HOTSPOT-SPLIT 2/2: per-feature fixture groups and regen steps; sorted .gitattributes

[thejackshelton]

HOTSPOT-SPLIT 2/2 (parity corpus and regen chain). Feature PRs no longer edit the same lines when they register fixture groups or regen steps: each feature owns its own file, and the central list has one line per feature, sorted by id. This lands on master alone, independent of 1/2. The migration note is at the end.

What changed

• Fixture groups (packages/parity/src/fixtures.ts):
  • GROUPS has one line per group, sorted by id, and the imports are sorted.
  • LEGACY_RUN_ORDER freezes the run order of today's 21 groups. Groups added later run after them, in id order.
  • FIXTURE_GROUPS and FIXTURES are unchanged.
• Regen steps (scripts/regen.ts):
  • The legacy STEPS and MANUAL entries stay in regen.ts. A feature puts its steps, extra outputs for existing steps, and MANUAL entries in scripts/regen-steps/<feature>.ts.
  • REGEN_FEATURES has one line per feature, sorted. placeSteps puts each feature step after the step it names, in feature id order, and throws on an unknown step.
  • Empty files exist for the in-flight lanes: bg2, ovfl, pnt1, pnt2, tdec, txt1a and txt2.
  • Step, pnpm(), FIXTURES, FONTS and ENGINE_SOURCES moved to scripts/regen-steps/step.ts. STEPS and MANUAL are unchanged.
• .gitattributes: sorted. The patterns and the attribute are the same, and git ls-files ':(attr:merge=dragon-generated)' lists the same files.
• Duplicate checks: packages/parity/test/registry-claims.test.ts fails when two groups claim a fixture id, or when a step name, output glob or MANUAL command is claimed twice. It also fails when a central list or its imports are unsorted or a feature file is unregistered, and it covers placeSteps ordering and its errors.

Values unchanged

Before regen, I dumped STEPS (with each verdict function's type), MANUAL, MERGE_BY_HAND, FIXTURE_GROUPS and FIXTURES from origin/master and from this branch. The two dumps are byte-identical.

Tests changed (intent kept)

• regen.test.ts, ".gitattributes lists exactly the regen steps' outputs": it now compares sorted lists and requires the file to be sorted, so features add lines in different places. Exactness is unchanged.
• values.test.ts, "is the last legacy group before states": it now checks values and states at the end of LEGACY_RUN_ORDER instead of the end of the whole list, because groups added after the split run after them. The intent (values is the last group before states) is kept.

Verification

• pnpm regen --force: exit 0, and git status is clean afterwards, so every generated output is byte-identical.
• pnpm typecheck: pass.
• pnpm test (full suite): 183 of 184 files passed. planted-swift.test timed out under load (900 s) and passes when rerun alone.
• Run on base ed58eae (origin/master).

Hot spots, measured

I replayed every merge commit on origin/master with git merge-tree --write-tree (376 merges) and counted the files that conflicted. I also read the open PRs' diffs against their bases.

hot spot	conflicts in master's merges	open stacks that edit it
packages/parity/src/fixtures.ts (group list)	37	all five: REPL/FORM, text, PNT1/VIS/BG2, OVFL, PNT2
packages/dragon/src/faults.ts (one-line NO_FAULTS)	15	text, OVFL
scripts/regen.ts (STEPS, MANUAL) and .gitattributes	7	text, PNT1/BG2, OVFL, PNT2
packages/dragon/src/css/properties.ts (six family spreads)	4	TDEC, VIS
paint registries (one-line PaintWrite, AnyLowering and PaintPlantName unions)	1	10 PRs: REPL, PNT1 ×6, VIS, BG2, PNT2
animation-kinds.ts	1	REPL, and every lane that adds a longhand
diagnostics/codes.ts, catalogue.ts and test/diagnostic-codes.json	0 so far	REPL and TXT1a, both appending at the end

The other hot spots this PR does not split:

• pixel-reference.test.ts (22 conflicts) is already fixed by the PIN-DERIVE: derived checks replace literal count pins that conflict on every landing #125 floors.
• seams.test.ts and paint-seams.test.ts (7 and 5 conflicts; 13 and 15 open PRs) still pin global lists such as paintPlants(), PAINT_EMITTERS kinds and SUPPORT_FILES. They should move to floors next.
• device-failures-*.json is device output.
• stylesheet.ts and values.ts are code, not lists.

Migration note for in-flight lanes (do this at your next catch-up)

At the catch-up merge, take master's side of every hot-spot file below and move your additions into your own file. The
empty per-feature files named here already exist on master, so two lanes no longer edit the same lines.

