Remove support for COMPREHENSIVE_THEME_DIR -

  all dirs must now go into COMPREHENSIVE_THEME_DIRS.
Move comprehensive theming setup section out of startup.py and into
  settings files using new 'derived' functionality.
Add 'derive_settings' at the end of all top-level Django settings files.
Move validation of comprehensive theming settings into new apps.py
  theming file.
Split theming code into code safe to run before settings are initialized
  -and- after settings are initialized.

cms/envs/aws.py

@@ -15,6 +15,7 @@ import json
 
 from .common import *
 
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 import os
 
@@ -202,10 +203,6 @@ COURSES_WITH_UNSAFE_CODE = ENV_TOKENS.get("COURSES_WITH_UNSAFE_CODE", [])
 
 ASSET_IGNORE_REGEX = ENV_TOKENS.get('ASSET_IGNORE_REGEX', ASSET_IGNORE_REGEX)
 
-# following setting is for backward compatibility
-if ENV_TOKENS.get('COMPREHENSIVE_THEME_DIR', None):
-    COMPREHENSIVE_THEME_DIR = ENV_TOKENS.get('COMPREHENSIVE_THEME_DIR')
-
 COMPREHENSIVE_THEME_DIRS = ENV_TOKENS.get('COMPREHENSIVE_THEME_DIRS', COMPREHENSIVE_THEME_DIRS) or []
 
 # COMPREHENSIVE_THEME_LOCALE_PATHS contain the paths to themes locale directories e.g.
@@ -534,3 +531,7 @@ PARENTAL_CONSENT_AGE_LIMIT = ENV_TOKENS.get(
 
 # Allow extra middleware classes to be added to the app through configuration.
 MIDDLEWARE_CLASSES.extend(ENV_TOKENS.get('EXTRA_MIDDLEWARE_CLASSES', []))
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

cms/envs/common.py

@@ -50,7 +50,7 @@ import lms.envs.common
 from lms.envs.common import (
     USE_TZ, TECH_SUPPORT_EMAIL, PLATFORM_NAME, PLATFORM_DESCRIPTION, BUGS_EMAIL, DOC_STORE_CONFIG, DATA_DIR,
     ALL_LANGUAGES, WIKI_ENABLED, update_module_store_settings, ASSET_IGNORE_REGEX,
-    PARENTAL_CONSENT_AGE_LIMIT, COMPREHENSIVE_THEME_DIRS, REGISTRATION_EMAIL_PATTERNS_ALLOWED,
+    PARENTAL_CONSENT_AGE_LIMIT, REGISTRATION_EMAIL_PATTERNS_ALLOWED,
     # The following PROFILE_IMAGE_* settings are included as they are
     # indirectly accessed through the email opt-in API, which is
     # technically accessible through the CMS via legacy URLs.
@@ -81,6 +81,8 @@ from lms.envs.common import (
 
     # Enable or disable theming
     ENABLE_COMPREHENSIVE_THEMING,
+    COMPREHENSIVE_THEME_LOCALE_PATHS,
+    COMPREHENSIVE_THEME_DIRS,
 
     # constants for redirects app
     REDIRECT_CACHE_TIMEOUT,
@@ -113,6 +115,10 @@ from lms.envs.common import (
     # Video Image settings
     VIDEO_IMAGE_SETTINGS,
     VIDEO_TRANSCRIPTS_SETTINGS,
+
+    # Methods to derive settings
+    _make_main_mako_templates,
+    _make_locale_paths,
 )
 from path import Path as path
 from warnings import simplefilter
@@ -121,7 +127,12 @@ from lms.djangoapps.lms_xblock.mixin import LmsBlockMixin
 from cms.lib.xblock.authoring_mixin import AuthoringMixin
 import dealer.git
 from xmodule.modulestore.edit_info import EditInfoMixin
+from openedx.core.djangoapps.theming.helpers_dirs import (
+    get_themes_unchecked,
+    get_theme_base_dirs_from_settings
+)
 from openedx.core.lib.license import LicenseMixin
+from openedx.core.lib.derived import derived, derived_dict_entry
 
