revert.py
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| 1 | """``muse revert`` — create a new commit that undoes a prior commit. |
| 2 | |
| 3 | Revert is the safe undo: instead of rewriting history (as ``muse reset`` |
| 4 | does), revert appends a new commit whose snapshot matches the target |
| 5 | commit's parent snapshot. The branch history stays linear and auditable. |
| 6 | |
| 7 | Usage:: |
| 8 | |
| 9 | muse revert <ref> — revert and commit immediately |
| 10 | muse revert <ref> --no-commit — apply the revert to the working tree only |
| 11 | muse revert <ref> --dry-run — simulate without writing anything |
| 12 | |
| 13 | JSON output (``--format json`` or ``--json``):: |
| 14 | |
| 15 | { |
| 16 | "status": "reverted | applied", |
| 17 | "commit_id": "<sha256> | null", |
| 18 | "branch": "<current-branch>", |
| 19 | "ref": "<ref-as-passed>", |
| 20 | "reverted_commit_id": "<sha256>", |
| 21 | "snapshot_id": "<sha256>", |
| 22 | "message": "<revert-commit-message>", |
| 23 | "no_commit": false, |
| 24 | "dry_run": false |
| 25 | } |
| 26 | |
| 27 | The schema is identical for all paths (normal, ``--no-commit``, |
| 28 | ``--dry-run``); only ``status``, ``commit_id``, ``no_commit``, and |
| 29 | ``dry_run`` vary. |
| 30 | |
| 31 | Exit codes:: |
| 32 | |
| 33 | 0 — success (reverted, applied to workdir, or dry-run) |
| 34 | 1 — ref not found, root commit, invalid format |
| 35 | 3 — internal error (parent commit or snapshot missing) |
| 36 | """ |
| 37 | |
| 38 | from __future__ import annotations |
| 39 | |
| 40 | import argparse |
| 41 | import datetime |
| 42 | import json |
| 43 | import logging |
| 44 | import sys |
| 45 | |
| 46 | from muse.core.errors import ExitCode |
| 47 | from muse.core.reflog import append_reflog |
| 48 | from muse.core.repo import read_repo_id, require_repo |
| 49 | from muse.core.snapshot import compute_commit_id |
| 50 | from muse.core.store import ( |
| 51 | CommitRecord, |
| 52 | get_head_commit_id, |
| 53 | read_commit, |
| 54 | read_current_branch, |
| 55 | read_snapshot, |
| 56 | resolve_commit_ref, |
| 57 | write_branch_ref, |
| 58 | write_commit, |
| 59 | ) |
| 60 | from muse.core.validation import sanitize_display, validate_branch_name |
| 61 | from muse.core.workdir import apply_manifest |
| 62 | from muse.cli.guard import require_clean_workdir |
| 63 | |
| 64 | logger = logging.getLogger(__name__) |
| 65 | |
| 66 | |
| 67 | def register(subparsers: "argparse._SubParsersAction[argparse.ArgumentParser]") -> None: |
| 68 | """Register the ``muse revert`` subcommand and all its flags.""" |
| 69 | parser = subparsers.add_parser( |
| 70 | "revert", |
| 71 | help="Create a new commit that undoes a prior commit.", |
| 72 | description=__doc__, |
| 73 | formatter_class=argparse.RawDescriptionHelpFormatter, |
| 74 | ) |
| 75 | parser.add_argument("ref", help="Commit to revert (ID, HEAD, HEAD~N).") |
| 76 | parser.add_argument( |
| 77 | "-m", "--message", default=None, |
| 78 | help="Override the revert commit message.", |
| 79 | ) |
| 80 | parser.add_argument( |
| 81 | "--no-commit", "-n", action="store_true", dest="no_commit", |
| 82 | help="Apply the revert to the working tree without creating a commit.", |
| 83 | ) |
| 84 | parser.add_argument( |
| 85 | "--force", action="store_true", |
| 86 | help="Proceed even if the working tree has uncommitted changes.", |
| 87 | ) |
| 88 | parser.add_argument( |
| 89 | "--dry-run", action="store_true", dest="dry_run", |
| 90 | help=( |
| 91 | "Simulate the revert without writing anything. " |
| 92 | "Validates the target ref and its parent snapshot." |
| 93 | ), |
| 94 | ) |
| 95 | parser.add_argument( |
| 96 | "--format", "-f", default="text", dest="fmt", |
| 97 | help="Output format: text (default) or json.", |
