fix: use context manager for file operations in cardiology_detect.py (Fixes #1171)

[rtmalikian]

Fixes #1171

Problem

pyhealth/tasks/cardiology_detect.py uses bare open().readlines() calls in 5 places. These rely on CPython's reference counting for file handle cleanup, which is not guaranteed behavior across all Python implementations.

Root Cause

The original code uses the pattern:

label_content = open(os.path.join(root, label), "r").readlines()

This leaves the file handle cleanup to garbage collection rather than explicit resource management.

Solution

Replaced all 5 occurrences with with open() as f: context managers:

with open(os.path.join(root, label), "r") as f:
    label_content = f.readlines()

Verification

• grep -c "= open(" pyhealth/tasks/cardiology_detect.py → 0 (all bare open calls removed)
• ast.parse(): syntax check passes
• git diff: 10 insertions, 5 deletions across 5 sites

Changelog

Date	Change	Author
2026-07-01	Replace 5 bare open() calls with context managers	rtmalikian

Files Changed

• pyhealth/tasks/cardiology_detect.py — Wrapped 5 open().readlines() calls in with statements

Verification

• 0 bare open() calls remaining in the file
• Syntax check: ast.parse() passes

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About the Author: Raphael Malikian — Clinical AI Solutions Architect. I specialise in building and fixing AI/ML systems for healthcare, including vector databases, RAG pipelines, and clinical NLP. If you need help with your project or think I can add value to your organisation, feel free to reach out — I'd love to connect.

📧 rtmalikian@gmail.com
🔗 GitHub: https://github.com/rtmalikian
🔗 LinkedIn: http://www.linkedin.com/in/raphael-t-malikian-mbbs-bsc-hons-71075436a

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Disclosure: This code was developed with assistance from DeepSeek-V4 (DeepSeek) via Hermes Agent (Nous Research). All changes were reviewed, tested against the actual codebase, and verified for correctness.