Merge pull request #3046 from Suor/clean-brancher

dvc: clean brancher

dvc/repo/brancher.py

@@ -5,12 +5,7 @@ from dvc.scm.tree import WorkingTree
 
 
 def brancher(  # noqa: E302
-    self,
-    branches=None,
-    all_branches=False,
-    tags=None,
-    all_tags=False,
-    all_commits=False,
+    self, all_branches=False, all_tags=False, all_commits=False
 ):
     """Generator that iterates over specified revisions.
 
@@ -26,7 +21,7 @@ def brancher(  # noqa: E302
             - empty string it there is no branches to iterate over
             - "Working Tree" if there are uncommitted changes in the SCM repo
     """
-    if not any([branches, all_branches, tags, all_tags, all_commits]):
+    if not any([all_branches, all_tags, all_commits]):
         yield ""
         return
 
@@ -42,24 +37,14 @@ def brancher(  # noqa: E302
         revs = scm.list_all_commits()
     else:
         if all_branches:
-            branches = scm.list_branches()
+            revs.extend(scm.list_branches())
 
         if all_tags:
-            tags = scm.list_tags()
+            revs.extend(scm.list_tags())
 
-        if branches is not None:
-            revs.extend(branches)
-
-        if tags is not None:
-            revs.extend(tags)
-
-    # NOTE: it might be a good idea to wrap this loop in try/finally block
-    # to don't leave the tree on some unexpected branch after the
-    # `brancher()`, but this could cause problems on exception handling
-    # code which might expect the tree on which exception was raised to
-    # stay in place. This behavior is a subject to change.
-    for sha, names in group_by(scm.resolve_rev, revs).items():
-        self.tree = CleanTree(scm.get_tree(sha))
-        yield ", ".join(names)
-
-    self.tree = saved_tree
+    try:
+        for sha, names in group_by(scm.resolve_rev, revs).items():
+            self.tree = CleanTree(scm.get_tree(sha))
+            yield ", ".join(names)
+    finally:
+        self.tree = saved_tree