cohen_transform.py
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| 1 | """cohen_transform.py — Three-way line-level merge with Manyana-style action labels. |
| 2 | |
| 3 | Named in honour of Bram Cohen (creator of BitTorrent, inventor of the Manyana |
| 4 | CRDT weave algorithm), whose conflict-presentation insight is the direct |
| 5 | inspiration for this module. |
| 6 | |
| 7 | The Cohen Transform observation |
| 8 | -------------------------------- |
| 9 | Traditional VCS tools display a merge conflict as two opaque blobs — "ours" |
| 10 | and "theirs" — and leave the user to reconstruct *what each side actually did*. |
| 11 | Bram Cohen's Manyana project labels every conflict hunk with the action and the |
| 12 | side that performed it: |
| 13 | |
| 14 | <<<<<<< ours [deleted] |
| 15 | def calculate(x): |
| 16 | a = x * 2 |
| 17 | ||||||| base |
| 18 | def calculate(x): |
| 19 | a = x * 2 |
| 20 | b = a + 1 |
| 21 | return b |
| 22 | ======= theirs [inserted] |
| 23 | logger.debug(f"a={a}") |
| 24 | >>>>>>> end conflict |
| 25 | |
| 26 | You can immediately see: ours deleted a function, theirs inserted a line into |
| 27 | the middle of it. That is a structurally different level of information from |
| 28 | two unlabelled blobs. |
| 29 | |
| 30 | Public API |
| 31 | ---------- |
| 32 | three_way_merge_lines(base, ours, theirs, ...) |
| 33 | Core merge function. Returns (merged_lines, has_conflict). |
| 34 | |
| 35 | MergeRegion |
| 36 | Dataclass representing one segment of the three-way analysis. |
| 37 | |
| 38 | classify_action(base_lines, other_lines) |
| 39 | Classify a change as 'inserted', 'deleted', or 'modified'. |
| 40 | |
| 41 | annotate_hunk_action(hunk_lines, side_label) |
| 42 | Post-process a unified-diff hunk list, rewriting @@ headers with |
| 43 | action labels for use in ``muse diff --conflict`` output. |
| 44 | |
| 45 | format_conflict_diff(path, root, base_manifest, ours_manifest, theirs_manifest, |
| 46 | read_object_fn, *, use_color, ours_label, theirs_label) |
| 47 | Render a Manyana-style two-sided labeled diff for a single conflicting file. |
| 48 | Used by ``muse diff --conflict``. |
| 49 | |
| 50 | References |
| 51 | ---------- |
| 52 | - Bram Cohen, Manyana: https://github.com/bramcohen/manyana |
| 53 | - Bram Cohen's blog: https://bramcohen.com/ |
| 54 | """ |
| 55 | |
| 56 | from __future__ import annotations |
| 57 | |
| 58 | import difflib |
| 59 | import pathlib |
| 60 | from dataclasses import dataclass, field |
| 61 | from typing import Callable, Sequence |
| 62 | |
| 63 | # ── Public constants ────────────────────────────────────────────────────────── |
| 64 | |
| 65 | #: Separator used between the two sides of a conflict-aware diff header. |
| 66 | CONFLICT_SEPARATOR = "═" * 54 |
| 67 | |
| 68 | #: Marker tokens — match git's diff3 style so editors recognise them, but |
| 69 | #: the action label suffix (e.g. ``[deleted]``) is the Cohen extension. |
| 70 | _MARKER_OURS_PREFIX = "<<<<<<< " |
| 71 | _MARKER_BASE = "||||||| base" |
| 72 | _MARKER_SEP_PREFIX = "======= " |
| 73 | _MARKER_END = ">>>>>>> end conflict" |
| 74 | |
| 75 | |
| 76 | # ── Data classes ────────────────────────────────────────────────────────────── |
| 77 | |
| 78 | |
| 79 | @dataclass |
| 80 | class MergeRegion: |
| 81 | """One segment of a three-way merge analysis. |
| 82 | |
| 83 | Attributes: |
| 84 | kind: |
