Fixed #24452 -- Fixed HashedFilesMixin correctness with nested paths.

6 files changed, 342 insertions, 50 deletions

diff --git a/django/contrib/staticfiles/storage.py b/django/contrib/staticfiles/storage.py
index a1d787548a..da0d2004e6 100644
--- a/django/contrib/staticfiles/storage.py
+++ b/django/contrib/staticfiles/storage.py
@@ -18,6 +18,7 @@ from django.core.files.storage import FileSystemStorage, get_storage_class
 from django.utils.encoding import force_bytes, force_text
 from django.utils.functional import LazyObject
 from django.utils.six import iteritems
+from django.utils.six.moves import range
 from django.utils.six.moves.urllib.parse import (
     unquote, urldefrag, urlsplit, urlunsplit,
 )
@@ -54,6 +55,7 @@ class StaticFilesStorage(FileSystemStorage):
 
 class HashedFilesMixin(object):
     default_template = """url("%s")"""
+    max_post_process_passes = 5
     patterns = (
         ("*.css", (
             r"""(url\(['"]{0,1}\s*(.*?)["']{0,1}\))""",
@@ -85,16 +87,20 @@ class HashedFilesMixin(object):
             md5.update(chunk)
         return md5.hexdigest()[:12]
 
-    def hashed_name(self, name, content=None):
+    def hashed_name(self, name, content=None, filename=None):
+        # `filename` is the name of file to hash if `content` isn't given.
+        # `name` is the base name to construct the new hashed filename from.
         parsed_name = urlsplit(unquote(name))
         clean_name = parsed_name.path.strip()
+        if filename:
+            filename = urlsplit(unquote(filename)).path.strip()
+        filename = filename or clean_name
         opened = False
         if content is None:
-            if not self.exists(clean_name):
-                raise ValueError("The file '%s' could not be found with %r." %
-                                 (clean_name, self))
+            if not self.exists(filename):
+                raise ValueError("The file '%s' could not be found with %r." % (filename, self))
             try:
-                content = self.open(clean_name)
+                content = self.open(filename)
             except IOError:
                 # Handle directory paths and fragments
                 return name
@@ -118,9 +124,9 @@ class HashedFilesMixin(object):
             unparsed_name[2] += '?'
         return urlunsplit(unparsed_name)
 
-    def url(self, name, force=False):
+    def _url(self, hashed_name_func, name, force=False, hashed_files=None):
         """
-        Return the real URL in DEBUG mode.
+        Return the non-hashed URL in DEBUG mode.
         """
         if settings.DEBUG and not force:
             hashed_name, fragment = name, ''
@@ -129,7 +135,10 @@ class HashedFilesMixin(object):
             if urlsplit(clean_name).path.endswith('/'):  # don't hash paths
                 hashed_name = name
             else:
-                hashed_name = self.stored_name(clean_name)
+                args = (clean_name,)
+                if hashed_files is not None:
+                    args += (hashed_files,)
+                hashed_name = hashed_name_func(*args)
 
         final_url = super(HashedFilesMixin, self).url(hashed_name)
 
@@ -146,7 +155,13 @@ class HashedFilesMixin(object):
 
         return unquote(final_url)
 
-    def url_converter(self, name, template=None):
+    def url(self, name, force=False):
+        """
+        Return the non-hashed URL in DEBUG mode.
+        """
+        return self._url(self.stored_name, name, force)
+
+    def url_converter(self, name, hashed_files, template=None):
         """
         Return the custom URL converter for the given file name.
         """
@@ -184,7 +199,10 @@ class HashedFilesMixin(object):
                 target_name = posixpath.join(posixpath.dirname(source_name), url_path)
 
             # Determine the hashed name of the target file with the storage backend.
-            hashed_url = self.url(unquote(target_name), force=True)
+            hashed_url = self._url(
+                self._stored_name, unquote(target_name),
+                force=True, hashed_files=hashed_files,
+            )
 
             transformed_url = '/'.join(url_path.split('/')[:-1] + hashed_url.split('/')[-1:])
 
@@ -223,21 +241,48 @@ class HashedFilesMixin(object):
             path for path in paths
             if matches_patterns(path, self._patterns.keys())
         ]
+        # Do a single pass first. Post-process all files once, then repeat for
+        # adjustable files.
+        for name, hashed_name, processed, _ in self._post_process(paths, adjustable_paths, hashed_files):
+            yield name, hashed_name, processed
+
+        paths = {path: paths[path] for path in adjustable_paths}
 