 ############################ FEATURE CONFIGURATION #############################
 
@@ -300,7 +311,7 @@ GEOIPV6_PATH = REPO_ROOT / "common/static/data/geoip/GeoIPv6.dat"
 import tempfile
 MAKO_MODULE_DIR = os.path.join(tempfile.gettempdir(), 'mako_cms')
 MAKO_TEMPLATES = {}
-MAKO_TEMPLATES['main'] = [
+MAIN_MAKO_TEMPLATES_BASE = [
     PROJECT_ROOT / 'templates',
     COMMON_ROOT / 'templates',
     COMMON_ROOT / 'djangoapps' / 'pipeline_mako' / 'templates',
@@ -310,9 +321,10 @@ MAKO_TEMPLATES['main'] = [
     OPENEDX_ROOT / 'core' / 'lib' / 'license' / 'templates',
     CMS_ROOT / 'djangoapps' / 'pipeline_js' / 'templates',
 ]
+MAKO_TEMPLATES['lms.main'] = lms.envs.common.MAIN_MAKO_TEMPLATES_BASE
 
-for namespace, template_dirs in lms.envs.common.MAKO_TEMPLATES.iteritems():
-    MAKO_TEMPLATES['lms.' + namespace] = template_dirs
+MAKO_TEMPLATES['main'] = _make_main_mako_templates
+derived_dict_entry('MAKO_TEMPLATES', 'main')
 
 # Django templating
 TEMPLATES = [
@@ -321,7 +333,7 @@ TEMPLATES = [
         # Don't look for template source files inside installed applications.
         'APP_DIRS': False,
         # Instead, look for template source files in these dirs.
-        'DIRS': MAKO_TEMPLATES['main'],
+        'DIRS': MAIN_MAKO_TEMPLATES_BASE,
         # Options specific to this backend.
         'OPTIONS': {
             'loaders': (
@@ -601,8 +613,9 @@ USE_L10N = True
 
 STATICI18N_ROOT = PROJECT_ROOT / "static"
 
-# Localization strings (e.g. django.po) are under this directory
-LOCALE_PATHS = (REPO_ROOT + '/conf/locale',)  # edx-platform/conf/locale/
+# Localization strings (e.g. django.po) are under these directories
+LOCALE_PATHS = _make_locale_paths
+derived('LOCALE_PATHS')
 
 # Messages
 MESSAGE_STORAGE = 'django.contrib.messages.storage.session.SessionStorage'
@@ -959,7 +972,7 @@ INSTALLED_APPS = [
     'webpack_loader',
 
     # Theming
-    'openedx.core.djangoapps.theming',
+    'openedx.core.djangoapps.theming.apps.ThemingConfig',
 
     # Site configuration for theming and behavioral modification
     'openedx.core.djangoapps.site_configuration',
@@ -1370,9 +1383,6 @@ AFFILIATE_COOKIE_NAME = 'affiliate_id'
 
 HELP_TOKENS_INI_FILE = REPO_ROOT / "cms" / "envs" / "help_tokens.ini"
 
-# Theme directory locale paths
-COMPREHENSIVE_THEME_LOCALE_PATHS = []
-
 # This is required for the migrations in oauth_dispatch.models
 # otherwise it fails saying this attribute is not present in Settings
 # Although Studio does not exable OAuth2 Provider capability, the new approach

cms/envs/dev.py

@@ -6,6 +6,7 @@ This config file runs the simplest dev environment"""
 # pylint: disable=wildcard-import, unused-wildcard-import
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 
 # import settings from LMS for consistent behavior with CMS
@@ -179,3 +180,7 @@ try:
     from .private import *  # pylint: disable=import-error
 except ImportError:
     pass
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

cms/envs/test.py

@@ -24,6 +24,7 @@ from path import Path as path
 from warnings import filterwarnings, simplefilter
 from uuid import uuid4
 from util.db import NoOpMigrationModules
+from openedx.core.lib.derived import derive_settings
 
 # import settings from LMS for consistent behavior with CMS
 # pylint: disable=unused-import
@@ -360,3 +361,7 @@ VIDEO_TRANSCRIPTS_SETTINGS = dict(
     ),
     DIRECTORY_PREFIX='video-transcripts/',
 )
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

cms/envs/test_static_optimized.py

@@ -12,6 +12,7 @@ from the same directory.
 
