Fix Schema Union candidate pruning

[gcanti]

Summary by CodeRabbit

• Bug Fixes

  • Improved union schema candidate selection for recovering middleware and suspended members.
  • Fixed runtime dispatch for unions using decoding or encoding recovery.
  • Preserved lazy evaluation for suspended union members, avoiding unnecessary evaluation after a successful match.

• Tests

  • Added coverage for recovering members, sentinel dispatch, lazy suspensions, and recursive suspended schemas.

[changeset-bot]

🦋 Changeset detected

Latest commit: 4644bc0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 29 packages

Name	Type
effect	Patch
@effect/opentelemetry	Patch
@effect/platform-browser	Patch
@effect/platform-bun	Patch
@effect/platform-deno	Patch
@effect/platform-node-shared	Patch
@effect/platform-node	Patch
@effect/vitest	Patch
@effect/ai-anthropic	Patch
@effect/ai-openai-compat	Patch
@effect/ai-openai	Patch
@effect/ai-openrouter	Patch
@effect/atom-react	Patch
@effect/atom-solid	Patch
@effect/atom-vue	Patch
@effect/sql-clickhouse	Patch
@effect/sql-d1	Patch
@effect/sql-libsql	Patch
@effect/sql-mssql	Patch
@effect/sql-mysql2	Patch
@effect/sql-pg	Patch
@effect/sql-pglite	Patch
@effect/sql-sqlite-bun	Patch
@effect/sql-sqlite-do	Patch
@effect/sql-sqlite-node	Patch
@effect/sql-sqlite-react-native	Patch
@effect/sql-sqlite-wasm	Patch
@effect/docgen	Patch
@effect/openapi-generator	Patch

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: d490cf9b-7713-4db5-aa92-02b9ccb5bd38

📥 Commits

Reviewing files that changed from the base of the PR and between d48506d and 4644bc0.

📒 Files selected for processing (3)

• .changeset/fix-schema-union-pruning.md
• packages/effect/src/SchemaAST.ts
• packages/effect/test/schema/Schema.test.ts

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📝 Walkthrough

Walkthrough

Changes

Schema union candidate selection

Layer / File(s)	Summary
Candidate derivation and dispatch integration packages/effect/src/SchemaAST.ts	Adds memoized candidate resolution for encoding, middleware, and suspended AST nodes, then uses it for union indexing and literal filtering.
Recovering and suspended member regression coverage packages/effect/test/schema/Schema.test.ts, .changeset/fix-schema-union-pruning.md	Tests recovering branches, sentinel dispatch, suspension laziness, and recursive suspended unions; adds a patch changeset.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• Effect-TS/effect#6635: Adjusts related union candidate fallback logic in SchemaAST.ts.
• Effect-TS/effect#6646: Uses SchemaAST union candidates for compiled schema behavior.

Suggested reviewers: patroza, tim-smart

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[github-actions]

Bundle Size Analysis

File Name	Current Size	Previous Size	Difference
basic.ts	6.63 KB	6.63 KB	0.00 KB (0.00%)
batching.ts	9.42 KB	9.42 KB	0.00 KB (0.00%)
brand.ts	6.29 KB	6.29 KB	0.00 KB (0.00%)
cache.ts	10.12 KB	10.12 KB	0.00 KB (0.00%)
config.ts	19.89 KB	19.77 KB	+0.12 KB (+0.59%)
differ.ts	19.06 KB	18.96 KB	+0.10 KB (+0.52%)
http-client.ts	20.94 KB	20.94 KB	0.00 KB (0.00%)
logger.ts	10.28 KB	10.28 KB	0.00 KB (0.00%)
metric.ts	8.55 KB	8.55 KB	0.00 KB (0.00%)
optic.ts	7.45 KB	7.45 KB	0.00 KB (0.00%)
pubsub.ts	14.26 KB	14.26 KB	0.00 KB (0.00%)
queue.ts	11.09 KB	11.09 KB	0.00 KB (0.00%)
schedule.ts	10.27 KB	10.27 KB	0.00 KB (0.00%)
schema-class.ts	18.84 KB	18.72 KB	+0.12 KB (+0.64%)
schema-fromJsonSchemaDocument.ts	28.75 KB	28.69 KB	+0.06 KB (+0.21%)
schema-representation-roundtrip.ts	25.05 KB	24.98 KB	+0.07 KB (+0.30%)
schema-string-transformation.ts	12.96 KB	12.96 KB	0.00 KB (0.00%)
schema-string.ts	10.65 KB	10.65 KB	0.00 KB (0.00%)
schema-template-literal.ts	14.85 KB	14.85 KB	0.00 KB (0.00%)
schema-toArbitraryLazy.ts	21.62 KB	21.52 KB	+0.10 KB (+0.45%)
schema-toCodeDocument.ts	24.07 KB	24.00 KB	+0.07 KB (+0.28%)
schema-toCodecJson.ts	18.97 KB	18.87 KB	+0.10 KB (+0.52%)
schema-toEquivalence.ts	18.69 KB	18.59 KB	+0.11 KB (+0.57%)
schema-toFormatter.ts	18.56 KB	18.45 KB	+0.10 KB (+0.57%)
schema-toJsonSchemaDocument.ts	22.19 KB	22.08 KB	+0.11 KB (+0.48%)
schema-toRepresentation.ts	19.23 KB	19.13 KB	+0.10 KB (+0.53%)
schema.ts	18.10 KB	18.00 KB	+0.10 KB (+0.58%)
stm.ts	12.05 KB	12.05 KB	0.00 KB (0.00%)
stream.ts	9.37 KB	9.37 KB	0.00 KB (0.00%)