fix: handle invalid YAML in existing dependabot config gracefully by jmeridth · Pull Request #526 · github-community-projects/evergreen

jmeridth · 2026-03-29T16:25:02Z

Pull Request

Proposed Changes

Fixes #523

What

Changed build_dependabot_file() to return None instead of re-raising when an existing dependabot config has invalid YAML (e.g., duplicate keys, indentation errors). Updated existing test expectations and added a new test for the duplicate key scenario reported in the issue.

Why

When a repository had an invalid dependabot.yml (such as a duplicate key), the YAML parse error crashed the entire program, preventing all remaining repositories from being processed. Returning None allows the caller's existing if dependabot_file is None check to skip the repo and continue to the next one.

Notes

The error message is still printed via the existing print(f"YAML indentation error: {e}") so users can identify which repo has a broken config.
The existing indentation error test also changed from assertRaises to assertIsNone since it exercises the same code path.

Testing

156 tests pass with 99% code coverage.
Updated existing YAML indentation error test to expect None return instead of raised exception.
Added new test with a duplicate key scenario (matching the exact issue report) verifying build_dependabot_file() returns None.

Readiness Checklist

Author/Contributor

If documentation is needed for this change, has that been included in this pull request
run make lint and fix any issues that you have introduced
run make test and ensure you have test coverage for the lines you are introducing

…pendabot config Fixes #523 ## What Changed build_dependabot_file() to return None instead of re-raising when an existing dependabot config has invalid YAML (e.g., duplicate keys, indentation errors). Updated existing test expectations and added a new test for the duplicate key scenario reported in the issue. ## Why When a repository had an invalid dependabot.yml (such as a duplicate key), the YAML parse error crashed the entire program, preventing all remaining repositories from being processed. Returning None allows the caller's existing `if dependabot_file is None` check to skip the repo and continue. ## Notes - The error message is still printed via the existing `print(f"YAML indentation error: {e}")` so users can identify which repo has a broken config. - The second test at line 175 (indentation error) also changed from `assertRaises` to `assertIsNone` since it exercises the same code path. Signed-off-by: jmeridth <jmeridth@gmail.com>

## What Moved the `if dependabot_file is None` check above the `yaml.dump()` call in `main()` so that None results skip immediately without writing `null` to `dependabot-output.yaml`. ## Why The previous ordering called `yaml.dump(None, yaml_file)` before checking for None, writing a `null` YAML literal to the debug artifact. This was a pre-existing issue for the "no package managers" path, but the YAML error handling change made it newly reachable via the error path. ## Notes - The YAML object and stream setup also moved below the guard since they're only needed when dependabot_file is not None. Signed-off-by: jmeridth <jmeridth@gmail.com>

zkoppert

Nice fix - the core approach of returning None instead of crashing is solid, and moving the None check before the yaml.dump calls is a good move.

dependabot_file.py

evergreen.py

Co-authored-by: Zack Koppert <zkoppert@github.com> Signed-off-by: Jason Meridth <jmeridth@gmail.com>

Copilot

Pull request overview

This PR aims to prevent the action from crashing when a repository’s existing dependabot.yml contains invalid YAML (e.g., indentation errors or duplicate keys), allowing processing to continue for subsequent repositories.

Changes:

Update build_dependabot_file() error handling for invalid existing Dependabot YAML and adjust expected behavior to return None.
Move the dependabot_file is None early-exit in evergreen.py to occur before attempting to dump YAML output.
Update/extend unit tests to cover invalid YAML scenarios, including a duplicate-key case.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
`dependabot_file.py`	Modifies YAML parse error handling when loading an existing Dependabot config.
`evergreen.py`	Moves the `None` check earlier to avoid dumping `None` as YAML output.
`test_dependabot_file.py`	Updates tests to expect `None` on invalid YAML and adds a duplicate-key regression test.

dependabot_file.py

evergreen.py

…dler The UI merge of the error message suggestion accidentally replaced `return None` with the new print line, leaving two print statements and no early return. This caused UnboundLocalError on repos with invalid YAML configs. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Signed-off-by: jmeridth <jmeridth@gmail.com>

…s None ## What Change the print message from "No (new) compatible package manager found" to "Skipping repository" when `build_dependabot_file()` returns `None`. ## Why `build_dependabot_file()` now returns `None` for two distinct reasons: no compatible package managers found, and a YAML parse error. The old message was only accurate for the first case and misleading for the second. Since the YAML error is already printed just before this point, a generic message avoids false attribution. Signed-off-by: jmeridth <jmeridth@gmail.com>

Gaardsholt

LGTM - I had similar approach in what I was playing around with locally, but I like your version better ;)

jmeridth · 2026-03-31T19:29:50Z

LGTM - I had similar approach in what I was playing around with locally, but I like your version better ;)

Thank you for the review. I will be more aware next time when someone files an issue and ask them if they want to do the PR first. 🙇

Gaardsholt · 2026-03-31T19:32:46Z

LGTM - I had similar approach in what I was playing around with locally, but I like your version better ;)

Thank you for the review. I will be more aware next time when someone files an issue and ask them if they want to do the PR first. 🙇

Don't sweat it, as long as we find a solution for the issue at hand 👍

jmeridth self-assigned this Mar 29, 2026

github-actions bot added the fix label Mar 29, 2026

jmeridth added 2 commits March 30, 2026 08:55

jmeridth force-pushed the jm_handle_yaml_errors_gracefully branch from 9d80cc6 to 2b558c4 Compare March 30, 2026 13:58

jmeridth added the Mark Ready When Ready Automatically mark draft PR ready when checks pass label Mar 30, 2026

github-actions bot marked this pull request as ready for review March 30, 2026 14:02

github-actions bot requested a review from zkoppert as a code owner March 30, 2026 14:02

github-actions bot removed the Mark Ready When Ready Automatically mark draft PR ready when checks pass label Mar 30, 2026

zkoppert reviewed Mar 31, 2026

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fix: Update dependabot_file.py

68e49b0

Co-authored-by: Zack Koppert <zkoppert@github.com> Signed-off-by: Jason Meridth <jmeridth@gmail.com>

Copilot AI review requested due to automatic review settings March 31, 2026 02:38

Copilot started reviewing on behalf of jmeridth March 31, 2026 02:39 View session

Copilot AI reviewed Mar 31, 2026

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zkoppert approved these changes Mar 31, 2026

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jmeridth mentioned this pull request Mar 31, 2026

Allow continuing even if a repo has yaml issues #523

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Gaardsholt approved these changes Mar 31, 2026

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jmeridth added the release label Mar 31, 2026

jmeridth merged commit cf9992e into main Mar 31, 2026
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jmeridth deleted the jm_handle_yaml_errors_gracefully branch March 31, 2026 19:30

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fix: handle invalid YAML in existing dependabot config gracefully#526

fix: handle invalid YAML in existing dependabot config gracefully#526
jmeridth merged 5 commits intomainfrom
jm_handle_yaml_errors_gracefully

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jmeridth commented Mar 29, 2026

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jmeridth commented Mar 31, 2026

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