DEVOPS-776 fix: suppress pkg_resources deprecation warning from PyFilesystem (#13)

* DEVOPS-776 fix: suppress pkg_resources deprecation warning and replace fs.path with os.path in GitHubSource

* DEVOPS-776 fix: add assertion to ensure commit is not None in fetch method of GitHubSource

* DEVOPS-776 fix: raise RuntimeError if commit is None in fetch method of GitHubSource

Author: dipakparmar

cumulusci/__init__.py

@@ -1,7 +1,16 @@
 import os
 import sys
+import warnings
 from importlib.metadata import PackageNotFoundError, version
 
+# Suppress pkg_resources deprecation warning from PyFilesystem (fs) package
+# See: https://github.com/PyFilesystem/pyfilesystem2/issues/577
+warnings.filterwarnings(
+    "ignore",
+    message="pkg_resources is deprecated as an API",
+    category=UserWarning,
+)
+
 from simple_salesforce import api, bulk
 
 __location__ = os.path.dirname(os.path.realpath(__file__))

cumulusci/core/source/github.py

@@ -1,7 +1,6 @@
 import os
 import shutil
 
-import fs
 from github3.exceptions import NotFoundError
 
 from cumulusci.core.exceptions import DependencyResolutionError
@@ -128,8 +127,10 @@ def resolve(self):
 
     def fetch(self):
         """Fetch the archive of the specified commit and construct its project config."""
+        if self.commit is None:
+            raise RuntimeError("Cannot fetch: commit has not been resolved")
         with self.project_config.open_cache(
-            fs.path.join("projects", self.repo_name, self.commit)
+            os.path.join("projects", self.repo_name, self.commit)
         ) as path:
             zf = download_extract_github(
                 self.gh, self.repo_owner, self.repo_name, ref=self.commit