Add Repository.amend_commit

pygit2/_run.py

@@ -77,6 +77,7 @@
     'net.h',
     'refspec.h',
     'repository.h',
+    'commit.h',
     'revert.h',
     'stash.h',
     'submodule.h',

pygit2/decl/commit.h

@@ -0,0 +1,9 @@
+int git_commit_amend(
+    git_oid *id,
+    const git_commit *commit_to_amend,
+    const char *update_ref,
+    const git_signature *author,
+    const git_signature *committer,
+    const char *message_encoding,
+    const char *message,
+    const git_tree *tree);

pygit2/repository.py

@@ -37,7 +37,7 @@
 from ._pygit2 import GIT_FILEMODE_LINK
 from ._pygit2 import GIT_BRANCH_LOCAL, GIT_BRANCH_REMOTE, GIT_BRANCH_ALL
 from ._pygit2 import GIT_REF_SYMBOLIC
-from ._pygit2 import Reference, Tree, Commit, Blob
+from ._pygit2 import Reference, Tree, Commit, Blob, Signature
 from ._pygit2 import InvalidSpecError
 
 from .callbacks import git_fetch_options
@@ -1364,6 +1364,119 @@ def revert_commit(self, revert_commit, our_commit, mainline=0):
 
         return Index.from_c(self, cindex)
 
+    #
+    # Amend commit
+    #
+    def amend_commit(self, commit, refname, author=None,
+                     committer=None, message=None, tree=None,
+                     encoding='UTF-8'):
+        """
+        Amend an existing commit by replacing only explicitly passed values,
+        return the rewritten commit's oid.
+
+        This creates a new commit that is exactly the same as the old commit,
+        except that any explicitly passed values will be updated. The new
+        commit has the same parents as the old commit.
+
+        You may omit the `author`, `committer`, `message`, `tree`, and
+        `encoding` parameters, in which case this will use the values
+        from the original `commit`.
+
+        Parameters:
+
+        commit : Commit, Oid, or str
+            The commit to amend.
+
+        refname : Reference or str
+            If not `None`, name of the reference that will be updated to point
+            to the newly rewritten commit. Use "HEAD" to update the HEAD of the
+            current branch and make it point to the rewritten commit.
+            If you want to amend a commit that is not currently the tip of the
+            branch and then rewrite the following commits to reach a ref, pass
+            this as `None` and update the rest of the commit chain and ref
+            separately.
+
+        author : Signature
+            If not None, replace the old commit's author signature with this
+            one.
+
+        committer : Signature
+            If not None, replace the old commit's committer signature with this
+            one.
+
+        message : str
+            If not None, replace the old commit's message with this one.
+
+        tree : Tree, Oid, or str
+            If not None, replace the old commit's tree with this one.
+
+        encoding : str
+            Optional encoding for `message`.
+        """
+
+        # Initialize parameters to pass on to C function git_commit_amend.
+        # Note: the pointers are all initialized to NULL by default.
+        coid = ffi.new('git_oid *')
+        commit_cptr = ffi.new('git_commit **')
+        refname_cstr = ffi.NULL
+        author_cptr = ffi.new('git_signature **')
+        committer_cptr = ffi.new('git_signature **')
+        message_cstr = ffi.NULL
+        encoding_cstr = ffi.NULL
+        tree_cptr = ffi.new('git_tree **')
+
+        # Get commit as pointer to git_commit.
+        if isinstance(commit, (str, Oid)):
+            commit = self[commit]
+        elif isinstance(commit, Commit):
+            pass
+        elif commit is None:
+            raise ValueError("the commit to amend cannot be None")
+        else:
+            raise TypeError("the commit to amend must be a Commit, str, or Oid")
+        commit = commit.peel(Commit)
+        ffi.buffer(commit_cptr)[:] = commit._pointer[:]
+
+        # Get refname as C string.
+        if isinstance(refname, Reference):
+            refname_cstr = ffi.new('char[]', to_bytes(refname.name))
+        elif type(refname) is str:
+            refname_cstr = ffi.new('char[]', to_bytes(refname))
+        elif refname is not None:
+            raise TypeError("refname must be a str or Reference")
+
+        # Get author as pointer to git_signature.
+        if isinstance(author, Signature):
+            ffi.buffer(author_cptr)[:] = author._pointer[:]
+        elif author is not None:
+            raise TypeError("author must be a Signature")
+
+        # Get committer as pointer to git_signature.
+        if isinstance(committer, Signature):
+            ffi.buffer(committer_cptr)[:] = committer._pointer[:]
+        elif committer is not None:
+            raise TypeError("committer must be a Signature")
+
+        # Get message and encoding as C strings.
+        if message is not None:
+            message_cstr = ffi.new('char[]', to_bytes(message, encoding))
+            encoding_cstr = ffi.new('char[]', to_bytes(encoding))
+
+        # Get tree as pointer to git_tree.
+        if tree is not None:
+            if isinstance(tree, (str, Oid)):
+                tree = self[tree]
+            tree = tree.peel(Tree)
+            ffi.buffer(tree_cptr)[:] = tree._pointer[:]
+
+        # Amend the commit.
+        err = C.git_commit_amend(coid, commit_cptr[0], refname_cstr,
+                                 author_cptr[0], committer_cptr[0],
+                                 encoding_cstr, message_cstr, tree_cptr[0])
+        check_error(err)
+
+        return Oid(raw=bytes(ffi.buffer(coid)[:]))
+
 