 # Start with the common settings
 from .common import *  # pylint: disable=wildcard-import, unused-wildcard-import
+from openedx.core.lib.derived import derive_settings
 
 # Use an in-memory database since this settings file is only used for updating assets
 DATABASES = {
@@ -46,3 +47,7 @@ WEBPACK_LOADER['DEFAULT']['STATS_FILE'] = STATIC_ROOT / "webpack-stats.json"
 # 1. Uglify is by far the slowest part of the build process
 # 2. Having full source code makes debugging tests easier for developers
 os.environ['REQUIRE_BUILD_PROFILE_OPTIMIZE'] = 'none'
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

cms/envs/yaml_config.py

@@ -17,6 +17,7 @@ defined in the environment:
 import yaml
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 from util.config_parse import convert_tokens
 import os
@@ -264,3 +265,7 @@ if FEATURES.get('CUSTOM_COURSES_EDX'):
 
 # Allow extra middleware classes to be added to the app through configuration.
 MIDDLEWARE_CLASSES.extend(ENV_TOKENS.get('EXTRA_MIDDLEWARE_CLASSES', []))
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

cms/startup.py

@@ -8,17 +8,16 @@ from django.conf import settings
 import cms.lib.xblock.runtime
 import xmodule.x_module
 from openedx.core.djangoapps.monkey_patch import django_db_models_options
-from openedx.core.djangoapps.theming.core import enable_theming
-from openedx.core.djangoapps.theming.helpers import is_comprehensive_theming_enabled
 from openedx.core.lib.django_startup import autostartup
-from openedx.core.lib.xblock_utils import xblock_local_resource_url
-from openedx.core.release import doc_version
-from startup_configurations.validate_config import validate_cms_config
 
 # Force settings to run so that the python path is modified
 
 settings.INSTALLED_APPS  # pylint: disable=pointless-statement
 
+from openedx.core.lib.xblock_utils import xblock_local_resource_url
+from openedx.core.release import doc_version
+from startup_configurations.validate_config import validate_cms_config
+
 
 def run():
     """
@@ -29,11 +28,6 @@ def run():
     """
     django_db_models_options.patch()
 
-    # Comprehensive theming needs to be set up before django startup,
-    # because modifying django template paths after startup has no effect.
-    if is_comprehensive_theming_enabled():
-        enable_theming()
-
     django.setup()
 
     autostartup()

lms/envs/aws.py

@@ -25,6 +25,7 @@ import warnings
 import dateutil
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 import os
 
@@ -1068,3 +1069,7 @@ ACE_ROUTING_KEY = ENV_TOKENS.get('ACE_ROUTING_KEY', ACE_ROUTING_KEY)
 
 # Allow extra middleware classes to be added to the app through configuration.
 MIDDLEWARE_CLASSES.extend(ENV_TOKENS.get('EXTRA_MIDDLEWARE_CLASSES', []))
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/envs/common.py

@@ -39,9 +39,13 @@ from warnings import simplefilter
 from django.utils.translation import ugettext_lazy as _
 
 from .discussionsettings import *
+from openedx.core.djangoapps.theming.helpers_dirs import (
+    get_themes_unchecked,
+    get_theme_base_dirs_from_settings
+)
+from openedx.core.lib.derived import derived, derived_dict_entry
 from xmodule.modulestore.modulestore_settings import update_module_store_settings
 from xmodule.modulestore.edit_info import EditInfoMixin
-from openedx.core.lib.license import LicenseMixin
 from lms.djangoapps.lms_xblock.mixin import LmsBlockMixin
 
