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moon v1.10 - Mid-year quality of life improvements

· 4 min read
Miles Johnson

Instead of launching a large feature this release, we're focusing on quality of life and developer experience improvements.

Quality improvements

In the past 6 months, we've released over 16 versions of moon, with our official v1.0 release among them. This is extremely impressive and we're very proud of the progress we've made. To continue this trend, we'll be starting a new initiative that will land quality of life improvements (instead of major features) every 6 months, starting with this release!

Potential breaking changes

While APIs haven't changed, we have introduced some fixes for edge case that could be considered breaking, but for the most part, these changes probably won't affect you. With that being said...

The first fix is that tasks configured with the same outputs location (including glob overlap) will now error. This is extremely problematic for caching and hydration, as multiple tasks all writing to the same output will inflate the tarball, and cause unwanted side effects. To demonstrate this, the following is now an error:

command: 'foo build'
- 'dist'

command: 'bar compile'
- 'dist'

The other fix, which primarily applies to moon ci and moon check, is that a target will be skipped if one of its dependencies failed or has also been skipped. Previously the target would attempt to run and most likely fail since it relied on artifacts from its dependencies (which don't exist). Another benefit of this change is that runs should be much faster, as we're not wasting time running targets that we know will fail, which is great for CI.

Ignore hashing input files

We're introducing 2 new settings to .moon/workspace.yml that'll provide more control over the hashing flow, hasher.ignorePatterns and hasher.ignoreMissingPatterns.

The ignorePatterns setting can be used to entirely ignore a file (using glob patterns) from being hashed, and in turn, exclude it as an input source. For example, say we want to ignore all image files.

- '**/*.{png,svg}'

The ignoreMissingPatterns setting pairs with hasher.warnOnMissingInputs. When enabled, moon will log a warning to the terminal that an input is missing. This is useful for uncovering misconfigurations, but can be quite noisy when inputs are truly optional. This new setting can be used to filter these warnings.

warnOnMissingInputs: true
- '**/.eslintrc.*'
- '**/*.config.*'

Customize base and head revision

The moon ci command has always supported customizing the Git base and head revisions through the --base and --head options respectively. This was a requirement for running CI effectively, by comparing across branches or commits. However, the moon run did not support this, as this command was designed to primarily be run locally, but it turns out, y'all are using it in CI too!

To improve the effectiveness of moon run in CI, we've made the following improvements, all of which require the --remote option to be passed.

  • Added support for MOON_BASE and MOON_HEAD environment variables, for customizing the base and head revisions respectively (also supported in moon ci). If not defined, will use the default branch and HEAD.
  • When the current branch is the default branch, the base revision will be the previous commit. Useful for commits landing on master/main.

New debugging a task guide

Running tasks is the most common way to interact with moon, so what do you do when your task isn't working as expected? Diagnose it of course! However, diagnosing the root cause of a broken task can be quite daunting:

  • Is configuration wrong?
  • What about inheritance? Or merging?
  • Is the task platform correct?
  • Were tokens expanded correctly?
  • What about variable substitution?
  • So on and so forth...

To help answer these questions, we're excited to publish an in-depth guide for debugging a task! These steps are the same steps we use internally to diagnose reported issues, or help the Discord community. We hope you find this guide extremely beneficial!

Other changes

View the official release for a full list of changes.

  • Updated moon ci to include a summary of all failed actions.
  • Updated the run report to include stderr/stdout for all attempts.