return BigInteger for json integers beyond long range

[netliomax25-code]

1. JsonSlurper's default CHAR_BUFFER parser, the INDEX_OVERLAY and LAX overlay parsers, and the CHARACTER_SOURCE parser each pick a JSON integer's Java type with only an int-or-long check, so a value past Long.MAX_VALUE is never promoted to BigInteger.
2. CHAR_BUFFER (CharScanner.parseJsonNumber) and the overlay parsers (NumberValue.doToValue) fall through to parseLongFromTo, which wraps silently, so parsing 9999999999999999999 yields -8446744073709551617. CHARACTER_SOURCE (JsonParserUsingCharacterSource.decodeNumber) has no branch past isLong and returns null instead.
3. The lexer-based path (JsonToken.getValue) already returns Integer, Long, or BigInteger, so the parser types disagree on the same input.

Added the missing BigInteger branch at the three decode sites so every parser type matches the JsonToken contract. The new regression test runs across all four parser types and fails before the change.

[testlens-app]

✅ All tests passed ✅

⚠️ TestLens detected flakiness ⚠️

Test Summary

Build and test / lts (17, windows-latest, 1) > :test

Test	Runs
GenericsSTCTest > testReturnTypeInferenceWithMethodGenerics18()	🚫 ❌ ✅
GenericsSTCTest > testReturnTypeInferenceWithMethodGenerics18a()	🚫 ❌ ✅
GenericsStaticCompileTest > testReturnTypeInferenceWithMethodGenerics18()	🚫 ❌ ✅
GenericsStaticCompileTest > testReturnTypeInferenceWithMethodGenerics18a()	🚫 ❌ ✅

🏷️ Commit: 71ffc3b
▶️ Tests: 20273 executed
⚪️ Checks: 22/22 completed

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[Copilot]

Pull request overview

This PR aligns JsonSlurper’s integer type-selection behavior across its parser implementations so that JSON integers exceeding the long range are returned as BigInteger (instead of overflowing/wrapping or returning null), matching the existing JsonToken contract.

Changes:

• Extend integer decoding in the CHAR_BUFFER parser (CharScanner.parseJsonNumber) to promote beyond-long integers to BigInteger.
• Extend integer decoding in overlay parsers (NumberValue.doToValue) to promote beyond-long integers to BigInteger.
• Extend integer decoding in the CHARACTER_SOURCE parser (JsonParserUsingCharacterSource.decodeNumber) to return BigInteger for beyond-long integers, and add a regression test.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
subprojects/groovy-json/src/test/groovy/groovy/json/JsonSlurperTest.groovy	Adds a regression test for parsing an integer beyond Long.MAX_VALUE (note: as written, it only exercises the default parser type).
subprojects/groovy-json/src/main/java/org/apache/groovy/json/internal/NumberValue.java	Updates overlay-backed integer conversion to select BigInteger when the value doesn’t fit in int or long.
subprojects/groovy-json/src/main/java/org/apache/groovy/json/internal/JsonParserUsingCharacterSource.java	Updates character-source number decoding to construct a BigInteger when the value doesn’t fit in int or long.
subprojects/groovy-json/src/main/java/org/apache/groovy/json/internal/CharScanner.java	Updates CHAR_BUFFER number parsing to construct a BigInteger for integer tokens that exceed long range.

[paulk-asert]

Thanks again for another contribution. Did you want to create a Jira and address the Copilot comment?