fix(build_environment): re-raise exception for the JSON parse failure

[LalatenduMohanty]

Previously, if json.loads() failed, the except block logged the error but did not re-raise, causing an UnboundLocalError on the next line where mapping was undefined. Now the original exception is re-raised.

Closes: #1023

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between b5df8e2 and 2f588af.

📒 Files selected for processing (2)

• src/fromager/build_environment.py
• tests/test_build_environment.py

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📝 Walkthrough

Walkthrough

The pull request fixes a bug in BuildEnvironment.get_distributions() where JSON deserialization failures caused an UnboundLocalError instead of propagating the actual exception. A single raise statement was added to re-raise caught exceptions, ensuring callers see the real json.JSONDecodeError. Corresponding test cases verify both the valid JSON path and invalid JSON exception handling.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: re-raising exceptions in get_distributions() when JSON parsing fails.
Description check	✅ Passed	The description clearly explains the problem (UnboundLocalError due to swallowed exception), the solution (re-raise), and links to issue #1023.
Linked Issues check	✅ Passed	The PR fully implements the fix specified in #1023: adds raise after logging to propagate the original exception, and includes two test cases covering valid and invalid JSON scenarios.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the error handling in get_distributions() and adding corresponding tests; no unrelated modifications detected.

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[rd4398]

Looks good to me!