 ################################### FEATURES ###################################
@@ -530,7 +534,7 @@ OAUTH2_PROVIDER_APPLICATION_MODEL = 'oauth2_provider.Application'
 import tempfile
 MAKO_MODULE_DIR = os.path.join(tempfile.gettempdir(), 'mako_lms')
 MAKO_TEMPLATES = {}
-MAKO_TEMPLATES['main'] = [
+MAIN_MAKO_TEMPLATES_BASE = [
     PROJECT_ROOT / 'templates',
     COMMON_ROOT / 'templates',
     COMMON_ROOT / 'lib' / 'capa' / 'capa' / 'templates',
@@ -540,6 +544,20 @@ MAKO_TEMPLATES['main'] = [
     OPENEDX_ROOT / 'core' / 'lib' / 'license' / 'templates',
 ]
 
+
+def _make_main_mako_templates(settings):
+    """
+    Derives the final MAKO_TEMPLATES['main'] setting from other settings.
+    """
+    if settings.ENABLE_COMPREHENSIVE_THEMING:
+        themes_dirs = get_theme_base_dirs_from_settings(settings.COMPREHENSIVE_THEME_DIRS)
+        for theme in get_themes_unchecked(themes_dirs, PROJECT_ROOT):
+            if theme.themes_base_dir not in settings.MAIN_MAKO_TEMPLATES_BASE:
+                settings.MAIN_MAKO_TEMPLATES_BASE.insert(0, theme.themes_base_dir)
+    return settings.MAIN_MAKO_TEMPLATES_BASE
+MAKO_TEMPLATES['main'] = _make_main_mako_templates
+derived_dict_entry('MAKO_TEMPLATES', 'main')
+
 # Django templating
 TEMPLATES = [
     {
@@ -1015,8 +1033,18 @@ USE_L10N = True
 STATICI18N_ROOT = PROJECT_ROOT / "static"
 STATICI18N_OUTPUT_DIR = "js/i18n"
 
-# Localization strings (e.g. django.po) are under this directory
-LOCALE_PATHS = (REPO_ROOT + '/conf/locale',)  # edx-platform/conf/locale/
+
+# Localization strings (e.g. django.po) are under these directories
+def _make_locale_paths(settings):
+    locale_paths = [settings.REPO_ROOT + '/conf/locale']  # edx-platform/conf/locale/
+    if settings.ENABLE_COMPREHENSIVE_THEMING:
+        # Add locale paths to settings for comprehensive theming.
+        for locale_path in settings.COMPREHENSIVE_THEME_LOCALE_PATHS:
+            locale_paths += (path(locale_path), )
+    return locale_paths
+LOCALE_PATHS = _make_locale_paths
+derived('LOCALE_PATHS')
+
 # Messages
 MESSAGE_STORAGE = 'django.contrib.messages.storage.session.SessionStorage'
 
@@ -2018,7 +2046,7 @@ INSTALLED_APPS = [
     'openedx.core.djangoapps.contentserver',
 
     # Theming
-    'openedx.core.djangoapps.theming',
+    'openedx.core.djangoapps.theming.apps.ThemingConfig',
 
     # Site configuration for theming and behavioral modification
     'openedx.core.djangoapps.site_configuration',

lms/envs/dev.py

@@ -13,6 +13,7 @@ sessions. Assumes structure:
 # pylint: disable=wildcard-import, unused-wildcard-import
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 
 DEBUG = True
 TEMPLATE_DEBUG = True
@@ -270,3 +271,7 @@ try:
     from .private import *      # pylint: disable=import-error
 except ImportError:
     pass
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/envs/static.py

@@ -13,6 +13,7 @@ sessions. Assumes structure:
 # pylint: disable=wildcard-import, unused-wildcard-import
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 
 STATIC_GRAB = True
@@ -69,3 +70,7 @@ FILE_UPLOAD_HANDLERS = [
     'django.core.files.uploadhandler.MemoryFileUploadHandler',
     'django.core.files.uploadhandler.TemporaryFileUploadHandler',
 ]
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/envs/test.py

@@ -25,6 +25,7 @@ from uuid import uuid4
 from warnings import filterwarnings, simplefilter
 
 from util.db import NoOpMigrationModules
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.tempdir import mkdtemp_clean
 
 # This patch disables the commit_on_success decorator during tests
@@ -506,7 +507,7 @@ MICROSITE_LOGISTRATION_HOSTNAME = 'logistration.testserver'
 TEST_THEME = COMMON_ROOT / "test" / "test-theme"
 
