mechanical-refactor-verify

1import subprocess2import sys3from pathlib import Path4 5import pytest6 7sys.path.insert(0, str(Path(__file__).resolve().parents[2]))8 9import mechanical_refactor_reproduction_utils as rr10from mechanical_refactor_reproduction_utils import (11    Repro,12    _def_span,13    _find_class,14    _find_def,15    _replace_span,16    _slice_span,17    dedent,18    exec_command,19    git_add_and_commit,20    verify_mechanical_refactor,21)22from reproduction_testlib import _apply, _commit, _git, _write  # noqa: F40123 24# --- verify_mechanical_refactor ------------------------------------------------25 26 27def _silence_precommit(monkeypatch) -> None:28    real = rr.exec_command29 30    def fake(cmd: str, cwd=None, check=True):31        if cmd.startswith("pre-commit"):32            return ""33        return real(cmd, cwd=cwd, check=check)34 35    monkeypatch.setattr(rr, "exec_command", fake)36 37 38def test_reproduce_passes_when_transform_matches_target(39    repo: Path, tmp_path: Path, monkeypatch, capsys40) -> None:41    """A transform that recreates the target tree reports PASS and does not exit."""42    _write(repo, **{"src.py": "line1\nline2\nline3\n"})43    base = _commit(repo, "base")44    _write(repo, **{"src.py": None, "a.py": "line1\nline2\n", "b.py": "line3\n"})45    target = _commit(repo, "split")46 47    def transform(root: Path) -> None:48        lines = (root / "src.py").read_text().splitlines(keepends=True)49        (root / "a.py").write_text("".join(lines[0:2]))50        (root / "b.py").write_text("".join(lines[2:3]))51        (root / "src.py").unlink()52        rr.git_add_and_commit("split", cwd=str(root))53 54    monkeypatch.chdir(repo)55    monkeypatch.setattr(rr.tempfile, "mkdtemp", lambda prefix="": str(tmp_path / "wt"))56    _silence_precommit(monkeypatch)57 58    verify_mechanical_refactor(base, target, transform)59    assert "PASS" in capsys.readouterr().out60 61 62def test_reproduce_exits_when_transform_diverges(63    repo: Path, tmp_path: Path, monkeypatch64) -> None:65    """A transform that produces a different tree fails with a non-zero exit."""66    _write(repo, **{"src.py": "line1\nline2\nline3\n"})67    base = _commit(repo, "base")68    _write(repo, **{"src.py": None, "a.py": "line1\nline2\n", "b.py": "line3\n"})69    target = _commit(repo, "split")70 71    def wrong_transform(root: Path) -> None:72        (root / "a.py").write_text("WRONG\n")73        (root / "b.py").write_text("line3\n")74        (root / "src.py").unlink()75        rr.git_add_and_commit("split", cwd=str(root))76 77    monkeypatch.chdir(repo)78    monkeypatch.setattr(rr.tempfile, "mkdtemp", lambda prefix="": str(tmp_path / "wt"))79    _silence_precommit(monkeypatch)80 81    with pytest.raises(SystemExit):82        verify_mechanical_refactor(base, target, wrong_transform)83 84 85def test_reproduce_creates_verify_branch_on_pass(86    repo: Path, tmp_path: Path, monkeypatch, capsys87) -> None:88    """A PASS run leaves a verify-mechanical-<base[:8]> branch in the repo."""89    _write(repo, **{"src.py": "line1\nline2\nline3\n"})90    base = _commit(repo, "base")91    _write(repo, **{"src.py": None, "a.py": "line1\nline2\n", "b.py": "line3\n"})92    target = _commit(repo, "split")93 94    def transform(root: Path) -> None:95        lines = (root / "src.py").read_text().splitlines(keepends=True)96        (root / "a.py").write_text("".join(lines[0:2]))97        (root / "b.py").write_text("".join(lines[2:3]))98        (root / "src.py").unlink()99        rr.git_add_and_commit("split", cwd=str(root))100 101    monkeypatch.chdir(repo)102    monkeypatch.setattr(rr.tempfile, "mkdtemp", lambda prefix="": str(tmp_path / "wt"))103    _silence_precommit(monkeypatch)104 105    verify_mechanical_refactor(base, target, transform)106    assert "PASS" in capsys.readouterr().out107    branch = f"verify-mechanical-{base[:8]}"108    assert _git(repo, "branch", "--list", branch).endswith(branch)109 110 111def _precommit_writes_file(monkeypatch, filename: str, contents: str) -> None:112    real = rr.exec_command113 114    def fake(cmd: str, cwd=None, check=True):115        if cmd.startswith("pre-commit"):116            (Path(cwd) / filename).write_text(contents)117            return ""118        return real(cmd, cwd=cwd, check=check)119 120    monkeypatch.setattr(rr, "exec_command", fake)121 122 123def test_reproduce_commits_pre_commit_fixes_when_tree_left_dirty(124    repo: Path, tmp_path: Path, monkeypatch, capsys125) -> None:126    """When pre-commit reformats and leaves the tree dirty, a 'pre-commit fixes' commit127    is created on top of the transform commit."""128    _write(repo, **{"src.py": "hello\n"})129    base = _commit(repo, "base")130    _write(repo, **{"src.py": "hello world\n", "formatted.py": "auto\n"})131    target = _commit(repo, "edit")132 133    def transform(root: Path) -> None:134        (root / "src.py").write_text("hello world\n")135        rr.git_add_and_commit("transform", cwd=str(root))136 137    monkeypatch.chdir(repo)138    monkeypatch.setattr(rr.tempfile, "mkdtemp", lambda prefix="": str(tmp_path / "wt"))139    _precommit_writes_file(monkeypatch, "formatted.py", "auto\n")140 141    verify_mechanical_refactor(base, target, transform)142    assert "PASS" in capsys.readouterr().out143    branch = f"verify-mechanical-{base[:8]}"144    subjects = _git(repo, "log", "--format=%s", "-2", branch).splitlines()145    assert subjects == ["pre-commit fixes", "transform"]146 147 148# --- Repro.run end-to-end ------------------------------------------------------149 150 151def test_repro_run_passes_on_a_faithful_call_site_lowering(152    repo: Path, monkeypatch, capsys153) -> None:154    """End-to-end: a lowering reproduces the commit byte-for-byte (pre-commit stubbed)."""155    _write(repo, **{"c.py": "r = Old.foo(self.n, 5)\n"})156    base = _commit(repo, "base")157    _write(repo, **{"c.py": "r = self.n.foo(5)\n"})158    target = _commit(repo, "lower the call site")159    monkeypatch.chdir(repo)160    _silence_precommit(monkeypatch)161 162    diff = Repro(base, target).lower_call_sites("foo", "Old", paths=["c.py"]).run()163    assert diff == ""164    assert "PASS" in capsys.readouterr().out165 166 167def test_repro_run_reports_residual_when_a_change_is_bundled(168    repo: Path, monkeypatch, capsys169) -> None:170    """A bundled non-relocation change surfaces as a non-empty residual diff."""171    _write(repo, **{"c.py": "r = Old.foo(self.n, 5)\nUNRELATED = 1\n"})172    base = _commit(repo, "base")173    _write(repo, **{"c.py": "r = self.n.foo(5)\nUNRELATED = 2\n"})174    target = _commit(repo, "lower the call AND change a constant")175    monkeypatch.chdir(repo)176    _silence_precommit(monkeypatch)177 178    diff = Repro(base, target).lower_call_sites("foo", "Old", paths=["c.py"]).run()179    assert "UNRELATED" in diff180    assert "RESIDUAL" in capsys.readouterr().out181