fix(lint): require single to target on transition statement#62
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Adds `transitionTargetPass` enforcing SPEC §5.10: a `transition` statement must have exactly one `to <target>` clause. - Bare `transition` (no target) was silently accepted. - Multiple `to` clauses (`transition to @A, to @b`) were silently accepted. Both now produce ERROR diagnostics with stable codes `transition-missing-target` and `transition-multiple-targets` and spec-referenced messages. Fixtures cover the bare form, `with`-only, missing-`to` typo, and multi-target cases.
The four finding-*.agent fixtures were not referenced by any test — inline source strings in transition-target.test.ts already cover all cases, matching the pattern used by every other lint pass in the repo.
Match the existing convention — no other lint pass cites SPEC § in its user-facing message.
attachDiagnostic expects AstNodeLike; TransitionStatement does not widen automatically, so the guard is load-bearing for the type check even though the runtime invariant is already established by enterNode.
setu4993
approved these changes
Jun 15, 2026
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| const MISSING_TARGET_MESSAGE = | ||
| "'transition' requires a target. Use 'transition to <target>'."; | ||
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| const MULTIPLE_TARGETS_MESSAGE = | ||
| "'transition' accepts a single 'to' target. " + | ||
| "Multiple 'to' clauses are not allowed."; |
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These just get used here, so weird to have them defined as constants.
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java habbit :)
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Summary
Adds a new lint pass
transitionTargetPassenforcing SPEC §5.10: atransitionstatement must have exactly oneto <target>clause.Two silent acceptance bugs are fixed:
transitionwith no target — currently parsed and compiled with zero diagnostics.toclauses on a single transition (e.g.transition to @a, to @b) — silently accepted; only one target is meaningful.Both now produce ERROR diagnostics with stable codes
transition-missing-targetandtransition-multiple-targetsand spec-referenced messages. The missing-target diagnostic range is narrowed to thetransitionkeyword token so the squiggle points at the actual problem.Test plan
packages/language/src/lint/transition-target.test.ts(5 cases: valid form, bare, two-target, three-target, validto ... with k=v)pnpm --filter @agentscript/language test→ 192/192 passingpnpm --filter @agentscript/compiler test— no new regressions (pre-existing failures onmainare unrelated to this change)