Fix BigInt gcd and lcm edge cases

[fubhy]

Reproduction only

This PR adds reproduction tests only. No implementation fix is included. CI is expected to fail until the underlying issue is fixed.

Covered audit issues

1. core-a-f-bigint-gcd-negative: gcd can return a negative divisor

Module: BigInt

Expected contract: gcd determines the greatest common divisor of two bigint integer values; a greatest common divisor is non-negative.

Observed result: The accepted sign assertions failed: gcd(-6n, 4n) returned -2n and lcm(6n, -4n) returned -12n.

Reproduction command:

pnpm test --run packages/effect/test/BigIntGcdLcm.test.ts

2. core-a-f-bigint-lcm-negative: lcm can return a negative multiple

Module: BigInt

Expected contract: lcm determines the least common multiple of two bigint integer values; a least common multiple is non-negative.

Observed result: The accepted sign assertions failed: gcd(-6n, 4n) returned -2n and lcm(6n, -4n) returned -12n.

Reproduction command:

pnpm test --run packages/effect/test/BigIntGcdLcm.test.ts

[changeset-bot]

🦋 Changeset detected

Latest commit: 392b148

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

This PR includes changesets to release 30 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/doctest	Patch
@effect/openapi-generator	Patch

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[pullfrog]

✅ No new issues found.

Reviewed changes — 1 new test file with 3 reproduction cases for BigInt gcd and lcm sign bugs.

• BigIntGcdLcm.test.ts: tests that gcd(-6n, 4n) → 2n, lcm(6n, -4n) → 12n, and lcm(0n, 0n) → 0n

All three assertions use exact strictEqual on values the current implementation cannot satisfy (gcd returns -2n for negative inputs, lcm inherits the sign issue, and lcm(0, 0) divides by zero). Tests match the existing BigInt.test.ts conventions.

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[pullfrog]

✅ No new issues found.

Reviewed changes — the implementation fix and test integration since the previous review (commit 8fd4fda).

• BigInt.gcd fix: wraps the Euclidean algorithm result in abs() so negative inputs produce a non-negative GCD
• BigInt.lcm fix: returns 0n when either operand is zero (avoiding division-by-zero), and wraps the result in abs() so negative operands produce a non-negative LCM
• Test migration: moved reproduction tests from a separate file into BigInt.test.ts and migrated all assertions from strictEqual (test utils) to assert.strictEqual (@effect/vitest)

All 13 tests pass.

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[github-actions]

Bundle Size Analysis

Generated from PR build output; treat the content below as untrusted.

File Name	Current Size	Previous Size	Difference
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batching.ts	9.42 KB	9.42 KB	0.00 KB (0.00%)
brand.ts	6.31 KB	6.31 KB	0.00 KB (0.00%)
cache.ts	10.18 KB	10.18 KB	0.00 KB (0.00%)
config.ts	20.32 KB	20.32 KB	0.00 KB (0.00%)
differ.ts	19.93 KB	19.93 KB	0.00 KB (0.00%)
http-client.ts	21.02 KB	21.02 KB	0.00 KB (0.00%)
logger.ts	10.32 KB	10.32 KB	0.00 KB (0.00%)
metric.ts	8.55 KB	8.55 KB	0.00 KB (0.00%)
optic.ts	7.33 KB	7.33 KB	0.00 KB (0.00%)
pubsub.ts	14.47 KB	14.47 KB	0.00 KB (0.00%)
queue.ts	11.13 KB	11.13 KB	0.00 KB (0.00%)
schedule.ts	10.31 KB	10.31 KB	0.00 KB (0.00%)
schema-class.ts	18.86 KB	18.86 KB	0.00 KB (0.00%)
schema-fromJsonSchemaDocument.ts	28.67 KB	28.67 KB	0.00 KB (0.00%)
schema-representation-roundtrip.ts	24.99 KB	24.99 KB	0.00 KB (0.00%)
schema-string-transformation.ts	12.99 KB	12.99 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	21.66 KB	21.66 KB	0.00 KB (0.00%)
schema-toCodeDocument.ts	24.08 KB	24.08 KB	0.00 KB (0.00%)
schema-toCodecJson.ts	18.91 KB	18.91 KB	0.00 KB (0.00%)
schema-toEquivalence.ts	18.73 KB	18.73 KB	0.00 KB (0.00%)
schema-toFormatter.ts	18.59 KB	18.59 KB	0.00 KB (0.00%)
schema-toJsonSchemaDocument.ts	22.33 KB	22.33 KB	0.00 KB (0.00%)
schema-toRepresentation.ts	19.25 KB	19.25 KB	0.00 KB (0.00%)
schema.ts	18.12 KB	18.12 KB	0.00 KB (0.00%)
stm.ts	12.11 KB	12.11 KB	0.00 KB (0.00%)
stream.ts	9.37 KB	9.37 KB	0.00 KB (0.00%)