Using already cloned repos as a reference, if the reference is not provided by the user

Author: mikicz

arca/_arca.py

@@ -249,6 +249,35 @@ def pull_again(self, repo: Optional[str]=None, branch: Optional[str]=None) -> No
             except KeyError:
                 pass
 
+    def get_reference_repository(self, reference: Optional[Path], repo: str) -> Optional[Path]:
+        """
+        Returns a repository to use in clone command, if there is one to be referenced.
+        Either provided by the user of generated from already cloned branches (master is preferred).
+
+        :param reference: Path to a local repository provided by the user or None.
+        :param repo: Reference for which remote repository.
+        """
+        if reference is not None:
+            return reference.absolute()
+
+        repo_path = self.get_path_to_repo(repo)
+
+        if not repo_path.exists():
+            return None
+
+        master = repo_path / "master"
+
+        if master.exists() and master.is_dir():
+            return master
+
+        for existing_branch in repo_path.iterdir():
+            if not existing_branch.is_dir():
+                continue
+
+            return existing_branch.resolve()
+
+        return None
+
     def _pull(self, *, repo_path: Path=None, git_repo: Repo=None, repo: str=None, branch: str=None,
               depth: Optional[int]=None,
               reference: Optional[Path]=None
@@ -271,8 +300,10 @@ def _pull(self, *, repo_path: Path=None, git_repo: Repo=None, repo: str=None, br
             if depth is not None:
                 kwargs["depth"] = depth
 
+            reference = self.get_reference_repository(reference, repo)
+
             if reference is not None:
-                kwargs["reference-if-able"] = str(reference.absolute())
+                kwargs["reference-if-able"] = str(reference)
                 kwargs["dissociate"] = True
 
             try:

tests/test_arca_class.py

@@ -307,6 +307,30 @@ def test_reference_validate(temp_repo_static, reference, valid):
             arca.static_filename(temp_repo_static.url, temp_repo_static.branch, relative_path, reference=reference)
 
 
+def test_get_reference_repository(temp_repo_static):
+    """
+    Test that the :meth:`Arca.get_reference_repository` works when reference is not provided by the user
+    or when branch `master` is not pulled first (as it is in other tests).
+    """
+    temp_repo_static.file_path.write_text("master")
+    temp_repo_static.repo.index.add([str(temp_repo_static.file_path)])
+    temp_repo_static.repo.index.commit("Initial")
+
+    for branch in "branch1", "branch2", "branch3":
+        temp_repo_static.repo.create_head(branch)
+        temp_repo_static.repo.branches[branch].checkout()
+        temp_repo_static.file_path.write_text(branch)
+        temp_repo_static.repo.index.add([str(temp_repo_static.file_path)])
+        temp_repo_static.repo.index.commit(branch)
+
+    arca = Arca(base_dir=BASE_DIR)
+
+    for branch in "branch1", "branch2", "master", "branch3":
+        _, path = arca.get_files(temp_repo_static.url, branch)
+
+        assert (path / temp_repo_static.file_path.name).read_text() == branch
+
+
 def test_pull_error():
     arca = Arca(base_dir=BASE_DIR)