fix: promotion dialog only fires for genuine pawn promotions

The "Promote pawn" dialog popped for any pawn "moved" toward the last
rank: the commit paths checked piece type + destination rank but never
the pawn's SOURCE rank. With the phantom layer now filling ranks 7-8
with tappable phantom pieces, tapping one (which falls through to the
real-move handler) while a real pawn was armed triggered the dialog for
a move no pawn could make — and for any phantom type, not just pawns.

Root cause: incomplete promotion detection, duplicated in Game.svelte
`onCommit` and the server's `isPromotionRequired`. Replaced with one
shared `isPromotionMove(piece, from, to)` — pawn, from the rank adjacent
to promotion, to the promotion rank, at most one file over — used by
both. 7 unit tests in packages/shared.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

This commit is contained in:

claude (blind_chess)

2026-05-18 21:45:42 -04:00

parent 5d995eb428

commit c01244c850

5 changed files with 77 additions and 13 deletions

									
										packages/shared/src/index.ts
									
		+1
		
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				@@ -3,3 +3,4 @@ export * from './moderator.js';

				export * from './protocol.js';

				export * from './geometric.js';

				export * from './phantoms.js';

				export * from './promotion.js';