merge.py
python
| 1 | """muse merge — three-way merge a branch into the current branch. |
| 2 | |
| 3 | Algorithm |
| 4 | --------- |
| 5 | 1. Find the merge base (LCA) of HEAD and the target branch. |
| 6 | 2. Delegate conflict detection and manifest reconciliation to the domain plugin. |
| 7 | 3. If clean → apply merged manifest, write new commit, advance HEAD. |
| 8 | 4. If conflicts → write muse-work/ with conflict markers, write |
| 9 | ``.muse/MERGE_STATE.json``, exit non-zero. |
| 10 | """ |
| 11 | from __future__ import annotations |
| 12 | |
| 13 | import datetime |
| 14 | import json |
| 15 | import logging |
| 16 | import pathlib |
| 17 | import shutil |
| 18 | |
| 19 | import typer |
| 20 | |
| 21 | from muse.core.errors import ExitCode |
| 22 | from muse.core.merge_engine import ( |
| 23 | find_merge_base, |
| 24 | write_merge_state, |
| 25 | ) |
| 26 | from muse.core.object_store import restore_object |
| 27 | from muse.core.repo import require_repo |
| 28 | from muse.core.snapshot import compute_commit_id, compute_snapshot_id |
| 29 | from muse.core.store import ( |
| 30 | CommitRecord, |
| 31 | SnapshotRecord, |
| 32 | get_head_commit_id, |
| 33 | get_head_snapshot_manifest, |
| 34 | read_commit, |
| 35 | read_snapshot, |
| 36 | write_commit, |
| 37 | write_snapshot, |
| 38 | ) |
| 39 | from muse.domain import SnapshotManifest, StructuredMergePlugin |
| 40 | from muse.plugins.registry import read_domain, resolve_plugin |
| 41 | |
| 42 | logger = logging.getLogger(__name__) |
| 43 | |
| 44 | app = typer.Typer() |
| 45 | |
| 46 | |
| 47 | def _read_branch(root: pathlib.Path) -> str: |
| 48 | """Return the current branch name by reading ``.muse/HEAD``.""" |
| 49 | head_ref = (root / ".muse" / "HEAD").read_text().strip() |
| 50 | return head_ref.removeprefix("refs/heads/").strip() |
| 51 | |
| 52 | |
| 53 | def _read_repo_id(root: pathlib.Path) -> str: |
| 54 | """Return the repository UUID from ``.muse/repo.json``.""" |
| 55 | return str(json.loads((root / ".muse" / "repo.json").read_text())["repo_id"]) |
| 56 | |
| 57 | |
| 58 | def _restore_from_manifest(root: pathlib.Path, manifest: dict[str, str]) -> None: |
| 59 | """Rebuild ``muse-work/`` to exactly match *manifest*. |
| 60 | |
| 61 | Wipes the existing ``muse-work/`` directory (destructive), recreates it, |
| 62 | and restores each object from the local content-addressed store. All |
| 63 | parent directories for nested paths are created as needed. |
| 64 | |
| 65 | Args: |
| 66 | root: Repository root (parent of ``.muse/``). |
| 67 | manifest: Mapping of workspace-relative POSIX paths to SHA-256 |
| 68 | object IDs to restore. |
| 69 | """ |
| 70 | workdir = root / "muse-work" |
| 71 | if workdir.exists(): |
| 72 | shutil.rmtree(workdir) |
| 73 | workdir.mkdir() |
| 74 | for rel_path, object_id in manifest.items(): |
| 75 | restore_object(root, object_id, workdir / rel_path) |
| 76 | |
| 77 | |
| 78 | @app.callback(invoke_without_command=True) |
| 79 | def merge( |
| 80 | ctx: typer.Context, |
| 81 | branch: str = typer.Argument(..., help="Branch to merge into the current branch."), |
| 82 | no_ff: bool = typer.Option(False, "--no-ff", help="Always create a merge commit, even for fast-forward."), |
| 83 | message: str | None = typer.Option(None, "-m", "--message", help="Override the merge commit message."), |
| 84 | ) -> None: |
| 85 | """Three-way merge a branch into the current branch.""" |
| 86 | root = require_repo() |
| 87 | repo_id = _read_repo_id(root) |
| 88 | current_branch = _read_branch(root) |
| 89 | domain = read_domain(root) |
| 90 | plugin = resolve_plugin(root) |
| 91 | |
| 92 | if branch == current_branch: |
| 93 | typer.echo("❌ Cannot merge a branch into itself.") |
| 94 | raise typer.Exit(code=ExitCode.USER_ERROR) |
| 95 | |
| 96 | ours_commit_id = get_head_commit_id(root, current_branch) |
| 97 | theirs_commit_id = get_head_commit_id(root, branch) |
| 98 | |
| 99 | if theirs_commit_id is None: |
| 100 | typer.echo(f"❌ Branch '{branch}' has no commits.") |
| 101 | raise typer.Exit(code=ExitCode.USER_ERROR) |
| 102 | |
| 103 | if ours_commit_id is None: |
| 104 | typer.echo("❌ Current branch has no commits.") |
| 105 | raise typer.Exit(code=ExitCode.USER_ERROR) |
| 106 | |
| 107 | base_commit_id = find_merge_base(root, ours_commit_id, theirs_commit_id) |
| 108 | |
| 109 | if base_commit_id == theirs_commit_id: |
| 110 | typer.echo("Already up to date.") |
| 111 | return |
| 112 | |
| 113 | if base_commit_id == ours_commit_id and not no_ff: |
