dulwich/tests/test_rebase.py

# test_rebase.py -- rebase tests
# Copyright (C) 2025 Dulwich contributors
#
# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
# General Public License as published by the Free Software Foundation; version 2.0
# or (at your option) any later version. You can redistribute it and/or
# modify it under the terms of either of these two licenses.
#
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
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# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
# License, Version 2.0.
#

"""Tests for dulwich.rebase."""

import importlib.util
import os
import tempfile

from dulwich.objects import Blob, Commit, Tree
from dulwich.rebase import (
    RebaseConflict,
    Rebaser,
    RebaseTodo,
    RebaseTodoCommand,
    RebaseTodoEntry,
    process_interactive_rebase,
    rebase,
    start_interactive,
)
from dulwich.repo import MemoryRepo, Repo
from dulwich.tests.utils import make_commit

from . import DependencyMissing, TestCase


class RebaserTestCase(TestCase):
    """Tests for the Rebaser class."""

    def setUp(self):
        """Set up test repository."""
        super().setUp()
        self.repo = MemoryRepo()
        self.addCleanup(self.repo.close)

    def _setup_initial_commit(self):
        """Set up initial commit for tests."""
        # Create initial commit
        blob = Blob.from_string(b"Initial content\n")
        self.repo.object_store.add_object(blob)

        tree = Tree()
        tree.add(b"file.txt", 0o100644, blob.id)
        self.repo.object_store.add_object(tree)

        self.initial_commit = make_commit(
            tree=tree.id,
            parents=[],
            message=b"Initial commit",
            committer=b"Test User <test@example.com>",
            author=b"Test User <test@example.com>",
            commit_time=1000000,
            author_time=1000000,
            commit_timezone=0,
            author_timezone=0,
        )
        self.repo.object_store.add_object(self.initial_commit)

        # Set up branches
        self.repo.refs[b"refs/heads/master"] = self.initial_commit.id
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/master")

    def test_simple_rebase(self):
        """Test simple rebase with no conflicts."""
        self._setup_initial_commit()
        # Create feature branch with one commit
        feature_blob = Blob.from_string(b"Feature content\n")
        self.repo.object_store.add_object(feature_blob)

        feature_tree = Tree()
        feature_tree.add(b"feature.txt", 0o100644, feature_blob.id)
        feature_tree.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(feature_tree)

        feature_commit = Commit()
        feature_commit.tree = feature_tree.id
        feature_commit.parents = [self.initial_commit.id]
        feature_commit.message = b"Add feature"
        feature_commit.committer = b"Test User <test@example.com>"
        feature_commit.author = b"Test User <test@example.com>"
        feature_commit.commit_time = 1000100
        feature_commit.author_time = 1000100
        feature_commit.commit_timezone = 0
        feature_commit.author_timezone = 0
        self.repo.object_store.add_object(feature_commit)
        self.repo.refs[b"refs/heads/feature"] = feature_commit.id

        # Create main branch advancement
        main_blob = Blob.from_string(b"Main advancement\n")
        self.repo.object_store.add_object(main_blob)

        main_tree = Tree()
        main_tree.add(b"main.txt", 0o100644, main_blob.id)
        main_tree.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(main_tree)

        main_commit = Commit()
        main_commit.tree = main_tree.id
        main_commit.parents = [self.initial_commit.id]
        main_commit.message = b"Main advancement"
        main_commit.committer = b"Test User <test@example.com>"
        main_commit.author = b"Test User <test@example.com>"
        main_commit.commit_time = 1000200
        main_commit.author_time = 1000200
        main_commit.commit_timezone = 0
        main_commit.author_timezone = 0
        self.repo.object_store.add_object(main_commit)
        self.repo.refs[b"refs/heads/master"] = main_commit.id

        # Switch to feature branch
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/feature")

        # Check refs before rebase
        main_ref_before = self.repo.refs[b"refs/heads/master"]
        feature_ref_before = self.repo.refs[b"refs/heads/feature"]

        # Double check that refs are correctly set up
        self.assertEqual(main_ref_before, main_commit.id)
        self.assertEqual(feature_ref_before, feature_commit.id)

        # Perform rebase
        rebaser = Rebaser(self.repo)
        commits = rebaser.start(b"refs/heads/master", branch=b"refs/heads/feature")

        self.assertEqual(len(commits), 1)
        self.assertEqual(commits[0].id, feature_commit.id)