 # add extra template directory for test-only templates
-MAKO_TEMPLATES['main'].extend([
+MAIN_MAKO_TEMPLATES_BASE.extend([
     COMMON_ROOT / 'test' / 'templates',
     COMMON_ROOT / 'test' / 'test_sites',
     REPO_ROOT / 'openedx' / 'core' / 'djangolib' / 'tests' / 'templates',
@@ -605,3 +606,7 @@ ENTERPRISE_CONSENT_API_URL = 'http://enterprise.example.com/consent/api/v1/'
 ACTIVATION_EMAIL_FROM_ADDRESS = 'test_activate@edx.org'
 
 TEMPLATES[0]['OPTIONS']['debug'] = True
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/envs/test_static_optimized.py

@@ -12,6 +12,7 @@ from the same directory.
 
 # Start with the common settings
 from .common import *  # pylint: disable=wildcard-import, unused-wildcard-import
+from openedx.core.lib.derived import derive_settings
 
 # Use an in-memory database since this settings file is only used for updating assets
 DATABASES = {
@@ -59,3 +60,7 @@ WEBPACK_LOADER['DEFAULT']['STATS_FILE'] = STATIC_ROOT / "webpack-stats.json"
 # 1. Uglify is by far the slowest part of the build process
 # 2. Having full source code makes debugging tests easier for developers
 os.environ['REQUIRE_BUILD_PROFILE_OPTIMIZE'] = 'none'
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/envs/yaml_config.py

@@ -16,6 +16,7 @@ defined in the environment:
 import yaml
 
 from .common import *
+from openedx.core.lib.derived import derive_settings
 from openedx.core.lib.logsettings import get_logger_config
 from util.config_parse import convert_tokens
 import os
@@ -329,3 +330,7 @@ CREDENTIALS_GENERATION_ROUTING_KEY = HIGH_PRIORITY_QUEUE
 
 # Allow extra middleware classes to be added to the app through configuration.
 MIDDLEWARE_CLASSES.extend(ENV_TOKENS.get('EXTRA_MIDDLEWARE_CLASSES', []))
+
+########################## Derive Any Derived Settings  #######################
+
+derive_settings(__name__)

lms/startup.py

@@ -21,8 +21,6 @@ import xmodule.x_module
 import lms_xblock.runtime
 
 from startup_configurations.validate_config import validate_lms_config
-from openedx.core.djangoapps.theming.core import enable_theming
-from openedx.core.djangoapps.theming.helpers import is_comprehensive_theming_enabled
 
 from microsite_configuration import microsite
 
@@ -38,11 +36,6 @@ def run():
     """
     django_db_models_options.patch()
 
-    # Comprehensive theming needs to be set up before django startup,
-    # because modifying django template paths after startup has no effect.
-    if is_comprehensive_theming_enabled():
-        enable_theming()
-
     # We currently use 2 template rendering engines, mako and django_templates,
     # and one of them (django templates), requires the directories be added
     # before the django.setup().

