Don't warn that namespace packages have no code. #572

5 files changed, 57 insertions, 16 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 4aac4a4..fd2d7b8 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -14,6 +14,9 @@ Unreleased
   instead of the correct ``pkg/__init__.py``.  This is now fixed, closing
   `issue 526`_.  Thanks, Dirk Thomas.
 
+- Namespace packages are no longer warned as having no code, as described in
+  `issue 572`_.
+
 - Code that uses ``sys.settrace(sys.gettrace())`` in a file that wasn't being
   coverage-measured would prevent correct coverage measurement in following
   code. An example of this was running doctests programmatically, as described
@@ -26,6 +29,7 @@ Unreleased
   fail under Python 2, as reported in `issue 573`_. This is now fixed.
 
 .. _issue 526: https://bitbucket.org/ned/coveragepy/issues/526/generated-xml-invalid-paths-for-cobertura
+.. _issue 572: https://bitbucket.org/ned/coveragepy/issues/572/no-python-source-warning-for-namespace
 .. _issue 573: https://bitbucket.org/ned/coveragepy/issues/573/cant-generate-xml-report-if-some-source
 .. _issue 575: https://bitbucket.org/ned/coveragepy/issues/575/running-doctest-prevents-complete-coverage
 
diff --git a/coverage/control.py b/coverage/control.py
index fb03361..2cbe491 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -837,18 +837,7 @@ class Coverage(object):
         # then we never encountered those packages.
         if self._warn_unimported_source:
             for pkg in self.source_pkgs_unmatched:
-                if pkg not in sys.modules:
-                    self._warn("Module %s was never imported." % pkg, slug="module-not-imported")
-                elif not (
-                    hasattr(sys.modules[pkg], '__file__') and
-                    os.path.exists(sys.modules[pkg].__file__)
-                ):
-                    self._warn("Module %s has no Python source." % pkg, slug="module-not-python")
-                else:
-                    self._warn(
-                        "Module %s was previously imported, but not measured." % pkg,
-                        slug="module-not-measured",
-                    )
+                self._warn_about_unmeasured_code(pkg)
 
         # Find out if we got any data.
         if not self.data and self._warn_no_data:
@@ -869,6 +858,37 @@ class Coverage(object):
         if self.config.note:
             self.data.add_run_info(note=self.config.note)
 
+    def _warn_about_unmeasured_code(self, pkg):
+        """Warn about a package or module that we never traced.
+
+        `pkg` is a string, the name of the package or module.
+
+        """
+        mod = sys.modules.get(pkg)
+        if mod is None:
+            self._warn("Module %s was never imported." % pkg, slug="module-not-imported")
+            return
+
+        is_namespace = hasattr(mod, '__path__') and not hasattr(mod, '__file__')
+        has_file = hasattr(mod, '__file__') and os.path.exists(mod.__file__)
+
+        if is_namespace:
+            # A namespace package. It's OK for this not to have been traced,
+            # since there is no code directly in it.
+            return
+
+        if not has_file:
+            self._warn("Module %s has no Python source." % pkg, slug="module-not-python")
+            return
+
+        # The module was in sys.modules, and seems like a module with code, but
+        # we never measured it. I guess that means it was imported before
+        # coverage even started.
+        self._warn(
+            "Module %s was previously imported, but not measured." % pkg,
+            slug="module-not-measured",
+        )
+
     def _find_plugin_files(self, src_dir):
         """Get executable files from the plugins."""
         for plugin in self.plugins:
diff --git a/tests/modules/namespace_420/sub1/__init__.py b/tests/modules/namespace_420/sub1/__init__.py
new file mode 100644
index 0000000..94bb295
--- /dev/null
+++ b/tests/modules/namespace_420/sub1/__init__.py
@@ -0,0 +1,4 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
+
+sub1 = "namespace_420 sub1"
diff --git a/tests/moremodules/namespace_420/sub2/__init__.py b/tests/moremodules/namespace_420/sub2/__init__.py
new file mode 100644
index 0000000..0839688
--- /dev/null
+++ b/tests/moremodules/namespace_420/sub2/__init__.py
@@ -0,0 +1,4 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
+
+sub2 = "namespace_420 sub2"
diff --git a/tests/test_api.py b/tests/test_api.py
index 90f9654..3a06da3 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -445,7 +445,7 @@ class ApiTest(CoverageTest):
         self.assertNotIn("no-data-collected", err)
 
 
-class NamespaceModuleTest(CoverageTest):
+class NamespaceModuleTest(UsingModulesMixin, CoverageTest):
     """Test PEP-420 namespace modules."""
 
     def setUp(self):
@@ -454,14 +454,23 @@ class NamespaceModuleTest(CoverageTest):
             self.skipTest("Python before 3.3 doesn't have namespace packages")
 
     def test_explicit_namespace_module(self):
-        self.make_file("namespace/package/module.py", "VAR = 1\n")
-        self.make_file("main.py", "import namespace\n")
+        self.make_file("main.py", "import namespace_420\n")
 
         cov = coverage.Coverage()
         self.start_import_stop(cov, "main")
 
         with self.assertRaisesRegex(CoverageException, r"Module .* has no file"):
-            cov.analysis(sys.modules['namespace'])
+            cov.analysis(sys.modules['namespace_420'])
+
+    def test_bug_572(self):
+        self.make_file("main.py", "import namespace_420\n")
+
+        # Use source=namespace_420 to trigger the check that used to fail,
+        # and use source=main so that something is measured.
+        cov = coverage.Coverage(source=["namespace_420", "main"])
+        with self.assert_warnings(cov, []):
+            self.start_import_stop(cov, "main")
+            cov.report()
 
 
 class OmitIncludeTestsMixin(UsingModulesMixin, CoverageTestMethodsMixin):