        # Continue rebase
        result = rebaser.continue_()
        self.assertIsNone(result)  # Rebase complete

        # Check that feature branch was updated
        new_feature_head = self.repo.refs[b"refs/heads/feature"]
        new_commit = self.repo[new_feature_head]

        # Should have main commit as parent
        self.assertEqual(new_commit.parents, [main_commit.id])

        # Should have same tree as original (both files present)
        new_tree = self.repo[new_commit.tree]
        self.assertIn(b"feature.txt", new_tree)
        self.assertIn(b"main.txt", new_tree)
        self.assertIn(b"file.txt", new_tree)

    def test_rebase_with_conflicts(self):
        # Check if merge3 module is available
        if importlib.util.find_spec("merge3") is None:
            raise DependencyMissing("merge3")

        """Test rebase with merge conflicts."""
        self._setup_initial_commit()
        # Create feature branch with conflicting change
        feature_blob = Blob.from_string(b"Feature change to file\n")
        self.repo.object_store.add_object(feature_blob)

        feature_tree = Tree()
        feature_tree.add(b"file.txt", 0o100644, feature_blob.id)
        self.repo.object_store.add_object(feature_tree)

        feature_commit = Commit()
        feature_commit.tree = feature_tree.id
        feature_commit.parents = [self.initial_commit.id]
        feature_commit.message = b"Feature change"
        feature_commit.committer = b"Test User <test@example.com>"
        feature_commit.author = b"Test User <test@example.com>"
        feature_commit.commit_time = 1000100
        feature_commit.author_time = 1000100
        feature_commit.commit_timezone = 0
        feature_commit.author_timezone = 0
        self.repo.object_store.add_object(feature_commit)
        self.repo.refs[b"refs/heads/feature"] = feature_commit.id

        # Create main branch with conflicting change
        main_blob = Blob.from_string(b"Main change to file\n")
        self.repo.object_store.add_object(main_blob)

        main_tree = Tree()
        main_tree.add(b"file.txt", 0o100644, main_blob.id)
        self.repo.object_store.add_object(main_tree)

        main_commit = Commit()
        main_commit.tree = main_tree.id
        main_commit.parents = [self.initial_commit.id]
        main_commit.message = b"Main change"
        main_commit.committer = b"Test User <test@example.com>"
        main_commit.author = b"Test User <test@example.com>"
        main_commit.commit_time = 1000200
        main_commit.author_time = 1000200
        main_commit.commit_timezone = 0
        main_commit.author_timezone = 0
        self.repo.object_store.add_object(main_commit)
        self.repo.refs[b"refs/heads/master"] = main_commit.id

        # Attempt rebase - should fail with conflicts
        with self.assertRaises(RebaseConflict) as cm:
            rebase(self.repo, b"refs/heads/master", branch=b"refs/heads/feature")

        self.assertIn(b"file.txt", cm.exception.conflicted_files)

    def test_abort_rebase(self):
        """Test aborting a rebase."""
        self._setup_initial_commit()
        # Set up branches similar to simple rebase test
        feature_blob = Blob.from_string(b"Feature content\n")
        self.repo.object_store.add_object(feature_blob)

        feature_tree = Tree()
        feature_tree.add(b"feature.txt", 0o100644, feature_blob.id)
        feature_tree.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(feature_tree)

        feature_commit = Commit()
        feature_commit.tree = feature_tree.id
        feature_commit.parents = [self.initial_commit.id]
        feature_commit.message = b"Add feature"
        feature_commit.committer = b"Test User <test@example.com>"
        feature_commit.author = b"Test User <test@example.com>"
        feature_commit.commit_time = 1000100
        feature_commit.author_time = 1000100
        feature_commit.commit_timezone = 0
        feature_commit.author_timezone = 0
        self.repo.object_store.add_object(feature_commit)
        self.repo.refs[b"refs/heads/feature"] = feature_commit.id
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/feature")

        # Start rebase
        rebaser = Rebaser(self.repo)
        rebaser.start(b"refs/heads/master")

        # Abort rebase
        rebaser.abort()

        # Check that HEAD is restored
        self.assertEqual(self.repo.refs.read_ref(b"HEAD"), b"ref: refs/heads/feature")
        self.assertEqual(self.repo.refs[b"refs/heads/feature"], feature_commit.id)

        # Check that REBASE_HEAD is cleaned up
        self.assertNotIn(b"REBASE_HEAD", self.repo.refs)

    def test_rebase_no_commits(self):
        """Test rebase when already up to date."""
        self._setup_initial_commit()
        # Both branches point to same commit
        self.repo.refs[b"refs/heads/feature"] = self.initial_commit.id
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/feature")

