[cmd/mdatagen] Imports in generated files should match linting requirements

[crobert-1]

Component(s)

cmd/mdatagen

Describe the issue you're reporting

I'm filing this issue as a result of open-telemetry/opentelemetry-collector-contrib#45013

Currently, after generating files using mdatagen, the generated go code must be formatted and the import order must be overwritten (in contrib this means running make generate, make fmt, and make gci.) This solution works, but it means users may forget to run the formatting and gci commands, resulting in improperly formatted go code, or more steps to getting CI/CD green on a PR.

That being said, to handle this in mdatagen could make import logic considerably more complicated, since all imports would need to be known, and blank lines could only be added if a block has imports, etc. I'll defer to code owners to decide if this enhancement is worth the effort, or if we should stick with requiring make fmt and make gci to be run every time after mdatagen.

An alternative solution may just be to somehow built in the make fmt and make gci calls to the mdatagen functionality, but that may also just be another level of complexity.

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[github-actions]

Pinging code owners:

• cmd/mdatagen: @dmitryax

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[crobert-1]

From my comment on the original issue:

this is an impossible request, given that import orders are not consistent across repos. Since mdatagen is in core, the core collector dependencies make up the third group of dependencies (the ones that are replace'd in go.mod. For example, the generated component test file for the otlphttp exporter. The core collector dependencies make up the third block of imports, and are replaced in go.mod. So core has these dependencies in the third block, contrib has them in the second. I'm not sure how mdatagen could properly account for these differences.

Feel free to close this issue if my findings are correct, otherwise this issue could be used to continue investigating if this would be possible.

[dmathieu]

I think not caring about dependencies order in mdatagen, and relying on gofmt to fix them (with a CI check to ensure everything is all right before any merge) is the best solution here.
As you mention, setting this up in mdatagen would add a lot of complexity, for something that's already handled.