| 85 | ``'stable'`` — identical in all three versions; output base. |
| 86 | ``'ours_only'`` — only ours changed from base; output ours. |
| 87 | ``'theirs_only'`` — only theirs changed from base; output theirs. |
| 88 | ``'both_same'`` — both sides made the same change; output either. |
| 89 | ``'conflict'`` — both sides changed differently; needs markers. |
| 90 | base_lines: Lines from the common ancestor for this segment. |
| 91 | ours_lines: Lines from the ours version for this segment. |
| 92 | theirs_lines: Lines from the theirs version for this segment. |
| 93 | """ |
| 94 | |
| 95 | kind: str |
| 96 | base_lines: list[str] = field(default_factory=list) |
| 97 | ours_lines: list[str] = field(default_factory=list) |
| 98 | theirs_lines: list[str] = field(default_factory=list) |
| 99 | |
| 100 | |
| 101 | # ── Core algorithm ──────────────────────────────────────────────────────────── |
| 102 | |
| 103 | |
| 104 | def _find_sync_regions( |
| 105 | base: Sequence[str], |
| 106 | ours: Sequence[str], |
| 107 | theirs: Sequence[str], |
| 108 | ) -> list[tuple[int, int, int, int, int, int]]: |
| 109 | """Return maximal regions identical in all three sequences. |
| 110 | |
| 111 | Each entry is ``(base_s, base_e, ours_s, ours_e, theirs_s, theirs_e)`` |
| 112 | representing a contiguous block where |
| 113 | ``base[base_s:base_e] == ours[ours_s:ours_e] == theirs[theirs_s:theirs_e]``. |
| 114 | |
| 115 | The algorithm finds base positions matched in BOTH ``base→ours`` and |
| 116 | ``base→theirs`` LCS runs, then groups them into maximal consecutive |
| 117 | triples (consecutive in base, ours, *and* theirs simultaneously). |
| 118 | """ |
| 119 | sm_a = difflib.SequenceMatcher(None, base, ours, autojunk=False) |
| 120 | sm_b = difflib.SequenceMatcher(None, base, theirs, autojunk=False) |
| 121 | |
| 122 | a_map: dict[int, int] = {} # base_pos → ours_pos |
| 123 | b_map: dict[int, int] = {} # base_pos → theirs_pos |
| 124 | |
| 125 | for bi, ai, n in sm_a.get_matching_blocks(): |
| 126 | for k in range(n): |
| 127 | a_map[bi + k] = ai + k |
| 128 | |
| 129 | for bi, ti, n in sm_b.get_matching_blocks(): |
| 130 | for k in range(n): |
| 131 | b_map[bi + k] = ti + k |
| 132 | |
| 133 | stable = sorted(set(a_map) & set(b_map)) |
| 134 | if not stable: |
| 135 | return [] |
| 136 | |
| 137 | sync_regions: list[tuple[int, int, int, int, int, int]] = [] |
| 138 | run_bp = run_ap = run_tp = -1 |
| 139 | prev_bp = prev_ap = prev_tp = -1 |
| 140 | |
| 141 | for bp in stable: |
| 142 | ap = a_map[bp] |
| 143 | tp = b_map[bp] |
| 144 | |
| 145 | if bp == prev_bp + 1 and ap == prev_ap + 1 and tp == prev_tp + 1: |
| 146 | # Extend current run. |
| 147 | prev_bp, prev_ap, prev_tp = bp, ap, tp |
| 148 | else: |
| 149 | # Flush previous run (if any) and start a new one. |
| 150 | if run_bp >= 0: |
| 151 | sync_regions.append(( |
| 152 | run_bp, prev_bp + 1, |
| 153 | run_ap, prev_ap + 1, |
| 154 | run_tp, prev_tp + 1, |
| 155 | )) |
| 156 | run_bp, run_ap, run_tp = bp, ap, tp |
| 157 | prev_bp, prev_ap, prev_tp = bp, ap, tp |
| 158 | |
| 159 | # Flush final run. |
| 160 | if run_bp >= 0: |
| 161 | sync_regions.append(( |
| 162 | run_bp, prev_bp + 1, |
| 163 | run_ap, prev_ap + 1, |
| 164 | run_tp, prev_tp + 1, |
| 165 | )) |
| 166 | |
| 167 | return sync_regions |
| 168 | |
| 169 | |
| 170 | def compute_regions( |
| 171 | base: Sequence[str], |
| 172 | ours: Sequence[str], |
