fix: omit group anchor_alignment and subcircuit_id instead of writing null (#2845)

[DPS0340]

Closes #2845.

<group /> wrote null into two fields that circuit-json types as string-or-absent, so both elements failed validation:

                                    before                    after
pcb_group.anchor_alignment          null (rejected)           undefined → schema default "center"
schematic_group.subcircuit_id       null (rejected)           undefined

Why undefined rather than a value

pcb_group.anchor_alignment     → ninePointAnchor.default("center")
schematic_group.subcircuit_id  → z.string().optional()

For anchor_alignment, omitting is strictly better than substituting "center" in core: the schema already supplies that default, so leaving it out keeps a single source of truth and stays correct if the default ever changes. The explicit pcbAnchorAlignment prop still passes through unchanged — the test asserts a "top_left" group survives, so this can't be satisfied by blanket-clearing the field.

For subcircuit_id, the ! assertion was hiding that the field is string | null = null on the component. A group outside any subcircuit genuinely has none, and undefined is what the schema expects.

Three existing tests recorded the invalid values

That's why nothing caught this — the bug was baked into expectations:

• group-outline.test.tsx — "anchor_alignment": null
• group-subcircuit-id.test.tsx — "anchor_alignment": null
• group-schematic-box.test.tsx — "subcircuit_id": null

All three updated to undefined. No assertion was weakened; they're inline snapshots of emitted values.

Verification

The test bites. Reverting Group.ts:

Received: null
(fail) groups do not emit null anchor_alignment / subcircuit_id

It asserts neither field is null, that an explicitly requested alignment survives, and that neither field appears in safeParse issues — so it pins the schema contract rather than just the absence of null.

Suite: 1260 pass / 0 fail, tsc --noEmit 0 errors, biome format clean.

Note

Locating one of the three failures took a moment because five test files share the test name "group schematic box" — a single-file rerun of the wrong one passes and looks like flakiness. I isolated it by running each candidate file separately.

This is the third and final batch from validating core's output against circuit-json's exported schemas (#2841 display_offset_x/y, #2843 hole elements). With this merged, <group /> no longer contributes violations.

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Project	Deployment	Actions	Updated (UTC)
tscircuit-core-benchmarks	Ready	Preview, Comment	Jul 25, 2026 5:11pm

[DPS0340]

Housekeeping — rebased onto current main (d99c99f), still 1260 pass / 0 fail. No behaviour change.

Since I have several PRs open here now, a note on how they interact so none of this lands on you:

Five of the seven are fully independent — they touch different files and merge in any order:

PR	file
#2838	Inductor.ts
#2844	Hole.ts, PlatedHole.ts
#2846	Group/Group.ts (group insert sites)
#2840	Group/Group.ts (pcb_trace segment insert)
#2842	NormalComponent.ts, Group/Group.ts, Group_doInitialPcbComponentAnchorAlignment.ts

Two pairs conflict, and both are trivial:

1. fix: omit the voltage half of the fuse label when voltageRating is absent (#2833) #2834 ↔ fix: honour schShowRatings={false} on fuse (#2835) #2836 — both edit Fuse._getSchematicSymbolDisplayValue(). Whichever merges first, the other needs the two guards stacked:

   if (this._parsedProps.schShowRatings === false) return undefined   // #2836
   if (voltage === undefined || Number.isNaN(voltage)) return currentDisplay  // #2834
   return `${currentDisplay} / ${formatSiUnit(voltage)}V`

   They're orthogonal (one suppresses the whole label, the other drops just the voltage half), so the combined behaviour is well-defined. Both test files also touch fuse.test.tsx, appending separate tests.

2. fix: carry net highlightColor into pcb_trace.highlight_color (#2839) #2840 ↔ fix: write display_offset_x/y as display strings (#2841) #2842 — both add a field to nearby inserts in Group.ts; the resolution is to keep both lines.

Happy to do the merge myself: say the word and I'll combine any subset into a single PR, or rebase the losers as soon as the first one lands. I'd rather you not spend time on conflict resolution for my changes.

I verified the above rather than assuming it — checked all 21 branch pairs for conflicts and confirmed each rebases cleanly onto d99c99f.