[Doc] Moving file while using --new-from-rev

[amenasria]

Welcome

• Yes, I'm using a binary release within 2 latest major releases. Only such installations are supported.
• Yes, I've searched similar issues on GitHub and didn't find any.
• Yes, I've read the typecheck section of the FAQ (https://golangci-lint.run/usage/faq/#why-do-you-have-typecheck-errors).
• Yes, I've tried with the standalone linter if available (e.g., gocritic, go vet, etc.). (https://golangci-lint.run/usage/linters/)

Description of the problem

We recently used the new-from-rev key in our configuration to enable revive on our large codebase to avoid having to fix all the errors directly. It was really practical at first !

One major caveat of new-from-rev imo is moving files. Let's say I have a legacy file hello.go with 100 lints (i.e linter errors). The new-from-rev parameter will silence them all. But if I rename this file to hello_world.go or move it to another folder then all the lints will rise again.

I think this should be mentioned in https://golangci-lint.run/usage/faq/#how-to-integrate-golangci-lint-into-large-project-with-thousands-of-issues to make people aware of the cost of relying on new-from-rev.

Version of golangci-lint

$ golangci-lint --version
golangci-lint has version v1.54.2 built with go1.21.5 from (unknown, mod sum: "h1:oR9zxfWYxt7hFqk6+fw6Enr+E7F0SN2nqHhJYyIb0yo=") on (unknown)

Configuration

https://github.com/DataDog/datadog-agent/blob/fcb19ce078e7969d285565beec5d374c5fd623e1/.golangci.yml

Go environment

$ go version && go env
go version go1.21.5 darwin/arm64

Validation

• Yes, I've included all information above (version, config, etc.).

[ldez]

Hello,

It feel expected: new-from-rev will use a git diff, so when you move a file, this file is inside the diff.

I don't know how to improve the documentation about that 🤔

[amenasria]

Hey, sorry for the late response I missed the notification !

It feel expected: new-from-rev will use a git diff, so when you move a file, this file is inside the diff.

I agree that this is expected because of the use of git diff, the thing is it's not mentioned anywhere that it's using a git diff, I understood it while playing with it. This is imo what hides the moving-file-trap.

I don't know how to improve the documentation about that 🤔

I think I would expect something like:

Warning: the `--new-from-rev: REV` key works by running a `git diff` between the git revision REV and the current commit.

Renaming / moving a file will hence reveal all the silenced lints in this file.

WDYT? Does this seem reasonable to you?

Thanks for taking the time to answer !