Stage: create: reset repo when removing existing stage

dvc/repo/__init__.py

@@ -24,6 +24,7 @@ def locked(f):
     @wraps(f)
     def wrapper(repo, *args, **kwargs):
         with repo.lock, repo.state:
+            repo._reset()
             ret = f(repo, *args, **kwargs)
             # Our graph cache is no longer valid after we release the repo.lock
             repo._reset()

dvc/repo/add.py

@@ -126,6 +126,7 @@ def _create_stages(repo, targets, fname, pbar=None):
         stage = Stage.create(
             repo, outs=[out], accompany_outs=True, fname=fname
         )
+        repo._reset()
 
         if not stage:
             if pbar is not None:

tests/func/test_add.py

@@ -655,3 +655,10 @@ def test_add_from_data_dir(tmp_dir, scm, dvc):
         "tracked output: 'dir'.\n"
         "To include '{out}' in 'dir', run 'dvc commit dir.dvc'"
     ).format(out=os.path.join("dir", "file2"))
+
+
+def test_not_raises_on_re_add(tmp_dir, dvc):
+    tmp_dir.dvc_gen("file", "file content")
+
+    tmp_dir.gen({"file2": "file2 content", "file": "modified file"})
+    dvc.add(["file2", "file"])

tests/unit/repo/test_repo.py

@@ -2,6 +2,8 @@
 
 import pytest
 
+from dvc.repo import locked
+
 
 def test_is_dvc_internal(dvc):
     assert dvc.is_dvc_internal(os.path.join("path", "to", ".dvc", "file"))
@@ -49,3 +51,18 @@ def test_used_cache(tmp_dir, dvc, path):
             used_cache._items == expected._items
             and used_cache.external == expected.external
         )
+
+
+def test_locked(mocker):
+    repo = mocker.MagicMock()
+    repo.method = locked(repo.method)
+
+    args = {}
+    kwargs = {}
+    repo.method(repo, args, kwargs)
+
+    assert repo.method_calls == [
+        mocker.call._reset(),
+        mocker.call.method(repo, args, kwargs),
+        mocker.call._reset(),
+    ]