| 173 | theirs: Sequence[str], |
| 174 | ) -> list[MergeRegion]: |
| 175 | """Decompose three sequences into a list of :class:`MergeRegion` objects. |
| 176 | |
| 177 | Uses the sync-region algorithm: finds maximal blocks identical in all |
| 178 | three sequences (the "stable skeleton"), then classifies each gap between |
| 179 | stable blocks as one of: |
| 180 | |
| 181 | - ``ours_only`` — only ours changed from base. |
| 182 | - ``theirs_only`` — only theirs changed from base. |
| 183 | - ``both_same`` — both changed to the same content (clean). |
| 184 | - ``conflict`` — both changed to different content. |
| 185 | |
| 186 | Handles pure insertions (both sides insert different content at the same |
| 187 | base position) as conflicts with an empty base section. |
| 188 | |
| 189 | Args: |
| 190 | base: Common ancestor lines (each ending with ``\\n`` or empty). |
| 191 | ours: Working-tree / our-branch lines. |
| 192 | theirs: Target-branch / their-branch lines. |
| 193 | |
| 194 | Returns: |
| 195 | Ordered list of :class:`MergeRegion` objects covering the entire |
| 196 | three-way merge. |
| 197 | """ |
| 198 | base = list(base) |
| 199 | ours = list(ours) |
| 200 | theirs = list(theirs) |
| 201 | |
| 202 | sync_regions = _find_sync_regions(base, ours, theirs) |
| 203 | |
| 204 | # Sentinel at each end so the loop below handles the leading and trailing |
| 205 | # unstable regions uniformly without special-casing. |
| 206 | sentinels: list[tuple[int, int, int, int, int, int]] = [ |
| 207 | (0, 0, 0, 0, 0, 0), |
| 208 | *sync_regions, |
| 209 | (len(base), len(base), len(ours), len(ours), len(theirs), len(theirs)), |
| 210 | ] |
| 211 | |
| 212 | regions: list[MergeRegion] = [] |
| 213 | |
| 214 | for idx in range(len(sentinels) - 1): |
| 215 | cur = sentinels[idx] |
| 216 | nxt = sentinels[idx + 1] |
| 217 | |
| 218 | # ── Stable block (the sync region itself) ───────────────────────── |
| 219 | bs, be, as_, ae, ts, te = cur |
| 220 | if idx > 0 and be > bs: |
| 221 | regions.append(MergeRegion( |
| 222 | kind="stable", |
| 223 | base_lines=list(base[bs:be]), |
| 224 | ours_lines=list(ours[as_:ae]), |
| 225 | theirs_lines=list(theirs[ts:te]), |
| 226 | )) |
| 227 | |
| 228 | # ── Unstable gap between this sync region and the next ──────────── |
| 229 | nbs, nbe, nas, nae, nts, nte = nxt |
| 230 | b_chunk = list(base[be:nbs]) |
| 231 | a_chunk = list(ours[ae:nas]) |
| 232 | t_chunk = list(theirs[te:nts]) |
| 233 | |
| 234 | if not b_chunk and not a_chunk and not t_chunk: |
| 235 | continue |
| 236 | |
| 237 | if a_chunk == b_chunk and t_chunk == b_chunk: |
| 238 | # All three identical — degenerate stable region (shouldn't |
| 239 | # normally occur given sync detection, but guard it). |
| 240 | regions.append(MergeRegion("stable", b_chunk, a_chunk, t_chunk)) |
| 241 | elif a_chunk == b_chunk: |
| 242 | # Only theirs changed. |
| 243 | regions.append(MergeRegion("theirs_only", b_chunk, b_chunk, t_chunk)) |
| 244 | elif t_chunk == b_chunk: |
| 245 | # Only ours changed. |
| 246 | regions.append(MergeRegion("ours_only", b_chunk, a_chunk, b_chunk)) |
| 247 | elif a_chunk == t_chunk: |
| 248 | # Both sides made the same change — clean (take either). |
| 249 | regions.append(MergeRegion("both_same", b_chunk, a_chunk, t_chunk)) |
| 250 | else: |
| 251 | # True conflict — both sides changed differently. |
| 252 | regions.append(MergeRegion("conflict", b_chunk, a_chunk, t_chunk)) |
