Revert "Add handling for no ref being provided"

repo2docker/app.py

@@ -144,13 +144,10 @@ class Repo2Docker(Application):
         # create a shallow clone first
         _clone(depth=50)
 
-        # ref == None means we want to use HEAD so no need to checkout a
-        # specific revision
-        if ref is not None:
-            if not _contains(ref):
-                # have to create a full clone
-                _unshallow()
-            _checkout(ref)
+        if not _contains(ref):
+            # have to create a full clone
+            _unshallow()
+        _checkout(ref)
 
     def get_argparser(self):
         argparser = argparse.ArgumentParser()

tests/conftest.py

@@ -51,8 +51,9 @@ class RemoteRepoTest(pytest.Item):
         self.verify = verify
 
     def runtest(self):
-        if self.ref is not None:
-            cmd = ['jupyter-repo2docker', '--ref', self.ref, self.url, '--']
-        else:
-            cmd = ['jupyter-repo2docker', self.url, '--']
-        subprocess.check_call(cmd + shlex.split(self.verify))
+        subprocess.check_call([
+            'jupyter-repo2docker',
+            '--ref', self.ref,
+            self.url,
+            '--',
+        ] + shlex.split(self.verify))

tests/external/shallow-clone.repos.yaml

@@ -11,9 +11,3 @@
   # we checkout the second to last commit, hence the log has 49 entries at a
   # max clone depth of 50
   verify: /bin/bash -c '[ $(git log --oneline | wc -l) == "49" ]'
-
-- name: A dummy repo with 100 commits - live at HEAD
-  url: https://github.com/betatim/repo2docker-ci-clone-depth
-  # provide no ref, aka use HEAD, aka the 100th commit
-  ref: NULL
-  verify: python -c "commit = open('COMMIT').read(); assert int(commit) == 100, 'this is not the 100th commit'"