fix: include ANTLR diagnostic in loads() ValidationError

[tonycoder-hub]

Summary of changes

openqasm3.parse often raises QASM3ParsingError with an empty message while printing the ANTLR diagnostic to stderr. pyqasm.loads() then produced ValidationError: Failed to parse OpenQASM string: with no reason for callers.

Capture stderr during parse and prefer that text when the exception message is empty, so the ValidationError includes the diagnostic (e.g. line 3:10 no viable alternative…).

Fixes #436

[argus-eye]

Argus review

Auto-review is off for this repo. Tick the box below to run a review on this PR.

• Trigger Argus review

Estimated cost

• Files changed: 2
• Diff lines (±): 24
• Historical avg: ~350.7k tokens · ~$1.38 · across last 13 review(s)

Tip: you can also comment @argus-eye review at any time.

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

• Configuration used: Repository: qBraid/pyqasm/.coderabbit.yaml
• Review profile: CHILL
• Plan: Advanced
• Run ID: 369ea70e-bd6b-40dc-8bc1-632e9be016e3

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!