-        # then sort the files by the directory level
+        for i in range(self.max_post_process_passes):
+            substitutions = False
+            for name, hashed_name, processed, subst in self._post_process(paths, adjustable_paths, hashed_files):
+                yield name, hashed_name, processed
+                substitutions = substitutions or subst
+
+            if not substitutions:
+                break
+
+        if substitutions:
+            yield 'All', None, RuntimeError('Max post-process passes exceeded.')
+
+        # Store the processed paths
+        self.hashed_files.update(hashed_files)
+
+    def _post_process(self, paths, adjustable_paths, hashed_files):
+        # Sort the files by directory level
         def path_level(name):
             return len(name.split(os.sep))
 
         for name in sorted(paths.keys(), key=path_level, reverse=True):
-
+            substitutions = True
             # use the original, local file, not the copied-but-unprocessed
             # file, which might be somewhere far away, like S3
             storage, path = paths[name]
             with storage.open(path) as original_file:
+                cleaned_name = self.clean_name(name)
+                hash_key = self.hash_key(cleaned_name)
 
                 # generate the hash with the original content, even for
                 # adjustable files.
-                hashed_name = self.hashed_name(name, original_file)
+                if hash_key not in hashed_files:
+                    hashed_name = self.hashed_name(name, original_file)
+                else:
+                    hashed_name = hashed_files[hash_key]
 
                 # then get the original's file content..
                 if hasattr(original_file, 'seek'):
@@ -248,23 +293,35 @@ class HashedFilesMixin(object):
 
                 # ..to apply each replacement pattern to the content
                 if name in adjustable_paths:
+                    old_hashed_name = hashed_name
                     content = original_file.read().decode(settings.FILE_CHARSET)
                     for extension, patterns in iteritems(self._patterns):
                         if matches_patterns(path, (extension,)):
                             for pattern, template in patterns:
-                                converter = self.url_converter(name, template)
+                                converter = self.url_converter(name, hashed_files, template)
                                 try:
                                     content = pattern.sub(converter, content)
                                 except ValueError as exc:
-                                    yield name, None, exc
+                                    yield name, None, exc, False
                     if hashed_file_exists:
                         self.delete(hashed_name)
                     # then save the processed result
                     content_file = ContentFile(force_bytes(content))
+                    # Save intermediate file for reference
+                    saved_name = self._save(hashed_name, content_file)
+                    hashed_name = self.hashed_name(name, content_file)
+
+                    if self.exists(hashed_name):
+                        self.delete(hashed_name)
+
                     saved_name = self._save(hashed_name, content_file)
                     hashed_name = force_text(self.clean_name(saved_name))
+                    # If the file hash stayed the same, this file didn't change
+                    if old_hashed_name == hashed_name:
+                        substitutions = False
                     processed = True
-                else:
+
+                if not processed:
                     # or handle the case in which neither processing nor
                     # a change to the original file happened
                     if not hashed_file_exists:
@@ -273,11 +330,9 @@ class HashedFilesMixin(object):
                         hashed_name = force_text(self.clean_name(saved_name))
 
                 # and then set the cache accordingly
-                hashed_files[self.hash_key(name)] = hashed_name
-                yield name, hashed_name, processed
+                hashed_files[hash_key] = hashed_name
 
-        # Finally store the processed paths
-        self.hashed_files.update(hashed_files)
+                yield name, hashed_name, processed, substitutions
 
     def clean_name(self, name):
         return name.replace('\\', '/')
@@ -285,20 +340,46 @@ class HashedFilesMixin(object):
     def hash_key(self, name):
         return name
 
-    def stored_name(self, name):
-        hash_key = self.hash_key(name)
-        cache_name = self.hashed_files.get(hash_key)
+    def _stored_name(self, name, hashed_files):
+        # Normalize the path to avoid multiple names for the same file like
+        # ../foo/bar.css and ../foo/../foo/bar.css which normalize to the same
+        # path.
+        name = posixpath.normpath(name)
+        cleaned_name = self.clean_name(name)
+        hash_key = self.hash_key(cleaned_name)
+        cache_name = hashed_files.get(hash_key)
         if cache_name is None:
             cache_name = self.clean_name(self.hashed_name(name))
-            # store the hashed name if there was a miss, e.g.
-            # when the files are still processed
-            self.hashed_files[hash_key] = cache_name
         return cache_name
 
