Can include/exclude regex patterns be handled?

[jhlegarreta]

I am wondering whether regex patterns that have both include/exclude parts are correctly handled.

I would like to be able to mark all files whose path matches a pattern with a label, but to avoid apply a different label to files that share only part of the path.

As an example, I have a label named area:Book that I'd like to apply to all *.tex files under the SoftwareGuide/Latex path:

area:Book:
  files:
    - "SoftwareGuide/Latex/*.tex"

At the same time, I have a label named type:BookStyle that should apply to all files under the Latex path, but not to the files under SoftwareGuide/Latex. Using the pattern below:

type:BookStyle:
  files:
    - "Latex/*"

will add both labels to a file like SoftwareGuide/Latex/Appendices/CodingStyleGuide.tex added in a commit.

I am wondering whether modifying the second rule to

type:BookStyle:
  files:
    - "^Latex/[^/]*"

would avoid applying the type:BookStyle label to SoftwareGuide/Latex/Appendices/CodingStyleGuide.tex.

Cross-referencing:
InsightSoftwareConsortium/ITKSoftwareGuide#167

Thanks and sorry to ask a question by opening an issue.

[jhlegarreta]

Tested in a test repository of my own, and it looks like the mentioned regex pattern is not appropriately dealt with:

 type:BookStyle:
  files:
    - "^Latex/[^/]*"
2021/11/21 00:47:15 Unable to unmarshall legacy config: yaml: unmarshal errors:
  line 3: cannot unmarshal !!seq into labeler.LabelMatcher
  line 5: cannot unmarshal !!seq into labeler.LabelMatcher
  line 7: cannot unmarshal !!seq into labeler.LabelMatcher
  line 9: cannot unmarshal !!seq into labeler.LabelMatcher
  line 11: cannot unmarshal !!seq into labeler.LabelMatcher
  line 15: cannot unmarshal !!seq into labeler.LabelMatcher

Looks like the regex cannot be read properly in here (?):
https://github.com/srvaroa/labeler/blob/master/cmd/action.go#L102

Does addressing this look doable @srvaroa ? Thanks for the effort.

[akutz]

Mentioned in vmware-tanzu/vm-operator#50 (review) (this was not added automatically for some reason)

[srvaroa]

Hi, sorry I totally missed this issue. I will take a closer look into this in the coming days. Thanks for reporting.

[philippwaller]

@jhlegarreta, @akutz: I believe this thread might be helpful to you:

As this GitHub Action is written in Go (Golang), handling regular expressions (Regex) requires a bit of extra care. Specifically, you'll need to escape special characters using double backslashes. This is because the backslash in Go strings is an escape character and therefore must be escaped itself.
Here's an example that should work:

- label: "File"
  files:
    - ".*\\/subfolder\\/.*\\.md"

To clarify this, I've submitted PR (#129) that updates the documentation accordingly.

Originally posted by @philippwaller in #50 (comment)

@srvaroa: Presumably, this is about the same issue.

[srvaroa]

Yeah, I will add a couple of test cases to prove the examples provided above.

[jhlegarreta]

@philippwaller thanks for the heads-up; @srvaroa thanks for the documentation; I will try to test it as time permits.

[akutz]

It is unclear if this actually adds support for excluding file patterns. The negate option does not really work either. We need a way to express:

Apply this label if CONDITION except for GENERATED FILES

Essentially we want to apply labels based on the size of the change, but the size should not be calculated based on changes related to generated content.

[srvaroa]

@akutz the size condition supports an exclude-files option for this purpose. Right now this only supports explicit exclusions but I could turn it into a regex if that's what you need.

[akutz]

That would be great, thank you! Please see https://github.com/vmware-tanzu/vm-operator/blob/3ebc8097d391c2356073d7c327b1b0f72d44f5b0/.github/workflows/pr-labeler.yml#L12-L33 for more information.

[srvaroa]

@jhlegarreta @akutz this should deal with the exclusions in the Size condition. There is an example that should be reasonably understandable in the tests. Let me knot if this looks good for you and I'll get this released asap.

[srvaroa]

@jhlegarreta I have added a couple of tests to verify the conditions you quoted above. It looks like the expressions work correctly after escaping the characters.

Let me know if that solves your use case.

Tests here -> https://github.com/srvaroa/labeler/pull/132/files#diff-133334d6ef7baf3e8c0bc80d52a8a7c185e1fca8345190d244e4c7c66ee89925R537

[srvaroa]

I will close this for now, but @jhlegarreta do let me know if your issue is still not solved.