golint: add flag to ignore vendor dirs

[dvyukov]

A typical usage for a project is: golint ./...
Scanning all vendored packages creates noise,
takes time and is usually not useful.

Add -vendor flag that controls inclusion of vendor
dirs during ... expansion.

Note: this changes default behavior as the default
value for the flag is false. This is debatable.
The rationale for false is:

• go tool at tip ignores vendor during fmt and test
• people generally don't want to change vendored
  packages, especially for style

[mvdan]

If the go tool always ignores vendor/ when walking packages, shouldn't golint do the same without a flag?

[dvyukov]

@mvdan On second thought, I think you are right.
go fmt/test has an escape path. It won't check vendor on go fmt ./..., but it will check vendor on go fmt ./vendor/.... I.e. it does not enter into vendor dir during walk (need to double check actual code).
This will work for golint as well. And as far as we have an escape path, not having a flag seems fine.

[mvdan]

Yeah, vendor/ is only ignored when its parent is walked. This works really well without an extra flag, and it also keeps consistency between linters and the go tool itself.

[jbergstroem]

Not necessarily the way forward, but a workaround should you use glide:

$ golint $(glide novendor)

[dsnet]

Change seems fine to me, but let's avoid the flag.

[mholt]

Any update on this? Go 1.9 is released and golint ./... is causing all sorts of havoc in my CI logs because there's about 9000 warnings in the vendor folder... but all other go commands ignore the vendor folder.

[Horgix]

@mholt : was browsing the PRs in this repo so I'm not aware to the context of this one, but personally since golint doesn't ignore the vendor folder I'm running this:

golint `go list ./... | grep -v /vendor/`

Note the backquotes that make it run in a subshell (you could also use $(...))

[mholt]

@Horgix Thanks; yeah, I have a bash script that can work around it, but it's not as pretty on Windows CI...

[xgfone]

Since golint checks the packages in vendor, the intellisense is a little slow.

I think that it should not check the packages in vendor. In general, they are not our own codes. It is similar to node_modules in NodeJS.

[nathany]

In light of the changes in Go 1.9, I think the default behaviour for golint ./... should be to ignore vendor. Please see #320.

[mholt]

@nathany To be clear, it looks like this PR does cause vendor to be ignored by default; the title is a bit misleading, since the flag actually "enables" vendor folder lint checking.

[dvyukov]

Feel free to take over.

[ifiok]

golint `go list ./... | grep -v /vendor/`

This worked for me.

[SAG786]

golint go list ./... | grep -v /vendor/

This worked for me!