fix(perf): skip spans with non-numeric encoded_body_size in LargeHTTPPayloadDetector

[billyvg]

Summary

Fixes SENTRY-5R9R — ValueError: invalid literal for int() with base 10: '[NaN]' in LargeHTTPPayloadDetector.

Root cause: In large_http_payload_detector.py:59, http.response_content_length span data can arrive as the string '[NaN]' (from scrubbed or filtered browser payloads). The bare int(encoded_body_size) call raises ValueError, which propagates through detect_performance_problems → _run_legacy_detectors → run_detector_on_data and gets caught by the logging.exception("Failed to detect performance problems") path — generating a Sentry error on every affected span.

Evidence from Sentry issue:

• 1,349 occurrences over 5 days (first seen 2026-07-07)
• encoded_body_size = "'[NaN]'" visible in local variables
• File: sentry/issue_detection/detectors/large_http_payload_detector.py, line 59

Fix: Wrap the int() conversion in a try/except ValueError and return early, skipping spans with unparseable body sizes.

# Before
if isinstance(encoded_body_size, str):
    encoded_body_size = int(encoded_body_size)

# After
if isinstance(encoded_body_size, str):
    try:
        encoded_body_size = int(encoded_body_size)
    except ValueError:
        return

A test test_skips_span_with_nan_encoded_body_size is added to confirm the behavior.

Claude session: https://claude.ai/code/session_015pwRdeFeVj3ZSak5yEbtaY

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Generated by Claude Code

[billyvg]

added encoded_body_size as safe field instead