        # Perform rebase
        result = rebase(self.repo, b"refs/heads/master")

        # Should return empty list (no new commits)
        self.assertEqual(result, [])

    def test_rebase_onto(self):
        """Test rebase with --onto option."""
        self._setup_initial_commit()
        # Create a chain of commits: initial -> A -> B -> C
        blob_a = Blob.from_string(b"Commit A\n")
        self.repo.object_store.add_object(blob_a)

        tree_a = Tree()
        tree_a.add(b"a.txt", 0o100644, blob_a.id)
        tree_a.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(tree_a)

        commit_a = make_commit(
            id=b"a" * 40,
            tree=tree_a.id,
            parents=[self.initial_commit.id],
            message=b"Commit A",
            committer=b"Test User <test@example.com>",
            author=b"Test User <test@example.com>",
            commit_time=1000100,
            author_time=1000100,
        )
        self.repo.object_store.add_object(commit_a)

        blob_b = Blob.from_string(b"Commit B\n")
        self.repo.object_store.add_object(blob_b)

        tree_b = Tree()
        tree_b.add(b"b.txt", 0o100644, blob_b.id)
        tree_b.add(b"a.txt", 0o100644, blob_a.id)
        tree_b.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(tree_b)

        commit_b = make_commit(
            id=b"b" * 40,
            tree=tree_b.id,
            parents=[commit_a.id],
            message=b"Commit B",
            committer=b"Test User <test@example.com>",
            author=b"Test User <test@example.com>",
            commit_time=1000200,
            author_time=1000200,
        )
        self.repo.object_store.add_object(commit_b)

        blob_c = Blob.from_string(b"Commit C\n")
        self.repo.object_store.add_object(blob_c)

        tree_c = Tree()
        tree_c.add(b"c.txt", 0o100644, blob_c.id)
        tree_c.add(b"b.txt", 0o100644, blob_b.id)
        tree_c.add(b"a.txt", 0o100644, blob_a.id)
        tree_c.add(
            b"file.txt", 0o100644, self.repo[self.initial_commit.tree][b"file.txt"][1]
        )
        self.repo.object_store.add_object(tree_c)

        commit_c = make_commit(
            id=b"c" * 40,
            tree=tree_c.id,
            parents=[commit_b.id],
            message=b"Commit C",
            committer=b"Test User <test@example.com>",
            author=b"Test User <test@example.com>",
            commit_time=1000300,
            author_time=1000300,
        )
        self.repo.object_store.add_object(commit_c)

        # Create separate branch at commit A
        self.repo.refs[b"refs/heads/topic"] = commit_c.id
        self.repo.refs[b"refs/heads/newbase"] = commit_a.id
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/topic")

        # Rebase B and C onto initial commit (skipping A)
        rebaser = Rebaser(self.repo)
        commits = rebaser.start(
            upstream=commit_a.id,
            onto=self.initial_commit.id,
            branch=b"refs/heads/topic",
        )

        # Should rebase commits B and C
        self.assertEqual(len(commits), 2)
        self.assertEqual(commits[0].id, commit_b.id)
        self.assertEqual(commits[1].id, commit_c.id)

        # Continue rebase
        result = rebaser.continue_()
        self.assertIsNone(result)

        # Check result
        new_head = self.repo.refs[b"refs/heads/topic"]
        new_c = self.repo[new_head]
        new_b = self.repo[new_c.parents[0]]

        # B should now have initial commit as parent (not A)
        self.assertEqual(new_b.parents, [self.initial_commit.id])

        # Trees should still have b.txt and c.txt but not a.txt
        new_b_tree = self.repo[new_b.tree]
        self.assertIn(b"b.txt", new_b_tree)
        self.assertNotIn(b"a.txt", new_b_tree)

        new_c_tree = self.repo[new_c.tree]
        self.assertIn(b"c.txt", new_c_tree)
        self.assertIn(b"b.txt", new_c_tree)
        self.assertNotIn(b"a.txt", new_c_tree)


class InteractiveRebaseTestCase(TestCase):
    """Tests for interactive rebase functionality."""

