nspkg.sixth"],
+            )
             """)
 
         # Install the third-party packages.
         run_in_venv("python -m pip install --no-index ./third_pkg")
+        run_in_venv("python -m pip install --no-index -e ./another_pkg")
         shutil.rmtree("third_pkg")
 
         # Install coverage.
@@ -1719,6 +1743,8 @@ def coverage_command_fixture(request):
 class VirtualenvTest(CoverageTest):
     """Tests of virtualenv considerations."""
 
+    expected_stdout = "33\n110\n198\n1.5\n"
+
     @pytest.fixture(autouse=True)
     def in_venv_world_fixture(self, venv_world):
         """For running tests inside venv_world, and cleaning up made files."""
@@ -1726,10 +1752,13 @@ class VirtualenvTest(CoverageTest):
             self.make_file("myproduct.py", """\
                 import colorsys
                 import third
+                import nspkg.fifth
+                import nspkg.sixth
                 print(third.third(11))
+                print(nspkg.fifth.fifth(22))
+                print(nspkg.sixth.sixth(33))
                 print(sum(colorsys.rgb_to_hls(1, 0, 0)))
                 """)
-            self.expected_stdout = "33\n1.5\n"      # pylint: disable=attribute-defined-outside-init
 
             self.del_environ("COVERAGE_TESTING")    # To avoid needing contracts installed.
             self.set_environ("COVERAGE_DEBUG_FILE", "debug_out.txt")
@@ -1738,7 +1767,7 @@ class VirtualenvTest(CoverageTest):
             yield
 
             for fname in os.listdir("."):
-                if fname != "venv":
+                if fname not in {"venv", "another_pkg"}:
                     os.remove(fname)
 
     def get_trace_output(self):
@@ -1829,3 +1858,45 @@ class VirtualenvTest(CoverageTest):
         # The output should not have this warning:
         # Already imported a file that will be measured: ...third/render.py (already-imported)
         assert out == "HTML: hello.html@1723\n"
+
+    def test_installed_namespace_packages(self, coverage_command):
+        # https://github.com/nedbat/coveragepy/issues/1231
+        # When namespace packages were installed, they were considered
+        # third-party packages.  Test that isn't still happening.
+        out = run_in_venv(coverage_command + " run --source=nspkg myproduct.py")
+        # In particular, this warning doesn't appear:
+        # Already imported a file that will be measured: .../coverage/__main__.py
+        assert out == self.expected_stdout
+
+        # Check that our tracing was accurate. Files are mentioned because
+        # --source refers to a file.
+        debug_out = self.get_trace_output()
+        assert re_lines(
+            debug_out,
+            r"^Not tracing .*\bexecfile.py': " +
+            "module 'coverage.execfile' falls outside the --source spec"
+            )
+        assert re_lines(
+            debug_out,
+            r"^Not tracing .*\bmyproduct.py': module 'myproduct' falls outside the --source spec"
+            )
+        assert re_lines(
+            debug_out,
+            r"^Not tracing .*\bcolorsys.py': module 'colorsys' falls outside the --source spec"
+            )
+
+        out = run_in_venv("python -m coverage report")
+
+        # Name                                                       Stmts   Miss  Cover
+        # ------------------------------------------------------------------------------
+        # another_pkg/nspkg/sixth/__init__.py                            2      0   100%
+        # venv/lib/python3.9/site-packages/nspkg/fifth/__init__.py       2      0   100%
+        # ------------------------------------------------------------------------------
+        # TOTAL                                                          4      0   100%
+
+        assert "myproduct.py" not in out
+        assert "third" not in out
+        assert "coverage" not in out
+        assert "colorsys" not in out
+        assert "fifth" in out
+        assert "sixth" in out