| 253 | |
| 254 | return regions |
| 255 | |
| 256 | |
| 257 | # ── Action classification ───────────────────────────────────────────────────── |
| 258 | |
| 259 | |
| 260 | def classify_action(base_lines: list[str], other_lines: list[str]) -> str: |
| 261 | """Classify the action performed from *base_lines* to *other_lines*. |
| 262 | |
| 263 | Returns one of: |
| 264 | - ``'inserted'`` — *other_lines* is non-empty, *base_lines* is empty. |
| 265 | - ``'deleted'`` — *base_lines* is non-empty, *other_lines* is empty. |
| 266 | - ``'modified'`` — both are non-empty but differ. |
| 267 | |
| 268 | Used to annotate conflict markers with the Cohen-transform action label, |
| 269 | e.g. ``<<<<<<< ours [deleted]``. |
| 270 | """ |
| 271 | if not base_lines and other_lines: |
| 272 | return "inserted" |
| 273 | if base_lines and not other_lines: |
| 274 | return "deleted" |
| 275 | return "modified" |
| 276 | |
| 277 | |
| 278 | def annotate_hunk_action(hunk_lines: list[str], side_label: str) -> list[str]: |
| 279 | """Rewrite ``@@`` hunk headers with a Manyana-style action annotation. |
| 280 | |
| 281 | Scans the ``+``/``-`` lines in each hunk to classify the dominant action |
| 282 | on *side_label* (``'ours'`` or ``'theirs'``), then rewrites each ``@@`` |
| 283 | header line from:: |
| 284 | |
| 285 | @@ -12,4 +12,4 @@ |
| 286 | |
| 287 | to:: |
| 288 | |
| 289 | @@ -12,4 +12,4 @@ [ours: deleted] |
| 290 | @@ -12,4 +12,4 @@ [theirs: inserted] |
| 291 | @@ -12,4 +12,4 @@ [ours: modified] |
| 292 | |
| 293 | This is the direct translation of Bram Cohen's ``begin deleted left`` / |
| 294 | ``begin added right`` labeling into unified-diff format. |
| 295 | |
| 296 | Args: |
| 297 | hunk_lines: Lines produced by :func:`difflib.unified_diff`, including |
| 298 | the ``---``/``+++`` header and all ``@@`` blocks. |
| 299 | side_label: Human-readable side identifier, e.g. ``'ours'`` or |
| 300 | ``'theirs'``. |
| 301 | |
| 302 | Returns: |
| 303 | Annotated copy of *hunk_lines* with ``@@`` lines rewritten. |
| 304 | """ |
| 305 | result: list[str] = [] |
| 306 | # Collect lines in the current @@ block to classify when we see the next @@. |
| 307 | current_hunk_body: list[str] = [] |
| 308 | pending_at: str | None = None # the @@ line waiting to be annotated |
| 309 | |
| 310 | def _flush(body: list[str]) -> str: |
| 311 | """Classify and return the annotated @@ line.""" |
| 312 | assert pending_at is not None |
| 313 | adds = sum(1 for ln in body if ln.startswith("+") and not ln.startswith("+++")) |
| 314 | dels = sum(1 for ln in body if ln.startswith("-") and not ln.startswith("---")) |
| 315 | if adds > 0 and dels == 0: |
| 316 | action = "inserted" |
| 317 | elif dels > 0 and adds == 0: |
| 318 | action = "deleted" |
| 319 | else: |
| 320 | action = "modified" |
| 321 | base_at = pending_at.rstrip() |
| 322 | # Remove any trailing existing annotation before appending a new one. |
| 323 | if " [" in base_at: |
| 324 | base_at = base_at[: base_at.rfind(" [")] |
| 325 | return f"{base_at} [{side_label}: {action}]" |
| 326 | |
| 327 | for line in hunk_lines: |
| 328 | if line.startswith("@@"): |
| 329 | if pending_at is not None: |
| 330 | result.append(_flush(current_hunk_body)) |
| 331 | result.extend(current_hunk_body) |
| 332 | current_hunk_body = [] |
| 333 | pending_at = line |
| 334 | elif pending_at is not None: |