openedx/core/djangoapps/theming/apps.py

+
+import os
+import six
+from django.apps import AppConfig
+from django.conf import settings
+from django.core.checks import Error, Tags, register
+
+
+class ThemingConfig(AppConfig):
+    name = 'openedx.core.djangoapps.theming'
+    verbose_name = "Theming"
+
+
+@register(Tags.compatibility)
+def check_comprehensive_theme_settings(app_configs, **kwargs):
+    """
+    Checks the comprehensive theming theme directory settings.
+
+    Raises compatibility Errors upon:
+        - COMPREHENSIVE_THEME_DIRS is not a list
+        - theme dir path is not a string
+        - theme dir path is not an absolute path
+        - path specified in COMPREHENSIVE_THEME_DIRS does not exist
+
+    Returns:
+        List of any Errors.
+    """
+    if not getattr(settings, "ENABLE_COMPREHENSIVE_THEMING"):
+        # Only perform checks when comprehensive theming is enabled.
+        return []
+
+    errors = []
+
+    # COMPREHENSIVE_THEME_DIR is no longer supported - support has been removed.
+    if hasattr(settings, "COMPREHENSIVE_THEME_DIR"):
+        theme_dir = settings.COMPREHENSIVE_THEME_DIR
+
+        errors.append(
+            Error(
+                "COMPREHENSIVE_THEME_DIR setting has been removed in favor of COMPREHENSIVE_THEME_DIRS.",
+                hint='Transfer the COMPREHENSIVE_THEME_DIR value to COMPREHENSIVE_THEME_DIRS.',
+                obj=theme_dir,
+                id='openedx.core.djangoapps.theming.E001',
+            )
+        )
+
+    if hasattr(settings, "COMPREHENSIVE_THEME_DIRS"):
+        theme_dirs = settings.COMPREHENSIVE_THEME_DIRS
+
+        if not isinstance(theme_dirs, list):
+            errors.append(
+                Error(
+                    "COMPREHENSIVE_THEME_DIRS must be a list.",
+                    obj=theme_dirs,
+                    id='openedx.core.djangoapps.theming.E004',
+                )
+            )
+        if not all([isinstance(theme_dir, six.string_types) for theme_dir in theme_dirs]):
+            errors.append(
+                Error(
+                    "COMPREHENSIVE_THEME_DIRS must contain only strings.",
+                    obj=theme_dirs,
+                    id='openedx.core.djangoapps.theming.E005',
+                )
+            )
+        if not all([theme_dir.startswith("/") for theme_dir in theme_dirs]):
+            errors.append(
+                Error(
+                    "COMPREHENSIVE_THEME_DIRS must contain only absolute paths to themes dirs.",
+                    obj=theme_dirs,
+                    id='openedx.core.djangoapps.theming.E006',
+                )
+            )
+        if not all([os.path.isdir(theme_dir) for theme_dir in theme_dirs]):
+            errors.append(
+                Error(
+                    "COMPREHENSIVE_THEME_DIRS must contain valid paths.",
+                    obj=theme_dirs,
+                    id='openedx.core.djangoapps.theming.E007',
+                )
+            )
+
+    return errors

openedx/core/djangoapps/theming/core.py

-"""
-Core logic for Comprehensive Theming.
-"""
-from logging import getLogger
-
-from django.conf import settings
-from path import Path as path
-
-from .helpers import get_themes
-
-logger = getLogger(__name__)  # pylint: disable=invalid-name
-
-
-def enable_theming():
-    """
-    Add directories and relevant paths to settings for comprehensive theming.
-    """
-    # Deprecated Warnings
-    if hasattr(settings, "COMPREHENSIVE_THEME_DIR"):
-        logger.warning(
-            "\033[93m \nDeprecated: "
-            "\n\tCOMPREHENSIVE_THEME_DIR setting has been deprecated in favor of COMPREHENSIVE_THEME_DIRS.\033[00m"
-        )
-
-    for theme in get_themes():
-        if theme.themes_base_dir not in settings.MAKO_TEMPLATES['main']:
-            settings.MAKO_TEMPLATES['main'].insert(0, theme.themes_base_dir)
-
-    _add_theming_locales()
-
-
-def _add_theming_locales():
-    """
-    Add locale paths to settings for comprehensive theming.
-    """
-    theme_locale_paths = settings.COMPREHENSIVE_THEME_LOCALE_PATHS
-    for locale_path in theme_locale_paths:
-        settings.LOCALE_PATHS += (path(locale_path), )  # pylint: disable=no-member

