Replace ioutil with io and os

[ahrtr]

The ioutil package has already been deprecated in golang 1.16, please see go1.16#ioutil. So we need to replace all the ioutil with os and io.

The ioutil used in yaml or txt files are not updated in this PR.

[boring-cyborg]

Hey, thank you for opening your first Pull Request !

[CLAassistant]

All committers have signed the CLA.

[bombsimon]

Thanks! LGTM

[ldez]

I just want to be precise: the ioutil package is not really deprecated, there is no depreciation defined in this package.

The Go team recommends using the new implementation in the new code, but they don't recommend removing it from the existing code (they say nothing about existing code).

... we encourage new code to use the new definitions in the io and os packages.
https://golang.org/doc/go1.16#ioutil

---

For me, the code in the testdata package must keep, at least for now, the use of ioutil.

[bombsimon]

What do you mean, the linked titel literally says "Deprecation of ioutil"? However, what deprecated means may vary, it's nothing guaranteeing deprecated tools to stop working.

Russ Cox explains this on twitter:

Seeing discussion of io/ioutil deprecation in various places.

To be clear: in Go, “deprecated” means only “there is a better, preferred way.” It does not mean “will break in the future.”

Today’s programs using ioutil.ReadFile and friends will keep working forever.

I see no reason not to use the "better, preferred way" just because Go guarantees it won't stop working.

For me, the code in the testdata package must keep, at least for now, the use of ioutil.

Do you mind elaborate on why this is a must for you?

[ldez]

What do you mean

I mean there are literally no depreciation comments in the package ioutil.

It was just to be clear about the real context of this PR.

Do you mind elaborate on why this is a must for you?

As the package ioutil will still be here, I think it's a good idea to keep some tests that use this package. And some tests are explicitly only for this package.

FYI the CI fails because of the changes in the testdata package.

[bombsimon]

As the package ioutil will still be here, I think it's a good idea to keep some tests that use this package.

Thanks for explaining. I was under the impression that it wouldn't still be here but maybe you mean in general in the Go ecosystem.

FYI the CI fails because of the changes in the testdata package.

Yeah I didn't dig into the root cause but surely there must be a way to make testdata work without iotuil I hope.

But if this isn't something that should change in golangci-lint I think it makes more sense to close this PR and keep the usage in testdata. If we want to make this change in the future it's probably easier to just file a new PR. WDYT?

[ldez]

I was under the impression that it wouldn't still be here but maybe you mean in general in the Go ecosystem.

Yes, it will still be in Go code base and Go libraries.

Yeah I didn't dig into the root cause but surely there must be a way to make testdata work without iotuil I hope.

the testdata package contains files used to test the linters. The goal of those files is to evaluate linters, then they always "work".

But if this isn't something that should change in golangci-lint I think it makes more sense to close this PR and keep the usage in testdata. If we want to make this change in the future it's probably easier to just file a new PR. WDYT?

It's not what I'm trying to say.

There are a few weeks we dropped go1.15 constraints in the CI (2021-10-17) and updated the minimal requirement to go1.16 (2021-10-20 #2041 (comment)).

Yes, now we can use the ioutil package replacements through the io and os packages.

The linters are here to evaluate all the Go code even ioutil related code, and some tests are here only for this package (ex: func TestErrcheckIgnoreIoutil())

So my opinion is to remove ioutil from the golangci-lint code but not in the existing linter test files.

[ahrtr]

Thanks. I just reverted all changes in testdata package.

[ldez]

LGTM

[golangci-automator]

Hey, @ahrtr — we just merged your PR to golangci-lint! 🔥🚀

golangci-lint is built by awesome people like you. Let us say “thanks”: we just invited you to join the GolangCI organization on GitHub.
This will add you to our team of maintainers. Accept the invite by visiting this link.

By joining the team, you’ll be able to label issues, review pull requests, and merge approved pull requests.
More information about contributing is here.

Thanks again!