| 335 | current_hunk_body.append(line) |
| 336 | else: |
| 337 | result.append(line) |
| 338 | |
| 339 | # Flush the final hunk. |
| 340 | if pending_at is not None: |
| 341 | result.append(_flush(current_hunk_body)) |
| 342 | result.extend(current_hunk_body) |
| 343 | |
| 344 | return result |
| 345 | |
| 346 | |
| 347 | # ── High-level merge function ───────────────────────────────────────────────── |
| 348 | |
| 349 | |
| 350 | def three_way_merge_lines( |
| 351 | base: Sequence[str], |
| 352 | ours: Sequence[str], |
| 353 | theirs: Sequence[str], |
| 354 | *, |
| 355 | label_ours: str = "ours", |
| 356 | label_base: str = "base", |
| 357 | label_theirs: str = "theirs", |
| 358 | ) -> tuple[list[str], bool]: |
| 359 | """Three-way line merge with Manyana-style labeled conflict markers. |
| 360 | |
| 361 | Implements the Cohen Transform: conflict markers include an action label |
| 362 | (``[inserted]``, ``[deleted]``, or ``[modified]``) so the reader |
| 363 | immediately sees *what each side did*, not just *that they conflicted*. |
| 364 | |
| 365 | Marker format (diff3 style with Cohen extensions):: |
| 366 | |
| 367 | <<<<<<< ours [deleted] |
| 368 | [lines from ours — what ours changed base to] |
| 369 | ||||||| base |
| 370 | [lines from common ancestor — the original context] |
| 371 | ======= theirs [inserted] |
| 372 | [lines from theirs — what theirs changed base to] |
| 373 | >>>>>>> end conflict |
| 374 | |
| 375 | The ``||||||| base`` section is always included (diff3 style) because it |
| 376 | gives both humans and agents the context needed to understand *why* each |
| 377 | side made its change. |
| 378 | |
| 379 | Clean merge rules: |
| 380 | - Stable (no change on either side): output base unchanged. |
| 381 | - Ours-only change: output ours version. |
| 382 | - Theirs-only change: output theirs version. |
| 383 | - Both changed to the same content: output that content once. |
| 384 | - Both changed differently: emit conflict markers. |
| 385 | |
| 386 | Args: |
| 387 | base: Lines from the common ancestor. |
| 388 | ours: Lines from our version (working tree or our branch). |
| 389 | theirs: Lines from their version (target branch). |
| 390 | label_ours: Label shown in the ``<<<<<<<`` marker. Defaults to |
| 391 | ``'ours'``. |
| 392 | label_base: Label shown in the ``|||||||`` marker. Defaults to |
| 393 | ``'base'``. |
| 394 | label_theirs: Label shown in the ``=======`` marker. Defaults to |
| 395 | ``'theirs'``. |
| 396 | |
| 397 | Returns: |
| 398 | A ``(merged_lines, has_conflict)`` tuple. *merged_lines* is the |
| 399 | fully merged sequence; *has_conflict* is ``True`` when at least one |
| 400 | conflict block was written. |
| 401 | """ |
| 402 | regions = compute_regions(base, ours, theirs) |
| 403 | merged: list[str] = [] |
| 404 | has_conflict = False |
| 405 | |
| 406 | for region in regions: |
| 407 | if region.kind == "stable": |
| 408 | merged.extend(region.base_lines) |
| 409 | |
| 410 | elif region.kind == "ours_only": |
| 411 | merged.extend(region.ours_lines) |
| 412 | |
| 413 | elif region.kind == "theirs_only": |
| 414 | merged.extend(region.theirs_lines) |
| 415 | |
| 416 | elif region.kind == "both_same": |
| 417 | merged.extend(region.ours_lines) |
| 418 | |
| 419 | else: # conflict |
| 420 | has_conflict = True |
| 421 | ours_action = classify_action(region.base_lines, region.ours_lines) |