| 114 | theirs_commit = read_commit(root, theirs_commit_id) |
| 115 | if theirs_commit: |
| 116 | snapshot = json.loads((root / ".muse" / "snapshots" / f"{theirs_commit.snapshot_id}.json").read_text()) |
| 117 | _restore_from_manifest(root, snapshot["manifest"]) |
| 118 | (root / ".muse" / "refs" / "heads" / current_branch).write_text(theirs_commit_id) |
| 119 | typer.echo(f"Fast-forward to {theirs_commit_id[:8]}") |
| 120 | return |
| 121 | |
| 122 | ours_manifest = get_head_snapshot_manifest(root, repo_id, current_branch) or {} |
| 123 | theirs_manifest = get_head_snapshot_manifest(root, repo_id, branch) or {} |
| 124 | base_manifest: dict[str, str] = {} |
| 125 | if base_commit_id: |
| 126 | base_commit = read_commit(root, base_commit_id) |
| 127 | if base_commit: |
| 128 | base_snap = read_snapshot(root, base_commit.snapshot_id) |
| 129 | if base_snap: |
| 130 | base_manifest = base_snap.manifest |
| 131 | |
| 132 | base_snap_obj = SnapshotManifest(files=base_manifest, domain=domain) |
| 133 | ours_snap_obj = SnapshotManifest(files=ours_manifest, domain=domain) |
| 134 | theirs_snap_obj = SnapshotManifest(files=theirs_manifest, domain=domain) |
| 135 | |
| 136 | # Phase 3: prefer operation-level merge when the plugin supports it. |
| 137 | # Produces finer-grained conflict detection (sub-file / note level). |
| 138 | # Falls back to file-level merge() for plugins without this capability. |
| 139 | if isinstance(plugin, StructuredMergePlugin): |
| 140 | ours_delta = plugin.diff(base_snap_obj, ours_snap_obj, repo_root=root) |
| 141 | theirs_delta = plugin.diff(base_snap_obj, theirs_snap_obj, repo_root=root) |
| 142 | result = plugin.merge_ops( |
| 143 | base_snap_obj, |
| 144 | ours_snap_obj, |
| 145 | theirs_snap_obj, |
| 146 | ours_delta["ops"], |
| 147 | theirs_delta["ops"], |
| 148 | repo_root=root, |
| 149 | ) |
| 150 | logger.debug( |
| 151 | "merge: used operation-level merge (%s); %d conflict(s)", |
| 152 | type(plugin).__name__, |
| 153 | len(result.conflicts), |
| 154 | ) |
| 155 | else: |
| 156 | result = plugin.merge(base_snap_obj, ours_snap_obj, theirs_snap_obj, repo_root=root) |
| 157 | |
| 158 | # Report any .museattributes auto-resolutions. |
| 159 | if result.applied_strategies: |
| 160 | for p, strategy in sorted(result.applied_strategies.items()): |
| 161 | if strategy == "dimension-merge": |
| 162 | dim_detail = result.dimension_reports.get(p, {}) |
| 163 | dim_summary = ", ".join( |
| 164 | f"{d}={v}" for d, v in sorted(dim_detail.items()) |
| 165 | ) |
| 166 | typer.echo(f" ✔ dimension-merge: {p} ({dim_summary})") |
| 167 | elif strategy != "manual": |
| 168 | typer.echo(f" ✔ [{strategy}] {p}") |
| 169 | |
| 170 | if not result.is_clean: |
| 171 | write_merge_state( |
| 172 | root, |
| 173 | base_commit=base_commit_id or "", |
| 174 | ours_commit=ours_commit_id, |
| 175 | theirs_commit=theirs_commit_id, |
| 176 | conflict_paths=result.conflicts, |
| 177 | other_branch=branch, |
| 178 | ) |
| 179 | typer.echo(f"❌ Merge conflict in {len(result.conflicts)} file(s):") |
| 180 | for p in sorted(result.conflicts): |
| 181 | typer.echo(f" CONFLICT (both modified): {p}") |
| 182 | typer.echo('\nFix conflicts and run "muse commit" to complete the merge.') |
| 183 | raise typer.Exit(code=ExitCode.USER_ERROR) |
| 184 | |
| 185 | merged_manifest = result.merged["files"] |
| 186 | _restore_from_manifest(root, merged_manifest) |
| 187 | |
| 188 | snapshot_id = compute_snapshot_id(merged_manifest) |
| 189 | committed_at = datetime.datetime.now(datetime.timezone.utc) |
| 190 | merge_message = message or f"Merge branch '{branch}' into {current_branch}" |
| 191 | commit_id = compute_commit_id( |
| 192 | parent_ids=[ours_commit_id, theirs_commit_id], |
| 193 | snapshot_id=snapshot_id, |
| 194 | message=merge_message, |
| 195 | committed_at_iso=committed_at.isoformat(), |
| 196 | ) |
| 197 | |
| 198 | write_snapshot(root, SnapshotRecord(snapshot_id=snapshot_id, manifest=merged_manifest)) |
| 199 | write_commit(root, CommitRecord( |
| 200 | commit_id=commit_id, |
| 201 | repo_id=repo_id, |
| 202 | branch=current_branch, |
| 203 | snapshot_id=snapshot_id, |
| 204 | message=merge_message, |
| 205 | committed_at=committed_at, |
| 206 | parent_commit_id=ours_commit_id, |
| 207 | parent2_commit_id=theirs_commit_id, |
| 208 | )) |
| 209 | (root / ".muse" / "refs" / "heads" / current_branch).write_text(commit_id) |
| 210 | |
| 211 | typer.echo(f"Merged '{branch}' into '{current_branch}' ({commit_id[:8]})") |