| 98 | ) |
| 99 | parser.add_argument( |
| 100 | "--json", action="store_const", const="json", dest="fmt", |
| 101 | help="Shorthand for --format json.", |
| 102 | ) |
| 103 | parser.set_defaults(func=run) |
| 104 | |
| 105 | |
| 106 | def run(args: argparse.Namespace) -> None: |
| 107 | """Create a new commit that undoes a prior commit. |
| 108 | |
| 109 | All error messages are written to **stderr**; stdout is reserved for |
| 110 | structured output only. |
| 111 | |
| 112 | Agents should pass ``--format json`` for a stable, machine-readable |
| 113 | result with a consistent schema across all paths:: |
| 114 | |
| 115 | { |
| 116 | "status": "reverted | applied", |
| 117 | "commit_id": "<sha256> | null", |
| 118 | "branch": "<current-branch>", |
| 119 | "ref": "<ref-as-passed>", |
| 120 | "reverted_commit_id": "<sha256>", |
| 121 | "snapshot_id": "<sha256>", |
| 122 | "message": "<revert-commit-message>", |
| 123 | "no_commit": false, |
| 124 | "dry_run": false |
| 125 | } |
| 126 | |
| 127 | Pass ``--dry-run`` to validate the target ref and its parent snapshot |
| 128 | without touching the working tree or creating any commit. |
| 129 | |
| 130 | Pass ``--no-commit`` to apply the revert to the working tree and stage it |
| 131 | for a subsequent ``muse commit``. |
| 132 | |
| 133 | Exit codes:: |
| 134 | |
| 135 | 0 — success (reverted, applied, or dry-run) |
| 136 | 1 — ref not found, root commit, invalid format |
| 137 | 3 — internal error (parent commit or snapshot missing) |
| 138 | """ |
| 139 | ref: str = args.ref |
| 140 | message: str | None = args.message |
| 141 | no_commit: bool = args.no_commit |
| 142 | force: bool = args.force |
| 143 | dry_run: bool = getattr(args, "dry_run", False) |
| 144 | fmt: str = args.fmt |
| 145 | |
| 146 | if fmt not in ("text", "json"): |
| 147 | print( |
| 148 | f"❌ Unknown --format '{sanitize_display(fmt)}'. Choose text or json.", |
| 149 | file=sys.stderr, |
| 150 | ) |
| 151 | raise SystemExit(ExitCode.USER_ERROR) |
| 152 | |
| 153 | root = require_repo() |
| 154 | # Dry-run never touches the working tree. |
| 155 | if not dry_run: |
| 156 | require_clean_workdir(root, "revert", force=force) |
| 157 | repo_id = read_repo_id(root) |
| 158 | branch = read_current_branch(root) |
| 159 | |
| 160 | try: |
| 161 | validate_branch_name(branch) |
| 162 | except ValueError as exc: |
| 163 | print( |
| 164 | f"❌ Current branch name is invalid: {sanitize_display(str(exc))}", |
| 165 | file=sys.stderr, |
| 166 | ) |
| 167 | raise SystemExit(ExitCode.INTERNAL_ERROR) |
| 168 | |
| 169 | target = resolve_commit_ref(root, repo_id, branch, ref) |
| 170 | if target is None: |
| 171 | print( |
| 172 | f"❌ Commit '{sanitize_display(ref)}' not found.", |
| 173 | file=sys.stderr, |
| 174 | ) |
| 175 | raise SystemExit(ExitCode.USER_ERROR) |
| 176 | |
| 177 | if target.parent_commit_id is None: |
| 178 | print( |
| 179 | "❌ Cannot revert the root commit (no parent to restore).", |
| 180 | file=sys.stderr, |
| 181 | ) |
| 182 | raise SystemExit(ExitCode.USER_ERROR) |
| 183 | |
| 184 | parent_commit = read_commit(root, target.parent_commit_id) |
| 185 | if parent_commit is None: |
| 186 | print( |
| 187 | f"❌ Parent commit {target.parent_commit_id[:8]} not found.", |
| 188 | file=sys.stderr, |
| 189 | ) |
| 190 | raise SystemExit(ExitCode.INTERNAL_ERROR) |
| 191 | |
| 192 | target_snapshot = read_snapshot(root, parent_commit.snapshot_id) |
| 193 | if target_snapshot is None: |
| 194 | print( |
| 195 | f"❌ Snapshot {parent_commit.snapshot_id[:8]} not found.", |
| 196 | file=sys.stderr, |
| 197 | ) |
| 198 | raise SystemExit(ExitCode.INTERNAL_ERROR) |
| 199 | |
| 200 | # Sanitize the original commit message before embedding it in the revert |