openedx/core/djangoapps/theming/helpers_dirs.py

+"""
+Code which dynamically discovers comprehensive themes. Deliberately uses no Django settings,
+as the discovery happens during the initial setup of Django settings.
+"""
+import os
+from path import Path
+
+
+def get_theme_base_dirs_from_settings(theme_dirs=None):
+    """
+    Return base directories that contains all the themes.
+
+    Example:
+        >> get_theme_base_dirs_from_settings('/edx/app/ecommerce/ecommerce/themes')
+        ['/edx/app/ecommerce/ecommerce/themes']
+
+    Returns:
+         (List of Paths): Base theme directory paths
+    """
+    theme_base_dirs = []
+    if theme_dirs:
+        theme_base_dirs.extend([Path(theme_dir) for theme_dir in theme_dirs])
+    return theme_base_dirs
+
+
+def get_themes_unchecked(themes_dirs, project_root=None):
+    """
+    Returns a list of all themes known to the system.
+
+    Args:
+        themes_dirs (list): Paths to themes base directory
+        project_root (str): (optional) Path to project root
+    Returns:
+        List of themes known to the system.
+    """
+    themes_base_dirs = [Path(themes_dir) for themes_dir in themes_dirs]
+    # pick only directories and discard files in themes directory
+    themes = []
+    for themes_dir in themes_base_dirs:
+        themes.extend([Theme(name, name, themes_dir, project_root) for name in get_theme_dirs(themes_dir)])
+
+    return themes
+
+
+def get_theme_dirs(themes_dir=None):
+    """
+    Returns theme dirs in given dirs
+    Args:
+        themes_dir (Path): base dir that contains themes.
+    """
+    return [_dir for _dir in os.listdir(themes_dir) if is_theme_dir(themes_dir / _dir)]
+
+
+def is_theme_dir(_dir):
+    """
+    Returns true if given dir contains theme overrides.
+    A theme dir must have subdirectory 'lms' or 'cms' or both.
+
+    Args:
+        _dir: directory path to check for a theme
+
+    Returns:
+        Returns true if given dir is a theme directory.
+    """
+    theme_sub_directories = {'lms', 'cms'}
+    return bool(os.path.isdir(_dir) and theme_sub_directories.intersection(os.listdir(_dir)))
+
+
+def get_project_root_name_from_settings(project_root):
+    """
+    Return root name for the current project
+
+    Example:
+        >> get_project_root_name()
+        'lms'
+        # from studio
+        >> get_project_root_name()
+        'cms'
+
+    Args:
+        project_root (str): Root directory of the project.
+
+    Returns:
+        (str): component name of platform e.g lms, cms
+    """
+    root = Path(project_root)
+    if root.name == "":
+        root = root.parent
+    return root.name
+
+
+class Theme(object):
+    """
+    class to encapsulate theme related information.
+    """
+    name = ''
+    theme_dir_name = ''
+    themes_base_dir = None
+    project_root = None
+
+    def __init__(self, name='', theme_dir_name='', themes_base_dir=None, project_root=None):
+        """
+        init method for Theme
+
+        Args:
+            name: name if the theme
+            theme_dir_name: directory name of the theme
+            themes_base_dir: directory path of the folder that contains the theme
+        """
+        self.name = name
+        self.theme_dir_name = theme_dir_name
+        self.themes_base_dir = themes_base_dir
+        self.project_root = project_root
+
+    def __eq__(self, other):
+        """
+        Returns True if given theme is same as the self
+        Args:
+            other: Theme object to compare with self
+
+        Returns:
+            (bool) True if two themes are the same else False
+        """
+        return (self.theme_dir_name, self.path) == (other.theme_dir_name, other.path)
+
+    def __hash__(self):
+        return hash((self.theme_dir_name, self.path))
+
+    def __unicode__(self):
+        return u"<Theme: {name} at '{path}'>".format(name=self.name, path=self.path)
+
+    def __repr__(self):
+        return self.__unicode__()
+
+    @property
+    def path(self):
+        """
+        Get absolute path of the directory that contains current theme's templates, static assets etc.
+
+        Returns:
+            Path: absolute path to current theme's contents
+        """
+        return Path(self.themes_base_dir) / self.theme_dir_name / get_project_root_name_from_settings(self.project_root)
+
+    @property
+    def template_path(self):
+        """
+        Get absolute path of current theme's template directory.
+
+        Returns:
+            Path: absolute path to current theme's template directory
+        """
+        return Path(self.theme_dir_name) / get_project_root_name_from_settings(self.project_root) / 'templates'
+
+    @property
+    def template_dirs(self):
+        """
+        Get a list of all template directories for current theme.
+
+        Returns:
+            list: list of all template directories for current theme.
+        """
+        return [
+            self.path / 'templates',
+        ]