+    def stored_name(self, name):
+        cleaned_name = self.clean_name(name)
+        hash_key = self.hash_key(cleaned_name)
+        cache_name = self.hashed_files.get(hash_key)
+        if cache_name:
+            return cache_name
+        # No cached name found, recalculate it from the files.
+        intermediate_name = name
+        for i in range(self.max_post_process_passes + 1):
+            cache_name = self.clean_name(
+                self.hashed_name(name, content=None, filename=intermediate_name)
+            )
+            if intermediate_name == cache_name:
+                # Store the hashed name if there was a miss.
+                self.hashed_files[hash_key] = cache_name
+                return cache_name
+            else:
+                # Move on to the next intermediate file.
+                intermediate_name = cache_name
+        # If the cache name can't be determined after the max number of passes,
+        # the intermediate files on disk may be corrupt; avoid an infinite loop.
+        raise ValueError("The name '%s' could not be hashed with %r." % (name, self))
+
 
 class ManifestFilesMixin(HashedFilesMixin):
     manifest_version = '1.0'  # the manifest format standard
     manifest_name = 'staticfiles.json'
+    manifest_strict = True
 
     def __init__(self, *args, **kwargs):
         super(ManifestFilesMixin, self).__init__(*args, **kwargs)
@@ -341,6 +422,23 @@ class ManifestFilesMixin(HashedFilesMixin):
         contents = json.dumps(payload).encode('utf-8')
         self._save(self.manifest_name, ContentFile(contents))
 
+    def stored_name(self, name):
+        parsed_name = urlsplit(unquote(name))
+        clean_name = parsed_name.path.strip()
+        hash_key = self.hash_key(clean_name)
+        cache_name = self.hashed_files.get(hash_key)
+        if cache_name is None:
+            if self.manifest_strict:
+                raise ValueError("Missing staticfiles manifest entry for '%s'" % clean_name)
+            cache_name = self.clean_name(self.hashed_name(name))
+        unparsed_name = list(parsed_name)
+        unparsed_name[2] = cache_name
+        # Special casing for a @font-face hack, like url(myfont.eot?#iefix")
+        # http://www.fontspring.com/blog/the-new-bulletproof-font-face-syntax
+        if '?#' in name and not unparsed_name[3]:
+            unparsed_name[2] += '?'
+        return urlunsplit(unparsed_name)
+
 
 class _MappingCache(object):
     """
diff --git a/docs/ref/contrib/staticfiles.txt b/docs/ref/contrib/staticfiles.txt
index 1c6e36515a..b8d91fddb8 100644
--- a/docs/ref/contrib/staticfiles.txt
+++ b/docs/ref/contrib/staticfiles.txt
@@ -293,6 +293,24 @@ content:
 
     @import url("../admin/css/base.27e20196a850.css");
 
+.. attribute:: storage.ManifestStaticFilesStorage.max_post_process_passes
+
+Since static files might reference other static files that need to have their
+paths replaced, multiple passes of replacing paths may be needed until the file
+hashes converge. To prevent an infinite loop due to hashes not converging (for
+example, if ``'foo.css'`` references ``'bar.css'`` which references
+``'foo.css'``) there is a maximum number of passes before post-processing is
+abandoned. In cases with a large number of references, a higher number of
+passes might be needed. Increase the maximum number of passes by subclassing
+``ManifestStaticFilesStorage`` and setting the ``max_post_process_passes``
+attribute. It defaults to 5.
+
+.. versionchanged:: 1.11
+
+    Previous versions didn't make multiple passes to ensure file hashes
+    converged, so often times file hashes weren't correct. The
+    ``max_post_process_passes`` attribute was added.
+
 To enable the ``ManifestStaticFilesStorage`` you have to make sure the
 following requirements are met:
 
@@ -315,6 +333,18 @@ hashed names for all processed files in a file called ``staticfiles.json``.
 This happens once when you run the :djadmin:`collectstatic` management
 command.
 
