Implement Branch.cherry_pick() (#7348)

* Implement `Branch.cherry_pick()`

As a minimal wrapper around `BranchesApi.cherry_pick()`. Since the API
returns the created commit , we return the corresponding SDK wrapper
model constructed directly from the API response.

Adds an integration test cherry-picking a commit onto main, checking
metadata and message equality.

* Tweak parent_number description in cherry-pick API and Python docstring

* Add `force` option to `Branch.cherry_pick()`

In line with the cherry pick API, currently a no-op.

* Revert "Add `force` option to `Branch.cherry_pick()`"

This reverts commit fbe4027.

* Add line break to parent_number docstring to satisfy pylint

* fix generated docs

* fix generated docs 2

* fix generated docs 3

---------

Co-authored-by: Nir Ozery <[email protected]>

api/swagger.yml

@@ -537,8 +537,8 @@ components:
         parent_number:
           type: integer
           description: |
-            when cherry-picking a merge commit, the parent number (starting from 1) relative to which to perform the diff.
-            The destination branch is parent 1, which is the default behaviour.
+            When cherry-picking a merge commit, the parent number (starting from 1) with which to perform the diff.
+            The default branch is parent 1.
         force:
           type: boolean
           default: false

clients/python-wrapper/lakefs/branch.py

@@ -14,7 +14,7 @@
 from lakefs.object import StoredObject
 from lakefs.import_manager import ImportManager
 from lakefs.reference import Reference, ReferenceType, generate_listing
-from lakefs.models import Change
+from lakefs.models import Change, Commit
 from lakefs.exceptions import (
     api_exception_handler,
     ConflictException,
@@ -124,6 +124,24 @@ def get_commit(self):
         self._commit = None
         return super().get_commit()
 
+    def cherry_pick(self, reference: ReferenceType, parent_number: Optional[int] = None) -> Commit:
+        """
+        Cherry-pick a given reference onto the branch.
+
+        :param reference: ID of the reference to cherry-pick.
+        :param parent_number: When cherry-picking a merge commit, the parent number (starting from 1)
+            with which to perform the diff. The default branch is parent 1.
+        :return: The cherry-picked commit at the head of the branch.
+        :raise NotFoundException: If either the repository or target reference do not exist.
+        :raise NotAuthorizedException: If the user is not authorized to perform this operation.
+        :raise ServerException: For any other errors.
+        """
+        ref = reference if isinstance(reference, str) else reference.id
+        cherry_pick_creation = lakefs_sdk.CherryPickCreation(ref=ref, parent_number=parent_number)
+        with api_exception_handler():
+            res = self._client.sdk_client.branches_api.cherry_pick(self._repo_id, self._id, cherry_pick_creation)
+            return Commit(**res.dict())
+
     def create(self, source_reference: ReferenceType, exist_ok: bool = False) -> Branch:
         """
         Create a new branch in lakeFS from this object

clients/python-wrapper/tests/integration/test_branch.py

@@ -26,6 +26,26 @@ def test_revert(setup_repo):
         assert fd.read() == initial_content
 
 
+def test_cherry_pick(setup_repo):
+    _, repo = setup_repo
+    main_branch = repo.branch("main")
+    test_branch = repo.branch("testest").create("main")
+
+    initial_content = "test_content"
+    test_branch.object("test_object").upload(initial_content)
+    testcommit = test_branch.commit("test_commit", {"test_key": "test_value"}).get_commit()
+
+    cherry_picked = main_branch.cherry_pick(test_branch.head)
+    assert test_branch.object("test_object").exists()
+    # SHAs are not equal, so we exclude them from eq checks.
+    assert cherry_picked.message == testcommit.message
+    # cherry-picks have origin and source ref name attached as metadata (at minimum),
+    # so we only check that the additional user-supplied metadata is present.
+    assert set(testcommit.metadata.items()) <= set(cherry_picked.metadata.items())
+    # check that the cherry-pick origin is exactly testest@HEAD.
+    assert cherry_picked.metadata["cherry-pick-origin"] == testcommit.id
+
+
 def test_reset_changes(setup_repo):
     _, repo = setup_repo
     test_branch = repo.branch("main")

docs/assets/js/swagger.yml

@@ -537,8 +537,8 @@ components:
         parent_number:
           type: integer
           description: |
-            when cherry-picking a merge commit, the parent number (starting from 1) relative to which to perform the diff.
-            The destination branch is parent 1, which is the default behaviour.
+            When cherry-picking a merge commit, the parent number (starting from 1) with which to perform the diff.
+            The default branch is parent 1.
         force:
           type: boolean
           default: false