Broaden BigInt arbitraries independently of size and shrink large roots - #8282
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Unbounded BigInts previously used only [-size^2, size^2], with the same small width applied to one-sided constraints. Default samples therefore missed unsafe integer conversions, large integer arithmetic and overflow when converting to a floating-point number. Mix small, ordinary and large ranges up to 2048 bits independently of collection size. This exercises near-zero values and both signs without allowing a single enormous uniform interval to crowd out ordinary integers. Center and clip each range against one-sided bounds, and add a boundary range when an explicit limit on the far side of zero lies outside the default magnitudes. Both-bound generation keeps its existing sampling behavior and supports arbitrary-width explicit intervals. Before halving a large initial shrink gap, try smaller power-of-two offsets while preserving the preceding passing-candidate context. This lets the new large roots shrink to ordinary failure boundaries under the default 100-attempt budget instead of stopping hundreds of digits away. Candidates remain between the valid target and original value. Add deterministic small-size coverage, signed one-sided limits (including limits beyond the default magnitudes), exact inclusive/exclusive edges, valid shrink candidates, default-budget failure shrinking at zero and large nonzero targets, and replay. This commit is independent of the preceding BigDecimal fix and has been checked without that change. Validation (repository Nix development shell): - pnpm test --run packages/effect/test/unstable/arbitrary/BigInt.test.ts packages/effect/test/unstable/arbitrary/BigDecimal.test.ts packages/effect/test/unstable/arbitrary/Arbitrary.test.ts (210 tests) - pnpm check - pnpm lint-fix - pnpm lint - With original Schema.ts restored temporarily: BigInt.test.ts and Arbitrary.test.ts (183 tests), plus pnpm check
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🦋 Changeset detectedLatest commit: aef6de2 The changes in this PR will be included in the next version bump. This PR includes changesets to release 30 packages
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Closing in favor of #8296 |
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Problem
Unbounded BigInt arbitraries currently use roughly [-size², size²]. At the default size 10, only 201 integers are possible. One-sided constraints inherit a similarly narrow range, so ordinary samples miss unsafe integer conversions and very large integer arithmetic.
Simply widening one uniform interval would mostly generate huge values. Those values also expose a shrinking limitation: repeated halving exhausts the default 100-attempt budget before reaching useful small counterexamples.
Change
Mix small, ordinary and large ranges up to 2048 bits independently of collection size. Respect one-sided bounds and explicitly exercise their boundaries even when they lie outside the default magnitudes. Generation with both bounds supplied retains its existing behavior.
Before halving a large initial shrink gap, try smaller power-of-two offsets while retaining the previous passing candidate. This lets common failures shrink to useful boundaries within the default budget, including with large nonzero bounds.
This PR contains only the BigInt change and does not depend on the separate BigDecimal fix.
Validation
BigInt.test.tsandArbitrary.test.ts, with the original BigDecimal implementation, pluspnpm check.pnpm lint-fixandpnpm lintpassed in the repository's Nix development shell.The independent validation used Effect 4.0.0-rc.115 (
4a05d4914) as the base.