Add errgroupcheck linter

[alexbagnolini]

errgroupcheck analyzes code and reports any usage of golang.org/x/sync/errgroup that is missing any call to the Wait() func.

All the examples reported in the errgroup documentation showcase the correct usage of the Wait() func to wait for all the coroutines to complete before proceeding.

Missing the Wait() call allows the code to compile just fine, but yields unexpected results due to the coroutines running without any wait for termination.

[boring-cyborg]

Hey, thank you for opening your first Pull Request !

[CLAassistant]

All committers have signed the CLA.

[ldez]

In order for a pull request adding a linter to be reviewed, the linter and the PR must follow some requirements.

• The CLA must be signed

Pull Request Description

• It must have a link to the linter repository.
• It must provide a short description of the linter.

Linter

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• It must have a valid tag, ex: v1.0.0, v0.1.0.
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• It must not have false positives/negatives (the team will help to verify that).
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The Linter Tests Inside Golangci-lint

• They must have at least one std lib import.
• They must have integration tests without configuration (default).
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.golangci.next.reference.yml

• The file .golangci.next.reference.yml must be updated.
• The file .golangci.reference.yml must NOT be edited.
• The linter must be added to the lists of available linters (alphabetical case-insensitive order).
  • enable and disable options
• If the linter has a configuration, the exhaustive configuration of the linter must be added (alphabetical case-insensitive order)
  • The values must be different from the default ones.
  • The default values must be defined in a comment.
  • The option must have a short description.

Others Requirements

• The files (tests and linter) inside golangci-lint must have the same name as the linter.
• The .golangci.yml of golangci-lint itself must not be edited and the linter must not be added to this file.
• The linters must be sorted in the alphabetical order (case-insensitive) in the lintersdb/builder_linter.go and .golangci.next.reference.yml.
• The load mode (WithLoadMode(...)):
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Recommendations

• The file jsonschema/golangci.next.jsonschema.json should be updated.
• The file jsonschema/golangci.jsonschema.json must NOT be edited.
• The linter repository should have a readme and linting.
• The linter should be published as a binary (useful to diagnose bug origins).
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• use main as the default branch name.

---

The golangci-lint team will edit this comment to check the boxes before and during the review.

The code review will start after the completion of those checkboxes (except for the specific items that the team will help to verify).

The reviews should be addressed as commits (no squash).

If the author of the PR is a member of the golangci-lint team, he should not edit this message.

This checklist does not imply that we will accept the linter.

[Antonboom]

Another yet case for uncalled

#3348

[alexbagnolini]

Can you help me understand this?

If the linter has a configuration, the exhaustive configuration of the linter must be added (alphabetical case-insensitive order)

• The values must be different from the default ones.
• The default values must be defined in a comment.
• The option must have a short description.

The only config available is to enable / disable the sole rule currently implemented.

Should I change the Default to be false and leave the value to true, or the opposite?

  errgroupcheck:
    # Check if any sync.errgroup.Group instance is missing a call to the Wait() func.
    # Default: true
    require-wait: true

[ldez]

The "# Default:" should be the default value.
The value of the option should not be the default value.

    # Default: true
    require-wait: false

[Crocmagnon]

Does the longer work for errgroups stored as struct attribute?
I have a use case where I’m creating a struct containing an errgroup in a "constructor", starting goroutines in a method of the struct and waiting in a third. What would that look like?