All lanes

• Diagnostic codes: do not append to diagnostics/codes.ts, catalogue.ts or test/diagnostic-codes.json (now frozen). Put your codes and their catalogue entries in packages/dragon/src/diagnostics/codes/<feature>.ts as diagnosticFeature([...codes], { CODE: error(...), ... }), and pin them in packages/dragon/test/diagnostic-codes/<feature>.json. A new feature adds its import and one line in DIAGNOSTIC_FEATURES, each in sorted order.
• Faults: do not edit faults.ts. Put the fault type (one documented field per fault) and its defaults (false) in packages/dragon/src/faults/<feature>.ts. A new feature adds its import and one line in FAULT_GROUPS, each in sorted order.
• Paint modules: delete your edits to PaintWrite, AnyLowering and their import type lines in lower/paint/registry.ts, and to PaintPlantName in emit/paint/registry.ts. Both are now derived. Type your lowering as PaintLowering<YourWrite> (you already do), and declare your plant names as the emitter's second type parameter: PaintEmitter<'kind-a' | 'kind-b', 'plant-1' | 'plant-2'>. A new module still adds one line to PAINT_MODULE_NAMES, LOWERINGS and EMITTERS.
• Property families: delete your spreads from the six tables in properties.ts. A new family adds its import and one line in FAMILIES, family('<id>', X_LONGHANDS, X_SHORTHANDS, X_INHERITED, X_ASPECTS, X_CONTAINER, X_TEXT_ROLE), placed after the family it follows. Longhands added to an existing family need no properties.ts change.
• Animation kinds: put each longhand's kind in packages/dragon/src/css/animation-kinds/<family>.ts. The paint seam families (radius, shadow, effects, outline, background-layers, scrollbar) already have empty files. A new family adds its file, its import and one ...X_ANIMATION line, each in sorted order.
• Fixture groups: delete your import and FIXTURE_GROUPS line. Add '<group-id>': YOUR_GROUP, to GROUPS and your import, each in sorted order. Groups added after the split run after the legacy groups (after states), in id order, so run pnpm regen after the catch-up and retarget any pin that counts on your group's position (for example a values.test slice(-n); the legacy slice is now LEGACY_RUN_ORDER.length - 2 .. LEGACY_RUN_ORDER.length).
• Regen steps: do not edit STEPS or MANUAL in scripts/regen.ts. Put your additions in scripts/regen-steps/<feature>.ts as { steps: [{ after: '<step>', step: {...} }], outputs: { '<existing step>': ['extra/glob/**'] }, manual: [{ command, outputs }] }. A new feature adds its import and one line in REGEN_FEATURES, each in sorted order. Add your .gitattributes line in sorted position (the file is sorted now).