+.. attribute:: storage.ManifestStaticFilesStorage.manifest_strict
+
+If a file isn't found in the ``staticfiles.json`` manifest at runtime, a
+``ValueError`` is raised. This behavior can be disabled by subclassing
+``ManifestStaticFilesStorage`` and setting the ``manifest_strict`` attribute to
+``False`` -- nonexistent paths will remain unchanged.
+
+.. versionchanged:: 1.11
+
+    The ``manifest_strict`` attribute was added. In older versions, the
+    behavior is the same as ``manifest_strict=False``.
+
 Due to the requirement of running :djadmin:`collectstatic`, this storage
 typically shouldn't be used when running tests as ``collectstatic`` isn't run
 as part of the normal test setup. During testing, ensure that the
@@ -350,6 +380,16 @@ If you want to override certain options of the cache backend the storage uses,
 simply specify a custom entry in the :setting:`CACHES` setting named
 ``'staticfiles'``. It falls back to using the ``'default'`` cache backend.
 
+.. warning::
+
+    ``CachedStaticFilesStorage`` isn't recommended --  in almost all cases
+    ``ManifestStaticFilesStorage`` is a better choice. There are several
+    performance penalties when using ``CachedStaticFilesStorage`` since a cache
+    miss requires hashing files at runtime. Remote file storage require several
+    round-trips to hash a file on a cache miss, as several file accesses are
+    required to ensure that the file hash is correct in the case of nested file
+    paths.
+
 Finders Module
 ==============
 
diff --git a/docs/releases/1.11.txt b/docs/releases/1.11.txt
index 0ccecd9dba..9be1f4c53d 100644
--- a/docs/releases/1.11.txt
+++ b/docs/releases/1.11.txt
@@ -481,6 +481,21 @@ Backwards incompatible changes in 1.11
   updated. Check your project if you subclass these widgets or extend the
   templates.
 
+:mod:`django.contrib.staticfiles`
+---------------------------------
+
+* ``collectstatic`` may now fail during post-processing when using a hashed
+  static files storage if a reference loop exists (e.g. ``'foo.css'``
+  references ``'bar.css'`` which itself references ``'foo.css'``) or if the
+  chain of files referencing other files is too deep to resolve in several
+  passes. In the latter case, increase the number of passes using
+  :attr:`.ManifestStaticFilesStorage.max_post_process_passes`.
+
+* When using ``ManifestStaticFilesStorage``, static files not found in the
+  manifest at runtime now raise a ``ValueError`` instead of returning an
+  unchanged path. You can revert to the old behavior by setting
+  :attr:`.ManifestStaticFilesStorage.manifest_strict` to ``False``.
+
 Database backend API
 --------------------
 
diff --git a/tests/staticfiles_tests/project/loop/bar.css b/tests/staticfiles_tests/project/loop/bar.css
new file mode 100644
index 0000000000..1f11a22cbf
--- /dev/null
+++ b/tests/staticfiles_tests/project/loop/bar.css
@@ -0,0 +1 @@
+@import url("foo.css")
diff --git a/tests/staticfiles_tests/project/loop/foo.css b/tests/staticfiles_tests/project/loop/foo.css
new file mode 100644
index 0000000000..0903a70802
--- /dev/null
+++ b/tests/staticfiles_tests/project/loop/foo.css
@@ -0,0 +1 @@
+@import url("bar.css")
diff --git a/tests/staticfiles_tests/test_storage.py b/tests/staticfiles_tests/test_storage.py
index c0fed0e4ae..4e1dec84f9 100644
--- a/tests/staticfiles_tests/test_storage.py
+++ b/tests/staticfiles_tests/test_storage.py
@@ -28,9 +28,21 @@ def hashed_file_path(test, path):
 class TestHashedFiles(object):
     hashed_file_path = hashed_file_path
 
+    def setUp(self):
+        self._max_post_process_passes = storage.staticfiles_storage.max_post_process_passes
+        super(TestHashedFiles, self).setUp()
+
     def tearDown(self):
         # Clear hashed files to avoid side effects among tests.
         storage.staticfiles_storage.hashed_files.clear()
+        storage.staticfiles_storage.max_post_process_passes = self._max_post_process_passes
+
+    def assertPostCondition(self):
+        """
+        Assert post conditions for a test are met. Must be manually called at
+        the end of each test.
+        """
+        pass
 
     def test_template_tag_return(self):
         """
@@ -39,17 +51,19 @@ class TestHashedFiles(object):
         self.assertStaticRaises(ValueError, "does/not/exist.png", "/static/does/not/exist.png")
         self.assertStaticRenders("test/file.txt", "/static/test/file.dad0999e4f8f.txt")
         self.assertStaticRenders("test/file.txt", "/static/test/file.dad0999e4f8f.txt", asvar=True)
-        self.assertStaticRenders("cached/styles.css", "/static/cached/styles.bb84a0240107.css")
+        self.assertStaticRenders("cached/styles.css", "/static/cached/styles.5e0040571e1a.css")
         self.assertStaticRenders("path/", "/static/path/")
         self.assertStaticRenders("path/?query", "/static/path/?query")
+        self.assertPostCondition()
 
