[Fix] Resolve MiniMax-M3 top-level oneOf parameter schemas

[adolphinvx]

Motivation

Fixes #32286.

The MiniMax-M3 tool-call parser only looked for parameter schemas in direct
properties. When a tool used a top-level oneOf, the parser could not find
the selected property's schema, so numbers were emitted as strings and arrays
leaked raw MiniMax parser tags.

Modifications

• Resolve child parameter schemas recursively from top-level oneOf branches.
• Add a streaming CPU regression test covering number, string-array, and
  number-array branches from the reported failure.

Accuracy Tests

Not applicable. This changes deterministic tool-call argument parsing and does
not modify model inference or generated token output. The parser output is
covered by the regression unit test below.

Speed Tests and Profiling

Not applicable. The change adds a bounded schema lookup when a direct property
is not found and does not affect model execution.

Validation

• MiniMax-M3 detector unit tests: 24 passed.
• python3 -m py_compile on the changed source and test.
• Black 26.1.0, Ruff 0.15.1, and isort 7.0.0 checks.
• git diff --check.

Checklist

• Format your code according to the Format code with pre-commit.
• Add unit tests according to the Run and add unit tests.
• Update documentation according to Write documentations. (N/A: no API or user-facing behavior documentation changed.)
• Provide accuracy and speed benchmark results according to Test the accuracy and Benchmark the speed. (N/A: parser-only bug fix.)
• Follow the SGLang code style guidance.

Review and Merge Process

1. Ping Merge Oncalls to start the process. See the PR Merge Process.
2. Get approvals from CODEOWNERS and other reviewers.
3. Trigger CI tests with comments or contact authorized users to do so.
   • Common commands include /tag-and-rerun-ci, /tag-run-ci-label, /rerun-failed-ci.
4. After green CI and required approvals, ask Merge Oncalls or people with Write permission to merge the PR.

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CI States

Latest PR Test (Base): ❌ Run #30080151515
Latest PR Test (Extra): ❌ Run #30080151468

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

[adolphinvx]

@JustinTong0323 This PR is ready for review. The current red checks are from pr-gate blocking CI while the PR was still a draft; no test jobs ran. Could you please add the run-ci label and trigger CI when convenient? This is a focused MiniMax-M3 parser fix, and the 24 detector unit tests pass locally. Thank you!

[adolphinvx]

Superseded by #36626, which generalizes this fix to root-level anyOf/oneOf/allOf and was merged into main on Aug 28, 2026. Closing this PR.