Per lane

• REPL-a (REPL-a 2/3: img and iframe compiled as block-level replaced boxes (lands with 3/3) #69, REPL-a 3/3: images painted into the engine destination rect, iframes as platform web views that load src (lands with #69) #72) and FORM-a (FORM-a 1/3: the engine's form-control box kind (range, slider thumb, block button), laid out by layout() against Chrome's boxes #77–FORM-a 3/3: input[type=range] as Chrome's UA shadow tree, CSS-painted, with the slider pseudo-elements cascaded per part #79): move DRAGON_REMOTE_IMAGE and DRAGON_UNSUPPORTED_IMAGE into diagnostics/codes/repl-a.ts and test/diagnostic-codes/repl-a.json. Declare 'image-offset-1' on IMAGE_EMITTER's type. Add GROUPS lines controls and replaced. Put the object-fit and object-position kinds in their family's animation-kinds/<family>.ts.
• Text stack (INL1a INL1a 2/5 (B1): the inline input model (InlineBox, LineBreak, strut, verticalAlign) and its additive vector migration #88–INL1a 5/5 (C2): lowering inline boxes and <br>s, native runtime emit, 7 inline fixtures and lanes #91, TXT1a TXT1a-1a (v2): Ahem through HarfBuzz, and the zoomInput platform rule, restacked onto INL1a C2 #101–TXT1a-2 (v2): native real faces and the text-latin cases in FIXTURES, restacked onto INL1a C2 #104, INL1a-tags (v2): b, strong, em and i (T133), restacked onto the text stack #105, TXT-W TXT-W1 (v2): font-weight and font-style, restacked onto the text stack #106–TXT-W2 (v2): the font shorthand and font-synthesis, restacked onto the text stack #107, TDEC TDEC-a1 (v2): text-decoration in the compiler, restacked onto the text stack #108–TDEC-a2 (v2): decoration geometry and the decoration capture, restacked onto the text stack #109, INL2 INL2a 1/2: atomic inlines in the layout engine (inline-block, inline-flex) #112/INL2a 2/2: inline-block and inline-flex in the compiler, with Chrome fixtures #115, TXT2 TXT2-a 1/2: overflow-wrap and word-break: break-word in the layout engine (UAX #29 graphemes) #117): put brAsSpace and inlineWrapperPerElement in faults/inl1a.ts, and atomicCollapsesAsLineEnd in faults/inl2a.ts. Move DRAGON_SYNTHETIC_FONT_STYLE into diagnostics/codes/txt1a.ts and test/diagnostic-codes/txt1a.json; TXT-W1's wording edit goes to the same file. TDEC adds family('text-decoration', ...) after the text line, plus animation-kinds/text-decoration.ts and its spread line; the font-weight, font-style and font-synthesis kinds go in animation-kinds/text.ts. Add GROUPS lines atomic-inline, font-shorthand, inline-tags, text-calibration, text-decoration, text-latin and text-weight, then regen. In regen-steps/txt1a.ts, add outputs: { vectors: ['packages/layout/vectors/text-latin/dpr-1/**'], 'dpr-vectors': [the dpr-2, dpr-3 and dpr-2.625 globs] }. In regen-steps/tdec.ts, add { after: 'pixel-capture', step: decoration-capture }. In regen-steps/txt2.ts, add the grapheme manual entry.
• PNT1 (PNT1 1/8: radius and shadow paint engines (paint-radius.ts, paint-shadow.ts, paint-aa.ts), vectors and host plumbing #80–PNT1 8/8: Appendix E foreground phase, flex items atomic #87), VIS (T150a visibility, paint part: hidden and collapse on non-table boxes, natively (stacked on #87) #94) and BG2 (BG2-a1 gradient raster engine: paint-gradient.ts without the libm port, the measured libm table, layer origin and edge offsets (stacked on #94) #99, BG2-a2 gradient compiler: layer longhands, gradients, R3 slopes, native-only refusals (stacked on #99) #110, BG2-a3 native: gradient layers drawn by Dragon on iOS and Android (stacked on #110) #119): declare plants on the emitter types: radius 'radius-square', shadow 'shadow-offset-1', effects 'alpha-ignored', stacking 'order-swap' | 'foreground-under', outline 'outline-offset-1', gradient 'gradient-offset-1' | 'gradient-unpremultiplied-upload', visibility 'visibility-ignored' | 'visibility-subtree'. Add GROUPS lines color-scheme, gradients, opacity, outline, radius, shadow, stacking and visibility. VIS adds family('visibility', ...) after scrollbar, plus animation-kinds/visibility.ts and its spread line. PNT1 fills the existing animation-kinds/radius.ts, shadow.ts, effects.ts and outline.ts. In regen-steps/pnt1.ts, add { after: 'anim-capture', step: paint-inputs }. Your narrowing of the legacy dash MANUAL entry stays an edit in regen.ts. In regen-steps/bg2.ts, add { after: 'notices', step: libm } and the gradient manual entry.
• OVFL (OVFL A 1/2: scroll containers in the engine (overflow auto, scroll, clip; Blink scrollable overflow port) #96, OVFL A 2/2: scroll containers in the compiler, viewport propagation and Chrome scroll metrics #97): put propagationFromBody in faults/ovfl.ts. Add GROUPS line overflow. In regen-steps/ovfl.ts, add { after: 'dpr-capture', step: scroll-capture }.
• PNT2 (PNT2 3/3: transforms against Chrome (fixtures, transform twin and content quads, mapped samples, raster plants) #74): declare 'transform-origin-ignored' | 'translate-percent-of-parent' on TRANSFORM_EMITTER's type. Add GROUPS line transforms. In regen-steps/pnt2.ts, add { after: 'ua', step: quads }.
• GRID (GRID G1a (1/3): grid engine input, grid lowering and grid contexts #32): no hot-spot edits.

Expected leftovers, all one-line conflicts: two new fixture groups next to each other in sorted order, such as outline/overflow (PNT1/OVFL), radius/replaced (PNT1/REPL), controls/font-shorthand (FORM/TXT) and text-weight/transforms (TXT/PNT2); and neighbouring .gitattributes lines, such as expected-quads/expected-scroll (PNT2/OVFL).

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[thejackshelton]

Landing stopped at step typecheck (pnpm land)

pnpm typecheck SIGTERM (log /tmp/land-138-typecheck.log)

Fix the cause, then hand #138 back to the landing queue with the new clean head.