openedx/core/djangoapps/theming/helpers_static.py

+
+from django.contrib.staticfiles.storage import staticfiles_storage
+
+
+def get_static_file_url(asset):
+    """
+    Returns url of the themed asset if asset is not themed than returns the default asset url.
+
+    Example:
+        >> get_static_file_url('css/lms-main-v1.css')
+        '/static/red-theme/css/lms-main-v1.css'
+
+    Parameters:
+        asset (str): asset's path relative to the static files directory
+
+    Returns:
+        (str): static asset's url
+    """
+    return staticfiles_storage.url(asset)

openedx/core/djangoapps/theming/management/commands/compile_sass.py

@@ -92,7 +92,7 @@ class Command(BaseCommand):
         if theme_dirs:
             available_themes = {}
             for theme_dir in theme_dirs:
-                available_themes.update({t.theme_dir_name: t for t in get_themes(theme_dir)})
+                available_themes.update({t.theme_dir_name: t for t in get_themes([theme_dir])})
         else:
             theme_dirs = get_theme_base_dirs()
             available_themes = {t.theme_dir_name: t for t in get_themes()}

openedx/core/djangoapps/theming/templatetags/theme_pipeline.py

@@ -9,7 +9,7 @@ from django.utils.safestring import mark_safe
 from pipeline.templatetags.pipeline import StylesheetNode, JavascriptNode
 from pipeline.utils import guess_type
 
-from openedx.core.djangoapps.theming.helpers import get_static_file_url
+from openedx.core.djangoapps.theming.helpers_static import get_static_file_url
 
 register = template.Library()  # pylint: disable=invalid-name
 

openedx/core/djangoapps/theming/tests/test_helpers.py

@@ -22,13 +22,13 @@ class TestHelpers(TestCase):
         Tests template paths are returned from enabled theme.
         """
         expected_themes = [
-            Theme('dark-theme', 'dark-theme', get_theme_base_dir('dark-theme')),
-            Theme('edge.edx.org', 'edge.edx.org', get_theme_base_dir('edge.edx.org')),
-            Theme('edx.org', 'edx.org', get_theme_base_dir('edx.org')),
-            Theme('open-edx', 'open-edx', get_theme_base_dir('open-edx')),
-            Theme('red-theme', 'red-theme', get_theme_base_dir('red-theme')),
-            Theme('stanford-style', 'stanford-style', get_theme_base_dir('stanford-style')),
-            Theme('test-theme', 'test-theme', get_theme_base_dir('test-theme')),
+            Theme('dark-theme', 'dark-theme', get_theme_base_dir('dark-theme'), settings.PROJECT_ROOT),
+            Theme('edge.edx.org', 'edge.edx.org', get_theme_base_dir('edge.edx.org'), settings.PROJECT_ROOT),
+            Theme('edx.org', 'edx.org', get_theme_base_dir('edx.org'), settings.PROJECT_ROOT),
+            Theme('open-edx', 'open-edx', get_theme_base_dir('open-edx'), settings.PROJECT_ROOT),
+            Theme('red-theme', 'red-theme', get_theme_base_dir('red-theme'), settings.PROJECT_ROOT),
+            Theme('stanford-style', 'stanford-style', get_theme_base_dir('stanford-style'), settings.PROJECT_ROOT),
+            Theme('test-theme', 'test-theme', get_theme_base_dir('test-theme'), settings.PROJECT_ROOT),
         ]
         actual_themes = get_themes()
         self.assertItemsEqual(expected_themes, actual_themes)
@@ -39,7 +39,7 @@ class TestHelpers(TestCase):
         Tests template paths are returned from enabled theme.
         """
         expected_themes = [
-            Theme('test-theme', 'test-theme', get_theme_base_dir('test-theme')),
+            Theme('test-theme', 'test-theme', get_theme_base_dir('test-theme'), settings.PROJECT_ROOT),
         ]
         actual_themes = get_themes()
         self.assertItemsEqual(expected_themes, actual_themes)