Use errcheck from main repo instead of golangci-lint fork

[SVilgelm]

Closes #1274
Closes #1194
Closes #882
Closes #959

kisielk/errcheck@8050dd7...master
golangci/errcheck@8050dd7...master

Depends on:

• Move errcheck package out of internal kisielk/errcheck#185
• Add SelectorName in UncheckedError kisielk/errcheck#197

[sayboras]

Mark as draft PR to avoid showing up in review list.

[leventov]

Hello @SVilgelm @sayboras, maybe we could reignite this PR because kisielk/errcheck#185 is now merged?

[ldez]

The previous exclusion rule (Error return value of .((os\.)?std(out|err)\..*|.*Close|.*Flush|os\.Remove(All)?|.*print(f|ln)?|os\.(Un)?Setenv). is not checked) will not work because of the change of the value of UncheckedError.FuncName

The current output:

scripts/expand_website_templates/main.go:61:17: Error return value of `(*os.File).Write` is not checked (errcheck)
        os.Stdout.Write([]byte{})
                       ^
scripts/expand_website_templates/main.go:62:14: Error return value of `os.RemoveAll` is not checked (errcheck)
        os.RemoveAll("/tmp/example")
                    ^
scripts/expand_website_templates/main.go:63:11: Error return value of `os.Setenv` is not checked (errcheck)
        os.Setenv("EXAMPLE", "FOO")
                 ^
scripts/expand_website_templates/main.go:153:23: Error return value of `(io.Closer).Close` is not checked (errcheck)
        defer resp.Body.Close()
                             ^

The output with the PR:

scripts/expand_website_templates/main.go:61:17: Error return value of `os.Stdout.Write` is not checked (errcheck)
        os.Stdout.Write([]byte{})
                       ^
scripts/expand_website_templates/main.go:62:14: Error return value of `os.RemoveAll` is not checked (errcheck)
        os.RemoveAll("/tmp/example")
                    ^
scripts/expand_website_templates/main.go:63:11: Error return value of `os.Setenv` is not checked (errcheck)
        os.Setenv("EXAMPLE", "FOO")
                 ^
scripts/expand_website_templates/main.go:153:23: Error return value of `resp.Body.Close` is not checked (errcheck)
        defer resp.Body.Close()
                             ^

golangci-lint/pkg/config/config.go

Lines 39 to 46 in 306816e

	var DefaultExcludePatterns = []ExcludePattern{
	{
	ID: "EXC0001",
	Pattern: "Error return value of .((os\\.)?std(out|err)\\..*|.*Close" +
	"|.*Flush|os\\.Remove(All)?|.*print(f|ln)?|os\\.(Un)?Setenv). is not checked",
	Linter: "errcheck",
	Why: "Almost all programs ignore errors on these functions and in most cases it's ok",
	},

The main impact is on os.Stdout.* and os.Stderr.* calls.

This will also impact the users that use custom exclusion rules.

[ldez]

I don't see many solutions 😢

1. We drop the exclusions rule, but I think it's not a good idea.
2. We add UncheckedError.Line into the message, but Line contains the real line of code.

In all the cases, it's a breaking change.

[SVilgelm]

@ldez Here is the PR to original repo: kisielk/errcheck#197
to have a backward compatible name in the message

so it should solve the problem with dropping the exclusions rule

[SVilgelm]

@golangci/team Please review, it's still blocked until a new release of the errcheck
But the PR with backward compatible names is merged and this PR is ready for review

[ldez]

LGTM