 class Branches:
 

test/test_commit.py

@@ -29,11 +29,12 @@
 
 import pytest
 
-from pygit2 import GIT_OBJ_COMMIT, Signature, Oid
+from pygit2 import GIT_OBJ_COMMIT, Signature, Oid, GitError
 from . import utils
 
 
 COMMIT_SHA = '5fe808e8953c12735680c257f56600cb0de44b10'
+COMMIT_SHA_TO_AMEND = '784855caf26449a1914d2cf62d12b9374d76ae78'  # tip of the master branch
 
 
 @utils.refcount
@@ -133,3 +134,116 @@ def test_modify_commit(barerepo):
     with pytest.raises(AttributeError): setattr(commit, 'author', author)
     with pytest.raises(AttributeError): setattr(commit, 'tree', None)
     with pytest.raises(AttributeError): setattr(commit, 'parents', None)
+
+def test_amend_commit_metadata(barerepo):
+    repo = barerepo
+    commit = repo[COMMIT_SHA_TO_AMEND]
+    assert commit.oid == repo.head.target
+
+    encoding = 'iso-8859-1'
+    amended_message = "Amended commit message.\n\nMessage with non-ascii chars: ééé.\n"
+    amended_author = Signature('Jane Author', '[email protected]', 12345, 0)
+    amended_committer = Signature('John Committer', '[email protected]', 12346, 0)
+
+    amended_oid = repo.amend_commit(
+        commit, 'HEAD', message=amended_message, author=amended_author,
+        committer=amended_committer, encoding=encoding)
+    amended_commit = repo[amended_oid]
+
+    assert repo.head.target == amended_oid
+    assert GIT_OBJ_COMMIT == amended_commit.type
+    assert amended_committer == amended_commit.committer
+    assert amended_author == amended_commit.author
+    assert amended_message.encode(encoding) == amended_commit.raw_message
+    assert commit.author != amended_commit.author
+    assert commit.committer != amended_commit.committer
+    assert commit.tree == amended_commit.tree  # we didn't touch the tree
+
+def test_amend_commit_tree(barerepo):
+    repo = barerepo
+    commit = repo[COMMIT_SHA_TO_AMEND]
+    assert commit.oid == repo.head.target
+
+    tree = '967fce8df97cc71722d3c2a5930ef3e6f1d27b12'
+    tree_prefix = tree[:5]
+
+    amended_oid = repo.amend_commit(commit, 'HEAD', tree=tree_prefix)
+    amended_commit = repo[amended_oid]
+
+    assert repo.head.target == amended_oid
+    assert GIT_OBJ_COMMIT == amended_commit.type
+    assert commit.message == amended_commit.message
+    assert commit.author == amended_commit.author
+    assert commit.committer == amended_commit.committer
+    assert commit.tree_id != amended_commit.tree_id
+    assert Oid(hex=tree) == amended_commit.tree_id
+
+def test_amend_commit_not_tip_of_branch(barerepo):
+    repo = barerepo
+
+    # This commit isn't at the tip of the branch.
+    commit = repo['5fe808e8953c12735680c257f56600cb0de44b10']
+    assert commit.oid != repo.head.target
+