    def setUp(self):
        """Set up test repository."""
        super().setUp()
        self.repo = MemoryRepo()
        self.addCleanup(self.repo.close)
        self._setup_initial_commit()

    def _setup_initial_commit(self):
        """Set up initial commit for tests."""
        # Create initial commit
        blob = Blob.from_string(b"Initial content\n")
        self.repo.object_store.add_object(blob)

        tree = Tree()
        tree.add(b"file.txt", 0o100644, blob.id)
        self.repo.object_store.add_object(tree)

        self.initial_commit = make_commit(
            tree=tree.id,
            parents=[],
            message=b"Initial commit",
            committer=b"Test User <test@example.com>",
            author=b"Test User <test@example.com>",
            commit_time=1000000,
            author_time=1000000,
            commit_timezone=0,
            author_timezone=0,
        )
        self.repo.object_store.add_object(self.initial_commit)

        # Set up branches
        self.repo.refs[b"refs/heads/master"] = self.initial_commit.id
        self.repo.refs.set_symbolic_ref(b"HEAD", b"refs/heads/master")

    def _create_test_commits(self):
        """Create a series of test commits for interactive rebase."""
        commits = []
        parent = self.initial_commit.id

        for i in range(3):
            blob = Blob.from_string(f"Content {i}\n".encode())
            self.repo.object_store.add_object(blob)

            tree = Tree()
            tree.add(f"file{i}.txt".encode(), 0o100644, blob.id)
            self.repo.object_store.add_object(tree)

            commit = Commit()
            commit.tree = tree.id
            commit.parents = [parent]
            commit.message = f"Commit {i}".encode()
            commit.committer = b"Test User <test@example.com>"
            commit.author = b"Test User <test@example.com>"
            commit.commit_time = 1000000 + i * 100
            commit.author_time = 1000000 + i * 100
            commit.commit_timezone = 0
            commit.author_timezone = 0
            self.repo.object_store.add_object(commit)

            commits.append(commit)
            parent = commit.id

        self.repo.refs[b"refs/heads/feature"] = commits[-1].id
        return commits

    def test_todo_parsing(self):
        """Test parsing of todo file format."""
        todo_content = """pick 1234567 First commit
reword 2345678 Second commit
edit 3456789 Third commit
squash 4567890 Fourth commit
fixup 5678901 Fifth commit
drop 6789012 Sixth commit
exec echo "Running test"
break
# This is a comment
"""
        todo = RebaseTodo.from_string(todo_content)

        self.assertEqual(len(todo.entries), 8)

        # Check first entry
        self.assertEqual(todo.entries[0].command, RebaseTodoCommand.PICK)
        self.assertEqual(todo.entries[0].commit_sha, b"1234567")
        self.assertEqual(todo.entries[0].short_message, "First commit")

        # Check reword
        self.assertEqual(todo.entries[1].command, RebaseTodoCommand.REWORD)

        # Check exec
        self.assertEqual(todo.entries[6].command, RebaseTodoCommand.EXEC)
        self.assertEqual(todo.entries[6].arguments, 'echo "Running test"')

        # Check break
        self.assertEqual(todo.entries[7].command, RebaseTodoCommand.BREAK)

    def test_todo_generation(self):
        """Test generation of todo list from commits."""
        commits = self._create_test_commits()
        todo = RebaseTodo.from_commits(commits)

        # Should have one pick entry per commit
        self.assertEqual(len(todo.entries), 3)

        for i, entry in enumerate(todo.entries):
            self.assertEqual(entry.command, RebaseTodoCommand.PICK)
            # commit_sha stores the full hex SHA as bytes
            self.assertEqual(entry.commit_sha, commits[i].id)
            self.assertIn(f"Commit {i}", entry.short_message)

    def test_todo_serialization(self):
        """Test serialization of todo list."""
        entries = [
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=b"1234567890abcdef",
                short_message="First commit",
            ),
            RebaseTodoEntry(
                command=RebaseTodoCommand.SQUASH,
                commit_sha=b"fedcba0987654321",
                short_message="Second commit",
            ),
            RebaseTodoEntry(command=RebaseTodoCommand.EXEC, arguments="make test"),
        ]

        todo = RebaseTodo(entries)
        content = todo.to_string(include_comments=False)

        lines = content.strip().split("\n")
        self.assertEqual(len(lines), 3)
        self.assertIn("pick 1234567", lines[0])
        self.assertIn("squash fedcba0", lines[1])
        self.assertIn("exec make test", lines[2])

    def test_start_interactive_no_editor(self):
        """Test starting interactive rebase without editor."""
        self._create_test_commits()

