GROOVY-12139: vararg-of-arrays argument wrapping fails under classic …

[paulk-asert]

…compilation

GROOVY-11182's reproducer (a single byte[] passed to a byte[]... parameter) still failed with IllegalArgumentException when dispatched through MetaMethod#doMethodInvoke — the classic call-site path, and any other route through the reflective MOP invocation. The original fix only added a test; the invokedynamic chain's own varargs adaptation happened to handle the case, masking the gap under the default compilation mode.

Root cause: ParameterTypes#fitToVargs treated any trailing array argument as the pre-packed varargs array. Being an array is not sufficient — a byte[] passed to byte[]... is a single element of the byte[][] varargs array. The argument now passes through only when it is assignable to the varargs parameter type or is an array of the same dimension (whose elements the downstream argument coercion converts, e.g. Integer[] for int...); otherwise it is wrapped as an element.

Adds a classic-compilation (indy=false) variant of the GROOVY-11182 test. Also reproducible on GROOVY_5_0_X, so a candidate for backport.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 68.6889%. Comparing base (c6fa475) to head (2d46893).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
...org/codehaus/groovy/reflection/ParameterTypes.java	80.0000%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##               master      #2675        +/-   ##
==================================================
+ Coverage     68.5934%   68.6889%   +0.0955%     
- Complexity      33951      34106       +155     
==================================================
  Files            1535       1536         +1     
  Lines          128543     128903       +360     
  Branches        23335      23363        +28     
==================================================
+ Hits            88172      88542       +370     
+ Misses          32555      32530        -25     
- Partials         7816       7831        +15     

Files with missing lines	Coverage Δ
...org/codehaus/groovy/reflection/ParameterTypes.java	70.8108% <80.0000%> (+0.4811%)	⬆️

... and 10 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[testlens-app]

✅ All tests passed ✅

🏷️ Commit: 2d46893
▶️ Tests: 103206 executed
⚪️ Checks: 31/31 completed

---

Learn more about TestLens at testlens.app.

[Copilot]

Pull request overview

Fixes classic (non-invokedynamic) reflective MOP varargs adaptation for “vararg-of-arrays” cases, where a trailing array argument was incorrectly treated as the already-packed varargs array (e.g., byte[] passed to byte[]... should be wrapped into byte[][]).

Changes:

• Refines ParameterTypes#fitToVargs so the last argument only passes through as the varargs array when it’s assignable to the varargs parameter type, or when it’s an array of the same dimension (allowing downstream coercion like Integer[] → int[]).
• Adds a classic-compilation (indy=false) regression test variant for GROOVY-11182 to cover the MetaMethod#doMethodInvoke path.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/test/groovy/bugs/Groovy11182.groovy	Adds a classic-compilation regression test using GroovyShell with indy=false to exercise the reflective/MOP call-site path.
src/main/java/org/codehaus/groovy/reflection/ParameterTypes.java	Updates varargs argument “fit” logic to avoid misclassifying trailing arrays as the pre-packed varargs array in vararg-of-arrays scenarios.