go: prints module lookup information into error stream

[raydac]

What version of Go are you using (go version)?

go version go1.11.1 linux/amd64

Does this issue reproduce with the latest release?

yes

What did you expect to see?

go prints messages about module lookup into stdout because it is not an error

What did you see instead?

go prints messages about module lookup into stderr
cache.go contains such code

if !QuietLookup {
			fmt.Fprintf(os.Stderr, "go: finding %s %s\n", r.path, rev)
		}

if !QuietLookup {
			fmt.Fprintf(os.Stderr, "go: finding %s latest\n", r.path)
		}

[mvdan]

It's very common for log messages to go to stderr. In fact, if they went to stdout, they would get mixed with a command's normal output, which the user might need to read and use.

Imagine go list some.package/path/.... If that command has to download a module, the standard output would be more than just the resulting package paths.

So I'm not sure how you'd send all log messages to stdout without breaking cmd/go in a dozen ways.

[mvdan]

To further prove my point, see how the log package defaults to os.Stderr: https://golang.org/src/log/log.go?s=#L73

[raydac]

ok, as I see it is some feature, not a bug, so I will find workaround in my tool, thanks