📭 fix: Reject Empty Provider Streams

[lia-by-librechat]

Summary

A provider stream that yields zero chunks left finalChunk undefined, returned [undefined], and crashed during tool-call collection with an opaque TypeError.

Reject normal zero-chunk completion with The model provider returned an empty response. before constructing the result. Preserve intentional preemption and emitted chunks with empty content.

Add real-model regression coverage for local, custom onChunk, and registered-handler streaming across OpenAI, Anthropic, and Bedrock.

Fixes #594.

Verification

• Before the fix: all nine zero-chunk cases reproduced the original TypeError.
• After the fix: 446 tests passed across 22 focused invocation, preemption, protection, and tracing suites.
• Workspace npx tsc --noEmit, touched-file ESLint/import checks, and npm run build passed.
• Built CommonJS and ESM smoke tests passed.
• All 13 CI checks passed.
• Independent source review of 1c2f587fa64ae9b0927a9a3252bf80b0e88eeafe: no findings. No findings to fix or reject.

[lia-by-librechat]

Head: 1c2f587fa64ae9b0927a9a3252bf80b0e88eeafe

Rejects zero-chunk provider completion with a clear error. Preserves intentional restarts and emitted empty-content chunks. Regression coverage exercises all three stream paths across OpenAI, Anthropic, and Bedrock.

Verified: 446 tests across 22 focused suites; workspace typecheck; touched-file lint/import checks; package build; built CommonJS/ESM smoke tests. All 13 CI checks passed.

Independent source review: complete on this exact head, no findings at any severity. Reviewer did not run tests/builds; local verification above was run separately. No rejected findings.

Not run locally: full test suite or live-provider integration tests.

[danny-avila]

@codex review the latest head, final review

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-05T13:45:30.234905Z	1c2f587	Manual request

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[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Chef's kiss.

Reviewed commit: 1c2f587fa6

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