| 422 | theirs_action = classify_action(region.base_lines, region.theirs_lines) |
| 423 | |
| 424 | merged.append(f"{_MARKER_OURS_PREFIX}{label_ours} [{ours_action}]\n") |
| 425 | merged.extend(region.ours_lines) |
| 426 | merged.append(f"||||||| {label_base}\n") |
| 427 | merged.extend(region.base_lines) |
| 428 | merged.append(f"{_MARKER_SEP_PREFIX}{label_theirs} [{theirs_action}]\n") |
| 429 | merged.extend(region.theirs_lines) |
| 430 | merged.append(f"{_MARKER_END}\n") |
| 431 | |
| 432 | return merged, has_conflict |
| 433 | |
| 434 | |
| 435 | # ── Conflict-diff renderer (for muse diff --conflict) ──────────────────────── |
| 436 | |
| 437 | |
| 438 | def format_conflict_diff( |
| 439 | path: str, |
| 440 | root: pathlib.Path, |
| 441 | base_manifest: dict[str, str], |
| 442 | ours_manifest: dict[str, str], |
| 443 | theirs_manifest: dict[str, str], |
| 444 | read_object_fn: Callable[[pathlib.Path, str], bytes | None], |
| 445 | *, |
| 446 | use_color: bool = False, |
| 447 | ours_label: str = "ours", |
| 448 | theirs_label: str = "theirs", |
| 449 | ) -> list[str]: |
| 450 | """Render a labeled two-sided diff for a single conflicting file. |
| 451 | |
| 452 | Produces a Cohen-transform conflict view: two separate unified diffs |
| 453 | (``base→ours`` and ``base→theirs``), each with hunk headers annotated |
| 454 | with the action performed by that side. This replaces the opaque |
| 455 | ``<<<<<<< / ======= / >>>>>>>`` blob with a clear narrative of *what |
| 456 | each side did*. |
| 457 | |
| 458 | Example output:: |
| 459 | |
| 460 | ══════════════════════════════════════════════════════ |
| 461 | CONFLICT src/utils.py |
| 462 | ══════════════════════════════════════════════════════ |
| 463 | [ours] what ours changed from base |
| 464 | --- base/src/utils.py |
| 465 | +++ ours/src/utils.py |
| 466 | @@ -12,4 +12,4 @@ [ours: deleted] |
| 467 | - def calculate(x): |
| 468 | - return x * 2 |
| 469 | + def compute(x): |
| 470 | + return x * 3 |
| 471 | |
| 472 | [theirs] what theirs changed from base |
| 473 | --- base/src/utils.py |
| 474 | +++ theirs/src/utils.py |
| 475 | @@ -12,4 +12,4 @@ [theirs: modified] |
| 476 | def calculate(x): |
| 477 | - return x * 2 |
| 478 | + return x * 4 |
| 479 | |
| 480 | Args: |
| 481 | path: Workspace-relative POSIX path of the conflicting file. |
| 482 | root: Repository root (used to read objects from the store). |
| 483 | base_manifest: Manifest of the merge-base commit. |
| 484 | ours_manifest: Manifest of our branch at merge time. |
| 485 | theirs_manifest: Manifest of their branch. |
| 486 | read_object_fn: Callable ``(root, object_id) → bytes | None``. |
| 487 | use_color: When ``True``, emit ANSI colour escapes. |
| 488 | ours_label: Human-readable label for the ours side (e.g. the |
| 489 | branch name). |
| 490 | theirs_label: Human-readable label for the theirs side. |
| 491 | |
| 492 | Returns: |
| 493 | A list of text lines (each *without* a trailing newline) ready to |
| 494 | print. Returns an empty list when no diff exists for this path. |
| 495 | """ |
| 496 | def _read_lines(manifest: dict[str, str], fallback_disk: bool = False) -> list[str]: |
| 497 | oid = manifest.get(path) |
| 498 | if oid: |
| 499 | raw = read_object_fn(root, oid) |
| 500 | if raw is not None: |
| 501 | text = raw.decode("utf-8", errors="replace") |
| 502 | return text.splitlines(keepends=True) |
| 503 | if fallback_disk: |