     def test_template_tag_simple_content(self):
         relpath = self.hashed_file_path("cached/styles.css")
-        self.assertEqual(relpath, "cached/styles.bb84a0240107.css")
+        self.assertEqual(relpath, "cached/styles.5e0040571e1a.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b"cached/other.css", content)
             self.assertIn(b"other.d41d8cd98f00.css", content)
+        self.assertPostCondition()
 
     def test_path_ignored_completely(self):
         relpath = self.hashed_file_path("cached/css/ignored.css")
@@ -62,28 +76,29 @@ class TestHashedFiles(object):
             self.assertIn(b'data:foobar', content)
             self.assertIn(b'chrome:foobar', content)
             self.assertIn(b'//foobar', content)
+        self.assertPostCondition()
 
     def test_path_with_querystring(self):
         relpath = self.hashed_file_path("cached/styles.css?spam=eggs")
-        self.assertEqual(relpath, "cached/styles.bb84a0240107.css?spam=eggs")
-        with storage.staticfiles_storage.open(
-                "cached/styles.bb84a0240107.css") as relfile:
+        self.assertEqual(relpath, "cached/styles.5e0040571e1a.css?spam=eggs")
+        with storage.staticfiles_storage.open("cached/styles.5e0040571e1a.css") as relfile:
             content = relfile.read()
             self.assertNotIn(b"cached/other.css", content)
             self.assertIn(b"other.d41d8cd98f00.css", content)
+        self.assertPostCondition()
 
     def test_path_with_fragment(self):
         relpath = self.hashed_file_path("cached/styles.css#eggs")
-        self.assertEqual(relpath, "cached/styles.bb84a0240107.css#eggs")
-        with storage.staticfiles_storage.open(
-                "cached/styles.bb84a0240107.css") as relfile:
+        self.assertEqual(relpath, "cached/styles.5e0040571e1a.css#eggs")
+        with storage.staticfiles_storage.open("cached/styles.5e0040571e1a.css") as relfile:
             content = relfile.read()
             self.assertNotIn(b"cached/other.css", content)
             self.assertIn(b"other.d41d8cd98f00.css", content)
+        self.assertPostCondition()
 
     def test_path_with_querystring_and_fragment(self):
         relpath = self.hashed_file_path("cached/css/fragments.css")
-        self.assertEqual(relpath, "cached/css/fragments.59dc2b188043.css")
+        self.assertEqual(relpath, "cached/css/fragments.c4e6753b52d3.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertIn(b'fonts/font.a4b0478549d0.eot?#iefix', content)
@@ -91,60 +106,79 @@ class TestHashedFiles(object):
             self.assertIn(b'fonts/font.b8d603e42714.svg#path/to/../../fonts/font.svg', content)
             self.assertIn(b'data:font/woff;charset=utf-8;base64,d09GRgABAAAAADJoAA0AAAAAR2QAAQAAAAAAAAAAAAA', content)
             self.assertIn(b'#default#VML', content)
+        self.assertPostCondition()
 
     def test_template_tag_absolute(self):
         relpath = self.hashed_file_path("cached/absolute.css")
-        self.assertEqual(relpath, "cached/absolute.df312c6326e1.css")
+        self.assertEqual(relpath, "cached/absolute.eb04def9f9a4.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b"/static/cached/styles.css", content)
-            self.assertIn(b"/static/cached/styles.bb84a0240107.css", content)
+            self.assertIn(b"/static/cached/styles.5e0040571e1a.css", content)
             self.assertNotIn(b"/static/styles_root.css", content)
             self.assertIn(b"/static/styles_root.401f2509a628.css", content)
             self.assertIn(b'/static/cached/img/relative.acae32e4532b.png', content)
+        self.assertPostCondition()
 
     def test_template_tag_absolute_root(self):
         """
         Like test_template_tag_absolute, but for a file in STATIC_ROOT (#26249).
         """
         relpath = self.hashed_file_path("absolute_root.css")
-        self.assertEqual(relpath, "absolute_root.f864a4d7f083.css")
+        self.assertEqual(relpath, "absolute_root.f821df1b64f7.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b"/static/styles_root.css", content)
             self.assertIn(b"/static/styles_root.401f2509a628.css", content)
+        self.assertPostCondition()
 