        # Start interactive rebase
        todo = start_interactive(
            self.repo,
            b"refs/heads/master",
            branch=b"refs/heads/feature",
            editor_callback=None,
        )

        # Should have generated todo list
        self.assertEqual(len(todo.entries), 3)
        for entry in todo.entries:
            self.assertEqual(entry.command, RebaseTodoCommand.PICK)

    def test_start_interactive_with_editor(self):
        """Test starting interactive rebase with editor callback."""
        self._create_test_commits()

        def mock_editor(content):
            # Simulate user changing pick to squash for second commit
            lines = content.decode().splitlines()
            new_lines = []
            for i, line in enumerate(lines):
                if i == 1 and line.startswith("pick"):
                    new_lines.append(line.replace("pick", "squash"))
                else:
                    new_lines.append(line)
            return "\n".join(new_lines).encode()

        todo = start_interactive(
            self.repo,
            b"refs/heads/master",
            branch=b"refs/heads/feature",
            editor_callback=mock_editor,
        )

        # Second entry should be squash
        self.assertEqual(todo.entries[0].command, RebaseTodoCommand.PICK)
        self.assertEqual(todo.entries[1].command, RebaseTodoCommand.SQUASH)
        self.assertEqual(todo.entries[2].command, RebaseTodoCommand.PICK)

    def test_process_drop_command(self):
        """Test processing DROP command in interactive rebase."""
        commits = self._create_test_commits()

        # Create todo with drop command
        entries = [
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=commits[0].id,
                short_message="Commit 0",
            ),
            RebaseTodoEntry(
                command=RebaseTodoCommand.DROP,
                commit_sha=commits[1].id,
                short_message="Commit 1",
            ),
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=commits[2].id,
                short_message="Commit 2",
            ),
        ]

        todo = RebaseTodo(entries)
        is_complete, pause_reason = process_interactive_rebase(self.repo, todo)

        # Should complete successfully
        self.assertTrue(is_complete)
        self.assertIsNone(pause_reason)

        # Should have only picked 2 commits (dropped one)
        # Note: _done list would contain the rebased commits

    def test_process_break_command(self):
        """Test processing BREAK command in interactive rebase."""
        commits = self._create_test_commits()

        entries = [
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=commits[0].id,
                short_message="Commit 0",
            ),
            RebaseTodoEntry(command=RebaseTodoCommand.BREAK),
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=commits[1].id,
                short_message="Commit 1",
            ),
        ]

        todo = RebaseTodo(entries)
        is_complete, pause_reason = process_interactive_rebase(self.repo, todo)

        # Should pause at break
        self.assertFalse(is_complete)
        self.assertEqual(pause_reason, "break")

        # Todo should be at position after break
        self.assertEqual(todo.current_index, 2)

    def test_process_edit_command(self):
        """Test processing EDIT command in interactive rebase."""
        commits = self._create_test_commits()

        entries = [
            RebaseTodoEntry(
                command=RebaseTodoCommand.PICK,
                commit_sha=commits[0].id,
                short_message="Commit 0",
            ),
            RebaseTodoEntry(
                command=RebaseTodoCommand.EDIT,
                commit_sha=commits[1].id,
                short_message="Commit 1",
            ),
        ]

        todo = RebaseTodo(entries)
        is_complete, pause_reason = process_interactive_rebase(self.repo, todo)

        # Should pause for editing
        self.assertFalse(is_complete)
        self.assertEqual(pause_reason, "edit")

    def test_abbreviations(self):
        """Test parsing abbreviated commands."""
        todo_content = """p 1234567 Pick
r 2345678 Reword
e 3456789 Edit
s 4567890 Squash
f 5678901 Fixup
d 6789012 Drop
x echo test
b
"""
        todo = RebaseTodo.from_string(todo_content)

        self.assertEqual(todo.entries[0].command, RebaseTodoCommand.PICK)
        self.assertEqual(todo.entries[1].command, RebaseTodoCommand.REWORD)
        self.assertEqual(todo.entries[2].command, RebaseTodoCommand.EDIT)
        self.assertEqual(todo.entries[3].command, RebaseTodoCommand.SQUASH)
        self.assertEqual(todo.entries[4].command, RebaseTodoCommand.FIXUP)
        self.assertEqual(todo.entries[5].command, RebaseTodoCommand.DROP)
        self.assertEqual(todo.entries[6].command, RebaseTodoCommand.EXEC)
        self.assertEqual(todo.entries[7].command, RebaseTodoCommand.BREAK)