| 504 | disk = root / path |
| 505 | if disk.is_file(): |
| 506 | return disk.read_text(encoding="utf-8", errors="replace").splitlines(keepends=True) |
| 507 | return [] |
| 508 | |
| 509 | safe_path = path.replace("\x1b", "?") # sanitize ANSI injection |
| 510 | base_lines = _read_lines(base_manifest) |
| 511 | ours_lines = _read_lines(ours_manifest, fallback_disk=True) |
| 512 | theirs_lines = _read_lines(theirs_manifest) |
| 513 | |
| 514 | # ── ANSI colour helpers ─────────────────────────────────────────────────── |
| 515 | def _c(code: str, text: str) -> str: |
| 516 | return f"\x1b[{code}m{text}\x1b[0m" if use_color else text |
| 517 | |
| 518 | def _bold(t: str) -> str: |
| 519 | return _c("1", t) |
| 520 | |
| 521 | def _cyan(t: str) -> str: |
| 522 | return _c("36", t) |
| 523 | |
| 524 | def _green(t: str) -> str: |
| 525 | return _c("32", t) |
| 526 | |
| 527 | def _red(t: str) -> str: |
| 528 | return _c("31", t) |
| 529 | |
| 530 | def _yellow(t: str) -> str: |
| 531 | return _c("33", t) |
| 532 | |
| 533 | # ── Header ──────────────────────────────────────────────────────────────── |
| 534 | output: list[str] = [] |
| 535 | output.append(_bold(CONFLICT_SEPARATOR)) |
| 536 | output.append(_bold(f"CONFLICT {safe_path}")) |
| 537 | output.append(_bold(CONFLICT_SEPARATOR)) |
| 538 | |
| 539 | # ── Ours diff (base → ours) ─────────────────────────────────────────────── |
| 540 | ours_hunks = list(difflib.unified_diff( |
| 541 | base_lines, ours_lines, |
| 542 | fromfile=f"base/{safe_path}", |
| 543 | tofile=f"{ours_label}/{safe_path}", |
| 544 | lineterm="", |
| 545 | )) |
| 546 | annotated_ours = annotate_hunk_action(ours_hunks, ours_label) |
| 547 | |
| 548 | output.append("") |
| 549 | output.append(_yellow(f"[{ours_label}] what {ours_label} changed from base")) |
| 550 | if annotated_ours: |
| 551 | for line in annotated_ours: |
| 552 | if line.startswith("---") or line.startswith("+++"): |
| 553 | output.append(_bold(line)) |
| 554 | elif line.startswith("@@"): |
| 555 | output.append(_cyan(line)) |
| 556 | elif line.startswith("+"): |
| 557 | output.append(_green(line)) |
| 558 | elif line.startswith("-"): |
| 559 | output.append(_red(line)) |
| 560 | else: |
| 561 | output.append(line) |
| 562 | else: |
| 563 | output.append(" (no changes from base on this side)") |
| 564 | |
| 565 | # ── Theirs diff (base → theirs) ─────────────────────────────────────────── |
| 566 | theirs_hunks = list(difflib.unified_diff( |
| 567 | base_lines, theirs_lines, |
| 568 | fromfile=f"base/{safe_path}", |
| 569 | tofile=f"{theirs_label}/{safe_path}", |
| 570 | lineterm="", |
| 571 | )) |
| 572 | annotated_theirs = annotate_hunk_action(theirs_hunks, theirs_label) |
| 573 | |
| 574 | output.append("") |
| 575 | output.append(_yellow(f"[{theirs_label}] what {theirs_label} changed from base")) |
| 576 | if annotated_theirs: |
| 577 | for line in annotated_theirs: |
| 578 | if line.startswith("---") or line.startswith("+++"): |
| 579 | output.append(_bold(line)) |
| 580 | elif line.startswith("@@"): |
| 581 | output.append(_cyan(line)) |
| 582 | elif line.startswith("+"): |
| 583 | output.append(_green(line)) |
| 584 | elif line.startswith("-"): |
| 585 | output.append(_red(line)) |
| 586 | else: |
| 587 | output.append(line) |
| 588 | else: |
| 589 | output.append(" (no changes from base on this side)") |
| 590 | |
| 591 | output.append("") |
| 592 | return output |