[Bugfix] Fix Kimi-K2 tool parser concatenated tool calls parsing

[yiyeguhu]

[Bugfix] Fix Kimi-K2 tool parser concatenated tool calls parsing

Purpose

• Resolves GitHub issue #24478
• Fix regex pattern to handle concatenated tool calls without spacing
• Use negative lookahead to prevent over-matching across tool call boundaries
• Add comprehensive test cases for edge cases including angle brackets in JSON
• Consolidate test cases into parametrized test for better maintainability

Test Plan

pytest tests/tool_use/test_kimi_k2_tool_parser.py

Test Result

All 11 tests pass, including 4 new test cases that validate the regex fix:

• concatenated_tool_calls_bug_fix: Exact GitHub issue reproduction
• three_concatenated_tool_calls: Scalability test
• mixed_spacing_tool_calls: Robustness test
• angle_brackets_in_json: Edge case with HTML in JSON

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[MoyanZitto]

LGTM

[wizche]

Why is this not being merged?

[mehmetbaykar]

any update on this?

[bbartels]

@yiyeguhu Could you fix the pre-commit issues, all other tests seem to have passed! See here: https://github.com/vllm-project/vllm/actions/runs/19263038741/job/55072168601?pr=24847

[chaunceyjiang]

@bbartels Could you help submit a new PR based on this one?

[bbartels]

@bbartels Could you help submit a new PR based on this one?

@chaunceyjiang Have a look at https://github.com/vllm-project/vllm/pull/28831

[mergify[bot]]

Hi @yiyeguhu, the pre-commit checks have failed. Please run:

uv pip install pre-commit
pre-commit install
pre-commit run --all-files

Then, commit the changes and push to your branch.

For future commits, pre-commit will run automatically on changed files before each commit.