     def test_template_tag_relative(self):
         relpath = self.hashed_file_path("cached/relative.css")
-        self.assertEqual(relpath, "cached/relative.b0375bd89156.css")
+        self.assertEqual(relpath, "cached/relative.c3e9e1ea6f2e.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b"../cached/styles.css", content)
             self.assertNotIn(b'@import "styles.css"', content)
             self.assertNotIn(b'url(img/relative.png)', content)
             self.assertIn(b'url("img/relative.acae32e4532b.png")', content)
-            self.assertIn(b"../cached/styles.bb84a0240107.css", content)
+            self.assertIn(b"../cached/styles.5e0040571e1a.css", content)
+        self.assertPostCondition()
 
     def test_import_replacement(self):
         "See #18050"
         relpath = self.hashed_file_path("cached/import.css")
-        self.assertEqual(relpath, "cached/import.2b1d40b0bbd4.css")
+        self.assertEqual(relpath, "cached/import.f53576679e5a.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
-            self.assertIn(b"""import url("styles.bb84a0240107.css")""", relfile.read())
+            self.assertIn(b"""import url("styles.5e0040571e1a.css")""", relfile.read())
+        self.assertPostCondition()
 
     def test_template_tag_deep_relative(self):
         relpath = self.hashed_file_path("cached/css/window.css")
-        self.assertEqual(relpath, "cached/css/window.3906afbb5a17.css")
+        self.assertEqual(relpath, "cached/css/window.5d5c10836967.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b'url(img/window.png)', content)
             self.assertIn(b'url("img/window.acae32e4532b.png")', content)
+        self.assertPostCondition()
 
     def test_template_tag_url(self):
         relpath = self.hashed_file_path("cached/url.css")
         self.assertEqual(relpath, "cached/url.902310b73412.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             self.assertIn(b"https://", relfile.read())
+        self.assertPostCondition()
+
+    @override_settings(
+        STATICFILES_DIRS=[os.path.join(TEST_ROOT, 'project', 'loop')],
+        STATICFILES_FINDERS=['django.contrib.staticfiles.finders.FileSystemFinder'],
+    )
+    def test_import_loop(self):
+        finders.get_finder.cache_clear()
+        err = six.StringIO()
+        with self.assertRaisesMessage(RuntimeError, 'Max post-process passes exceeded'):
+            call_command('collectstatic', interactive=False, verbosity=0, stderr=err)
+        self.assertEqual("Post-processing 'All' failed!\n\n", err.getvalue())
+        self.assertPostCondition()
 
     def test_post_processing(self):
         """
@@ -173,14 +207,16 @@ class TestHashedFiles(object):
         self.assertIn(os.path.join('cached', 'css', 'window.css'), stats['post_processed'])
         self.assertIn(os.path.join('cached', 'css', 'img', 'window.png'), stats['unmodified'])
         self.assertIn(os.path.join('test', 'nonascii.css'), stats['post_processed'])
+        self.assertPostCondition()
 
     def test_css_import_case_insensitive(self):
         relpath = self.hashed_file_path("cached/styles_insensitive.css")
-        self.assertEqual(relpath, "cached/styles_insensitive.c609562b6d3c.css")
+        self.assertEqual(relpath, "cached/styles_insensitive.3fa427592a53.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
             content = relfile.read()
             self.assertNotIn(b"cached/other.css", content)
             self.assertIn(b"other.d41d8cd98f00.css", content)
+        self.assertPostCondition()
 
     @override_settings(
         STATICFILES_DIRS=[os.path.join(TEST_ROOT, 'project', 'faulty')],
@@ -195,6 +231,7 @@ class TestHashedFiles(object):
         with self.assertRaises(Exception):
             call_command('collectstatic', interactive=False, verbosity=0, stderr=err)
         self.assertEqual("Post-processing 'faulty.css' failed!\n\n", err.getvalue())
+        self.assertPostCondition()
 
