fix: canonicalize double rendering#999
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Scala.js has different Double.tostring, fixing |
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Motivation: Double rendering was split across renderer implementations and depended on platform defaults. JVM emitted uppercase scientific notation, Scala.js/Wasm used different fixed/scientific thresholds, and large whole doubles could expose exact binary64 noise in some manifestation paths. Modification: Route renderers through RenderUtils.renderDouble. Canonicalize double strings by keeping common JSON-range values in fixed decimal form, normalizing smaller scientific notation, and rendering out-of-Long-range whole doubles from BigDecimal.valueOf instead of the exact binary constructor. Keep TOML in sync and update directional/golden tests. Document two design choices that otherwise read as arbitrary: - The [1e-6, 1e21) fixed-decimal window is ECMAScript's Number.prototype.toString convention, which JSON/Java/Scala.js all follow. - HALF_EVEN on BigDecimal.valueOf(d) is equivalent to any other tie-breaking rule in this branch, because doubles that reach it have |d| >= 2^53 where ULP >= 1 and no representable value is an exact .5 tie. Result: sjsonnet now renders representative doubles consistently across JVM, JS, Wasm, and Graal without claiming Go/C++ exact-digit compatibility. - 0.000001 -> 0.000001 - 0.0000001 -> 1e-07 - 1e100 -> 1 followed by 100 zeros (no binary64 noise) Tests: - scalafmt on changed files - ./mill __.checkFormat - ./mill sjsonnet.jvm[2.13.18].test (all pass) - ./mill sjsonnet.js[2.13.18].test (all pass) - ./mill sjsonnet.wasm[2.13.18].test (all pass) - sjsonnet/test/graalvm/run_test_suites.py References: None - double rendering canonicalization.
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Motivation
Double rendering was split across five renderer implementations
(
BaseByteRenderer,BaseCharRenderer,BaseRenderer,ByteRenderer,Renderer+TomlRenderer), depended on platform defaults (JVM emitsuppercase
1.0E-6, Scala.js/Wasm emit lowercase1e-7), and large wholedoubles exposed exact binary64 noise via
new BigDecimal(d).Modification
RenderUtils.renderDouble.ewith explicit signand 2-digit exponent padding.
BigDecimal.valueOf(d)instead ofnew BigDecimal(d)forout-of-Long whole doubles, eliminating binary64 noise.
TomlRendererwith the shared helper.Number.prototype.toStringconvention for the[1e-6, 1e21)fixed-decimal window.Result
Stable, canonical double rendering across JVM / JS / Wasm / Graal:
0.000001->0.0000010.0000001->1e-071e100->1+ 100 zerosAll tests pass on JVM/JS/Wasm/Native/Graal.
References
None — double rendering canonicalization.