fix(worker): resolve 'Body has already been used' error on retry

[colegottdank]

Summary

• Fixes "Body has already been used" 500 errors that occurred when server-side retries were triggered (for 429 or 5xx responses from providers)
• Converts ReadableStream body to string before the retry loop so it can be safely reused

Problem

When callProviderWithRetry() retried requests after receiving 429 or 5xx responses from providers, the retry would fail with "Body has already been used" errors. This happened because:

1. The body in callProps could be a ReadableStream (when RequestBodyBuffer_Remote is used for large requests)
2. ReadableStream bodies can only be consumed once by fetch()
3. The first retry attempt consumed the stream, making it unusable for subsequent attempts

Solution

Convert any ReadableStream body to a string at the start of callProviderWithRetry() before entering the retry loop. Strings can be safely reused across multiple fetch() calls.

Test plan

• TypeScript check passes
• All 1421 worker tests pass

🤖 Generated with Claude Code

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[claude]

Claude finished @colegottdank's task —— View job

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Code Review Complete

Score: 8/10 - Good to merge, minor suggestions for improvement

This PR successfully fixes the "Body has already been used" error in the worker's retry logic. The core fix is solid and the approach is correct.

Core Fix Analysis (ProviderClient.ts)

✅ Problem identification: Correctly identified that ReadableStream bodies can only be consumed once by fetch()

✅ Solution approach: Converting ReadableStream to string before retry loop is the right approach

✅ Implementation: Clean implementation with proper error handling

Minor suggestions for the core fix:

1. Memory efficiency consideration (lines 194-204): For very large request bodies, converting the entire ReadableStream to a string could consume significant memory. Consider adding a size check or streaming approach for extremely large payloads.

2. Error handling: Consider wrapping the ReadableStream reading logic in a try-catch to handle potential stream read errors gracefully.

3. Type safety: The retryableBody variable could benefit from more explicit typing to ensure type safety.

Google Provider Changes Analysis

The Google provider changes appear to be related to adding support for reasoning/thinking features:

✅ Type additions: Added "minimal" and "medium" to thinkingLevel union types - proper type system updates

✅ Test coverage: Comprehensive test coverage for the reasoning functionality in google-reasoning.test.ts

✅ Documentation: Good inline comments explaining the reasoning configuration logic

Observations on Google changes:

• The changes are well-structured and follow existing patterns
• Test coverage is thorough with edge cases covered
• The mapping logic between OpenAI and Google formats looks correct

Potential Issues Found

Minor Performance Issue: In ProviderClient.ts line 203, the string concatenation approach could be optimized:

// Current approach
retryableBody = chunks.map((chunk) => decoder.decode(chunk)).join("");

// More efficient approach would be:
const totalLength = chunks.reduce((sum, chunk) => sum + chunk.length, 0);
const combined = new Uint8Array(totalLength);
let offset = 0;
for (const chunk of chunks) {
  combined.set(chunk, offset);
  offset += chunk.length;
}
retryableBody = decoder.decode(combined);

Type Safety Enhancement: Consider adding runtime validation for the body conversion to ensure the conversion doesn't fail silently.

Security & Quality Assessment

✅ No security issues identified
✅ No breaking changes
✅ Backward compatible
✅ Proper error boundaries maintained
✅ Good test coverage for new functionality

Suggestions Summary:

Critical fixes needed: None

Recommended improvements:

• Add error handling around ReadableStream reading
• Consider memory optimization for very large payloads
• Optimize string concatenation for better performance

Optional enhancements:

• Add runtime validation for body conversion
• Consider adding metrics/logging for retry scenarios with body conversion

The fix addresses the core issue effectively and the Google provider enhancements are well-implemented. The code quality is good and follows project conventions.

[greptile-apps]

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