[1.7.X] Fixed #22557 -- ManifestStaticFilesStorage did not cleanup deleted files.

When using ManifestStaticFilesStorage, deleted static files would be
correctly cleaned up by "collectstatic --clear", but the manifest file
would still contain the stale entries.

Thanks to tedtieken for the report

Backport of 3bec3888 from master.

django/contrib/staticfiles/storage.py

@@ -312,10 +312,14 @@ class ManifestFilesMixin(HashedFilesMixin):
                          (self.manifest_name, self.manifest_version))
 
     def post_process(self, *args, **kwargs):
+        self.hashed_files = OrderedDict()
         all_post_processed = super(ManifestFilesMixin,
                                    self).post_process(*args, **kwargs)
         for post_processed in all_post_processed:
             yield post_processed
+        self.save_manifest()
+
+    def save_manifest(self):
         payload = {'paths': self.hashed_files, 'version': self.manifest_version}
         if self.exists(self.manifest_name):
             self.delete(self.manifest_name)

tests/staticfiles_tests/tests.py

@@ -59,15 +59,15 @@ class BaseStaticFilesTestCase(object):
         # run and pick up changes in settings.STATICFILES_DIRS.
         finders.get_finder.cache_clear()
 
-        testfiles_path = os.path.join(TEST_ROOT, 'apps', 'test', 'static', 'test')
+        self.testfiles_path = os.path.join(TEST_ROOT, 'apps', 'test', 'static', 'test')
         # To make sure SVN doesn't hangs itself with the non-ASCII characters
         # during checkout, we actually create one file dynamically.
-        self._nonascii_filepath = os.path.join(testfiles_path, '\u2297.txt')
+        self._nonascii_filepath = os.path.join(self.testfiles_path, '\u2297.txt')
         with codecs.open(self._nonascii_filepath, 'w', 'utf-8') as f:
             f.write("\u2297 in the app dir")
         # And also create the stupid hidden file to dwarf the setup.py's
         # package data handling.
-        self._hidden_filepath = os.path.join(testfiles_path, '.hidden')
+        self._hidden_filepath = os.path.join(self.testfiles_path, '.hidden')
         with codecs.open(self._hidden_filepath, 'w', 'utf-8') as f:
             f.write("should be ignored")
         self._backup_filepath = os.path.join(
@@ -652,6 +652,19 @@ class TestCollectionManifestStorage(TestHashedFiles, BaseCollectionTestCase,
     """
     Tests for the Cache busting storage
     """
+
+    def setUp(self):
+        super(TestCollectionManifestStorage, self).setUp()
+
+        self._clear_filename = os.path.join(self.testfiles_path, 'cleared.txt')
+        with open(self._clear_filename, 'w') as f:
+            f.write('to be deleted in one test')
+
+    def tearDown(self):
+        super(TestCollectionManifestStorage, self).tearDown()
+        if os.path.exists(self._clear_filename):
+            os.unlink(self._clear_filename)
+
     def test_manifest_exists(self):
         filename = storage.staticfiles_storage.manifest_name
         path = storage.staticfiles_storage.path(filename)
@@ -669,6 +682,31 @@ class TestCollectionManifestStorage(TestHashedFiles, BaseCollectionTestCase,
         manifest = storage.staticfiles_storage.load_manifest()
         self.assertEqual(hashed_files, manifest)
 
+    def test_clear_empties_manifest(self):
+        # collect the additional file
+        self.run_collectstatic()
+
+        hashed_files = storage.staticfiles_storage.hashed_files
+        self.assertIn('test/cleared.txt', hashed_files)
+
+        manifest_content = storage.staticfiles_storage.load_manifest()
+        self.assertIn('test/cleared.txt', manifest_content)
+
+        original_path = storage.staticfiles_storage.path('test/cleared.txt')
+        self.assertTrue(os.path.exists(original_path))
+
+        # delete the original file form the app, collect with clear
+        os.unlink(self._clear_filename)
+        self.run_collectstatic(clear=True)
+
+        self.assertFileNotFound(original_path)
+
+        hashed_files = storage.staticfiles_storage.hashed_files
+        self.assertNotIn('test/cleared.txt', hashed_files)
+
+        manifest_content = storage.staticfiles_storage.load_manifest()
+        self.assertNotIn('test/cleared.txt', manifest_content)
+
 
 # we set DEBUG to False here since the template tag wouldn't work otherwise
 @override_settings(**dict(