 
 @override_settings(
@@ -206,7 +243,7 @@ class TestCollectionCachedStorage(TestHashedFiles, CollectionTestCase):
     """
     def test_cache_invalidation(self):
         name = "cached/styles.css"
-        hashed_name = "cached/styles.bb84a0240107.css"
+        hashed_name = "cached/styles.5e0040571e1a.css"
         # check if the cache is filled correctly as expected
         cache_key = storage.staticfiles_storage.hash_key(name)
         cached_name = storage.staticfiles_storage.hashed_files.get(cache_key)
@@ -219,6 +256,17 @@ class TestCollectionCachedStorage(TestHashedFiles, CollectionTestCase):
         cached_name = storage.staticfiles_storage.hashed_files.get(cache_key)
         self.assertEqual(cached_name, hashed_name)
 
+        # Check files that had to be hashed multiple times since their content
+        # includes other files that were hashed.
+        name = 'cached/relative.css'
+        hashed_name = 'cached/relative.c3e9e1ea6f2e.css'
+        cache_key = storage.staticfiles_storage.hash_key(name)
+        cached_name = storage.staticfiles_storage.hashed_files.get(cache_key)
+        self.assertIsNone(cached_name)
+        self.assertEqual(self.hashed_file_path(name), hashed_name)
+        cached_name = storage.staticfiles_storage.hashed_files.get(cache_key)
+        self.assertEqual(cached_name, hashed_name)
+
     def test_cache_key_memcache_validation(self):
         """
         Handle cache key creation correctly, see #17861.
@@ -236,6 +284,22 @@ class TestCollectionCachedStorage(TestHashedFiles, CollectionTestCase):
         cache_validator.validate_key(cache_key)
         self.assertEqual(cache_key, 'staticfiles:821ea71ef36f95b3922a77f7364670e7')
 
+    def test_corrupt_intermediate_files(self):
+        configured_storage = storage.staticfiles_storage
+        # Clear cache to force rehashing of the files
+        configured_storage.hashed_files.clear()
+        # Simulate a corrupt chain of intermediate files by ensuring they don't
+        # resolve before the max post-process count, which would normally be
+        # high enough.
+        configured_storage.max_post_process_passes = 1
+        # File without intermediates that can be rehashed without a problem.
+        self.hashed_file_path('cached/css/img/window.png')
+        # File with too many intermediates to rehash with the low max
+        # post-process passes.
+        err_msg = "The name 'cached/styles.css' could not be hashed with %r." % (configured_storage._wrapped,)
+        with self.assertRaisesMessage(ValueError, err_msg):
+            self.hashed_file_path('cached/styles.css')
+
 
 @override_settings(
     STATICFILES_STORAGE='staticfiles_tests.storage.ExtraPatternsCachedStaticFilesStorage',
@@ -258,15 +322,15 @@ class TestExtraPatternsCachedStorage(CollectionTestCase):
         """
         # CSS files shouldn't be touched by JS patterns.
         relpath = self.cached_file_path("cached/import.css")
-        self.assertEqual(relpath, "cached/import.2b1d40b0bbd4.css")
+        self.assertEqual(relpath, "cached/import.f53576679e5a.css")
         with storage.staticfiles_storage.open(relpath) as relfile:
-            self.assertIn(b'import url("styles.bb84a0240107.css")', relfile.read())
+            self.assertIn(b'import url("styles.5e0040571e1a.css")', relfile.read())
 
         # Confirm JS patterns have been applied to JS files.
         relpath = self.cached_file_path("cached/test.js")
-        self.assertEqual(relpath, "cached/test.62789ffcd280.js")
+        self.assertEqual(relpath, "cached/test.388d7a790d46.js")
         with storage.staticfiles_storage.open(relpath) as relfile:
-            self.assertIn(b'JS_URL("import.2b1d40b0bbd4.css")', relfile.read())
+            self.assertIn(b'JS_URL("import.f53576679e5a.css")', relfile.read())
 
 
 @override_settings(
@@ -289,6 +353,7 @@ class TestCollectionManifestStorage(TestHashedFiles, CollectionTestCase):
             STATICFILES_DIRS=settings.STATICFILES_DIRS + [temp_dir])
         self.patched_settings.enable()
         self.addCleanup(shutil.rmtree, six.text_type(temp_dir))
+        self._manifest_strict = storage.staticfiles_storage.manifest_strict
 
     def tearDown(self):
         self.patched_settings.disable()
@@ -296,8 +361,17 @@ class TestCollectionManifestStorage(TestHashedFiles, CollectionTestCase):
         if os.path.exists(self._clear_filename):
             os.unlink(self._clear_filename)
 
+        storage.staticfiles_storage.manifest_strict = self._manifest_strict
         super(TestCollectionManifestStorage, self).tearDown()
 