+    # Can't update HEAD to the rewritten commit because it's not the tip of the branch.
+    with pytest.raises(GitError):
+        repo.amend_commit(commit, 'HEAD', message="this won't work!")
+
+    # We can still amend the commit if we don't try to update a ref.
+    repo.amend_commit(commit, None, message="this will work")
+
+def test_amend_commit_no_op(barerepo):
+    repo = barerepo
+    commit = repo[COMMIT_SHA_TO_AMEND]
+    assert commit.oid == repo.head.target
+
+    amended_oid = repo.amend_commit(commit, None)
+    assert amended_oid == commit.oid
+
+def test_amend_commit_argument_types(barerepo):
+    repo = barerepo
+
+    some_tree = repo['967fce8df97cc71722d3c2a5930ef3e6f1d27b12']
+    commit = repo[COMMIT_SHA_TO_AMEND]
+    alt_commit1 = Oid(hex=COMMIT_SHA_TO_AMEND)
+    alt_commit2 = COMMIT_SHA_TO_AMEND
+    alt_tree = some_tree
+    alt_refname = repo.head  # try this one last, because it'll change the commit at the tip
+
+    # Pass bad values/types for the commit
+    with pytest.raises(ValueError): repo.amend_commit(None, None)
+    with pytest.raises(TypeError): repo.amend_commit(some_tree, None)
+
+    # Pass bad types for signatures
+    with pytest.raises(TypeError): repo.amend_commit(commit, None, author="Toto")
+    with pytest.raises(TypeError): repo.amend_commit(commit, None, committer="Toto")
+
+    # Pass bad refnames
+    with pytest.raises(ValueError): repo.amend_commit(commit, "this-ref-doesnt-exist")
+    with pytest.raises(TypeError): repo.amend_commit(commit, repo)
+
+    # Pass bad trees
+    with pytest.raises(ValueError): repo.amend_commit(commit, None, tree="can't parse this")
+    with pytest.raises(KeyError): repo.amend_commit(commit, None, tree="baaaaad")
+
+    # Pass an Oid for the commit
+    amended_oid = repo.amend_commit(alt_commit1, None, message="Hello")
+    amended_commit = repo[amended_oid]
+    assert GIT_OBJ_COMMIT == amended_commit.type
+    assert str(amended_oid) != COMMIT_SHA_TO_AMEND
+
+    # Pass a str for the commit
+    amended_oid = repo.amend_commit(alt_commit2, None, message="Hello", tree=alt_tree)
+    amended_commit = repo[amended_oid]
+    assert GIT_OBJ_COMMIT == amended_commit.type
+    assert str(amended_oid) != COMMIT_SHA_TO_AMEND
+    assert repo[COMMIT_SHA_TO_AMEND].tree != amended_commit.tree
+    assert alt_tree.oid == amended_commit.tree_id
+
+    # Pass an actual reference object for refname
+    # (Warning: the tip of the branch will be altered after this test!)
+    amended_oid = repo.amend_commit(alt_commit2, alt_refname, message="Hello")
+    amended_commit = repo[amended_oid]
+    assert GIT_OBJ_COMMIT == amended_commit.type
+    assert str(amended_oid) != COMMIT_SHA_TO_AMEND
+    assert repo.head.target == amended_oid