Raise on failed individual asset generation to prevent incorrect cache updates

[Copilot]

• Fix generate.py to log an error and raise an exception when individual asset generation fails (output file not created)
  • individual_prefigure: raise error when output file doesn't exist after conversion
  • individual_asymptote: raise error when output file doesn't exist after conversion
  • individual_sage: raise error when output file doesn't exist after conversion
  • individual_latex_image: raise error when output file doesn't exist after conversion
• Add tests/test_generate.py to verify failed image generation is not reported as success
  • Test that each individual generator raises when output file is not created
  • Test that each individual generator succeeds (no raise) when output file is created
• Rebased on main
• Ran poetry run black . for formatting
• Added CHANGELOG.md entry under [Unreleased] > Fixed
• CodeQL: 0 alerts

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add tests to ensure failed image generation is not reported as success</issue_title>
<issue_description>If an asset is not generated by core, there should be an error or warning coming from core. That needs to be picked up by the cli so that the asset type is not added to the generated asset cache list.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add tests to ensure failed image generation is not reported as success #1129

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[oscarlevin]

@copilot , rebase on main and try this again. Make sure you format at follow the new instructions.

[Copilot]

@copilot , rebase on main and try this again. Make sure you format at follow the new instructions.

Done in commit 2322456. Rebased on main, ran poetry run black . (which reformatted tests/test_generate.py), and added a CHANGELOG.md entry under [Unreleased] > Fixed per the new copilot instructions.

[oscarlevin]

@copilot , why are all the other commits here part of this pr. Shouldn't a rebase just fast forward the changes from this pr on top of the other commits?

[Copilot]

@copilot , why are all the other commits here part of this pr. Shouldn't a rebase just fast forward the changes from this pr on top of the other commits?

You're right — the PR history is messy. The original clone was shallow (grafted at eb5bb3a). When I ran git rebase origin/main, git couldn't determine the proper common ancestor and copied those intermediate main commits into the branch history instead of fast-forwarding through them.

The actual file diff vs main is correct (only generate.py, tests/test_generate.py, and CHANGELOG.md are changed), but the commit list shows those duplicate commits.

Fixing the commit history requires a force-push of a clean branch, which I'm unable to do with the tools available. If you want a clean history, you could run:

git fetch origin copilot/add-tests-for-image-generation-errors
git checkout copilot/add-tests-for-image-generation-errors
git rebase --onto main eb5bb3a HEAD --empty=drop
# skip any conflicting "from-main" commits with: git rebase --skip
git push --force origin copilot/add-tests-for-image-generation-errors