GROOVY-11770: StackOverflowError processing generics for kubernetes-c…

[paulk-asert]

…lient library (cycle guard instead of try/catch)

Caveat: the cycle guard uses object identity. If the recursion ever creates fresh ClassNode instances at each level for the same logical pair, identity won't catch it and we'd be back to SOE territory, except now without the catch as a backstop.

We could consider keeping the SOE catch around the recursive call as a final safety net (with a comment like "should be unreachable; cycle guard handles known cases").

[codecov-commenter]

Codecov Report

❌ Patch coverage is 88.46154% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.2365%. Comparing base (8dde1c8) to head (2588f48).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
.../codehaus/groovy/ast/tools/WideningCategories.java	88.4615%	0 Missing and 3 partials ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##               master      #2498        +/-   ##
==================================================
+ Coverage     67.2264%   67.2365%   +0.0101%     
- Complexity      31984      31988         +4     
==================================================
  Files            1468       1468                
  Lines          123923     123946        +23     
  Branches        22251      22257         +6     
==================================================
+ Hits            83309      83337        +28     
+ Misses          33433      33428         -5     
  Partials         7181       7181                

Files with missing lines	Coverage Δ
.../codehaus/groovy/ast/tools/WideningCategories.java	83.2714% <88.4615%> (+0.8714%)	⬆️

... and 2 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.

[Copilot]

Pull request overview

Addresses GROOVY-11770 by preventing StackOverflowError during generics LUB (lowest-upper-bound) computation (notably seen with kubernetes client types) via an explicit recursion/cycle guard rather than relying on catching SOE.

Changes:

• Add a new STC regression test that exercises an F-bounded generic LUB cycle through a wrapper type.
• Introduce a LowestUpperBoundContext to track in-flight (t1, t2) LUB computations and break recursion cycles during LUB parameterization.
• Refactor lowestUpperBound(ClassNode, ClassNode) to route through a context-aware private overload.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/test/groovy/groovy/transform/stc/GenericsSTCTest.groovy	Adds GROOVY-11770 regression test intended to ensure LUB computation does not overflow the stack.
src/main/java/org/codehaus/groovy/ast/tools/WideningCategories.java	Adds identity-based cycle guard context for recursive LUB parameterization; removes SOE catch.