+    def assertPostCondition(self):
+        hashed_files = storage.staticfiles_storage.hashed_files
+        # The in-memory version of the manifest matches the one on disk
+        # since a properly created manifest should cover all filenames.
+        if hashed_files:
+            manifest = storage.staticfiles_storage.load_manifest()
+            self.assertEqual(hashed_files, manifest)
+
     def test_manifest_exists(self):
         filename = storage.staticfiles_storage.manifest_name
         path = storage.staticfiles_storage.path(filename)
@@ -317,7 +391,7 @@ class TestCollectionManifestStorage(TestHashedFiles, CollectionTestCase):
         self.assertEqual(hashed_files, manifest)
 
     def test_clear_empties_manifest(self):
-        cleared_file_name = os.path.join('test', 'cleared.txt')
+        cleared_file_name = storage.staticfiles_storage.clean_name(os.path.join('test', 'cleared.txt'))
         # collect the additional file
         self.run_collectstatic()
 
@@ -342,6 +416,27 @@ class TestCollectionManifestStorage(TestHashedFiles, CollectionTestCase):
         manifest_content = storage.staticfiles_storage.load_manifest()
         self.assertNotIn(cleared_file_name, manifest_content)
 
+    def test_missing_entry(self):
+        missing_file_name = 'cached/missing.css'
+        configured_storage = storage.staticfiles_storage
+        self.assertNotIn(missing_file_name, configured_storage.hashed_files)
+
+        # File name not found in manifest
+        with self.assertRaisesMessage(ValueError, "Missing staticfiles manifest entry for '%s'" % missing_file_name):
+            self.hashed_file_path(missing_file_name)
+
+        configured_storage.manifest_strict = False
+        # File doesn't exist on disk
+        err_msg = "The file '%s' could not be found with %r." % (missing_file_name, configured_storage._wrapped)
+        with self.assertRaisesMessage(ValueError, err_msg):
+            self.hashed_file_path(missing_file_name)
+
+        content = six.StringIO()
+        content.write('Found')
+        configured_storage.save(missing_file_name, content)
+        # File exists on disk
+        self.hashed_file_path(missing_file_name)
+
 
 @override_settings(
     STATICFILES_STORAGE='staticfiles_tests.storage.SimpleCachedStaticFilesStorage',
@@ -446,3 +541,45 @@ class TestStaticFilePermissions(CollectionTestCase):
         dir_mode = os.stat(test_dir)[0] & 0o777
         self.assertEqual(file_mode, 0o640)
         self.assertEqual(dir_mode, 0o740)
+
+
+@override_settings(
+    STATICFILES_STORAGE='django.contrib.staticfiles.storage.CachedStaticFilesStorage',
+)
+class TestCollectionHashedFilesCache(CollectionTestCase):
+    """
+    Files referenced from CSS use the correct final hashed name regardless of
+    the order in which the files are post-processed.
+    """
+    hashed_file_path = hashed_file_path
+
+    def setUp(self):
+        self.testimage_path = os.path.join(
+            TEST_ROOT, 'project', 'documents', 'cached', 'css', 'img', 'window.png'
+        )
+        with open(self.testimage_path, 'r+b') as f:
+            self._orig_image_content = f.read()
+        super(TestCollectionHashedFilesCache, self).setUp()
+
+    def tearDown(self):
+        with open(self.testimage_path, 'w+b') as f:
+            f.write(self._orig_image_content)
+        super(TestCollectionHashedFilesCache, self).tearDown()
+
+    def test_file_change_after_collectstatic(self):
+        finders.get_finder.cache_clear()
+        err = six.StringIO()
+        call_command('collectstatic', interactive=False, verbosity=0, stderr=err)
+        with open(self.testimage_path, 'w+b') as f:
+            f.write(b"new content of png file to change it's hash")
+
+        # Change modification time of self.testimage_path to make sure it gets
+        # collected again.
+        mtime = os.path.getmtime(self.testimage_path)
+        atime = os.path.getatime(self.testimage_path)
+        os.utime(self.testimage_path, (mtime + 1, atime + 1))
+
+        call_command('collectstatic', interactive=False, verbosity=0, stderr=err)
+        relpath = self.hashed_file_path('cached/css/window.css')
+        with storage.staticfiles_storage.open(relpath) as relfile:
+            self.assertIn(b'window.a836fe39729e.png', relfile.read())