fix: Retry-After-Ms header silently ignored due to str > int TypeError

[devteamaegis]

Bug

_parse_retry_after in src/cohere/core/http_client.py retrieves the Retry-After-Ms header and then compares the raw header string against an integer:

retry_after_ms = response_headers.get("retry-after-ms")  # always a str
if retry_after_ms is not None:
    try:
        return int(retry_after_ms) / 1000 if retry_after_ms > 0 else 0  # ← bug
    except Exception:
        pass

In Python 3, "1000" > 0 raises TypeError: '>' not supported between instances of 'str' and 'int'.
That exception is caught and silently discarded, so the Retry-After-Ms header is always ignored — every response that carries one falls through to Retry-After or exponential back-off instead.

Fix

Convert the header value to int before the comparison:

ms = int(retry_after_ms)
return ms / 1000 if ms > 0 else 0

Reproduction

from cohere.core.http_client import _parse_retry_after
import httpx

headers = httpx.Headers({"retry-after-ms": "2000"})
print(_parse_retry_after(headers))  # None (bug) — should be 2.0

Tests

Added tests/test_http_client.py with 10 unit tests covering positive values, zero, negative values, fractional milliseconds, invalid header content, header priority (Retry-After-Ms vs Retry-After), and the no-header case.

---

Note

Low Risk
Low risk: narrow bugfix in retry-delay parsing plus unit tests; only affects how backoff delay is computed when retry-after-ms is present.

Overview
Fixes _parse_retry_after to correctly handle retry-after-ms by converting the header string to an int before comparing/clamping, preventing a TypeError that previously caused the header to be silently ignored.

Adds a new tests/test_http_client.py suite covering retry-after-ms and retry-after parsing (valid/invalid values, priority, and no-header cases) to prevent regressions.

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