| 201 | # commit message, which is stored permanently on disk. |
| 202 | safe_original_message = sanitize_display(target.message.splitlines()[0]) |
| 203 | revert_message = message or f'Revert "{safe_original_message}"' |
| 204 | |
| 205 | # The parent snapshot is already content-addressed in the object store — |
| 206 | # reuse its snapshot_id directly rather than re-scanning the workdir. |
| 207 | snapshot_id = parent_commit.snapshot_id |
| 208 | |
| 209 | # Dry-run: validate succeeded — report what would happen and exit. |
| 210 | if dry_run: |
| 211 | if fmt == "json": |
| 212 | print(json.dumps({ |
| 213 | "status": "reverted", |
| 214 | "commit_id": None, |
| 215 | "branch": branch, |
| 216 | "ref": ref, |
| 217 | "reverted_commit_id": target.commit_id, |
| 218 | "snapshot_id": snapshot_id, |
| 219 | "message": revert_message, |
| 220 | "no_commit": no_commit, |
| 221 | "dry_run": True, |
| 222 | })) |
| 223 | else: |
| 224 | print( |
| 225 | f"[dry-run] Would revert '{sanitize_display(ref)}' " |
| 226 | f"({target.commit_id[:8]}) on '{sanitize_display(branch)}'" |
| 227 | ) |
| 228 | return |
| 229 | |
| 230 | head_commit_id = get_head_commit_id(root, branch) |
| 231 | |
| 232 | if no_commit: |
| 233 | apply_manifest(root, target_snapshot.manifest) |
| 234 | if fmt == "json": |
| 235 | print(json.dumps({ |
| 236 | "status": "applied", |
| 237 | "commit_id": None, |
| 238 | "branch": branch, |
| 239 | "ref": ref, |
| 240 | "reverted_commit_id": target.commit_id, |
| 241 | "snapshot_id": snapshot_id, |
| 242 | "message": revert_message, |
| 243 | "no_commit": True, |
| 244 | "dry_run": False, |
| 245 | })) |
| 246 | else: |
| 247 | print( |
| 248 | f"Revert of {target.commit_id[:8]} applied to working tree. " |
| 249 | f"Run 'muse commit' to record." |
| 250 | ) |
| 251 | return |
| 252 | |
| 253 | # Correct write ordering for atomicity: |
| 254 | # 1. Compute commit record (all data validated above — no I/O failures possible here). |
| 255 | # 2. write_commit (idempotent — crash here leaves the workdir unchanged). |
| 256 | # 3. apply_manifest (workdir is modified only after the commit is durably stored). |
| 257 | # 4. write_branch_ref (branch pointer advances last — visible to others only when complete). |
| 258 | # 5. append_reflog (non-critical audit trail — never blocks success). |
| 259 | committed_at = datetime.datetime.now(datetime.timezone.utc) |
| 260 | commit_id = compute_commit_id( |
| 261 | parent_ids=[head_commit_id] if head_commit_id else [], |
| 262 | snapshot_id=snapshot_id, |
| 263 | message=revert_message, |
| 264 | committed_at_iso=committed_at.isoformat(), |
| 265 | ) |
| 266 | |
| 267 | write_commit(root, CommitRecord( |
| 268 | commit_id=commit_id, |
| 269 | repo_id=repo_id, |
| 270 | branch=branch, |
| 271 | snapshot_id=snapshot_id, |
| 272 | message=revert_message, |
| 273 | committed_at=committed_at, |
| 274 | parent_commit_id=head_commit_id, |
| 275 | )) |
| 276 | apply_manifest(root, target_snapshot.manifest) |
| 277 | write_branch_ref(root, branch, commit_id) |
| 278 | append_reflog( |
| 279 | root, branch, old_id=head_commit_id, new_id=commit_id, |
| 280 | author="user", |
| 281 | operation=f"revert: {sanitize_display(ref)} → {commit_id[:12]}", |
| 282 | ) |
| 283 | |
| 284 | if fmt == "json": |
| 285 | print(json.dumps({ |
| 286 | "status": "reverted", |
| 287 | "commit_id": commit_id, |
| 288 | "branch": branch, |
| 289 | "ref": ref, |
| 290 | "reverted_commit_id": target.commit_id, |
| 291 | "snapshot_id": snapshot_id, |
| 292 | "message": revert_message, |
| 293 | "no_commit": False, |
| 294 | "dry_run": False, |
| 295 | })) |
| 296 | else: |
| 297 | print( |
| 298 | f"[{sanitize_display(branch)} {commit_id[:8]}] " |
| 299 | f"{sanitize_display(revert_message)}" |
| 300 | ) |