"cargo help test" output should go to stdout

[tromey]

Currently, cargo help test output goes to stderr. This makes it unnecessarily difficult to pipe the output through a pager. Furthermore, this isn't an error situation -- the command exists to print the help, so it seems to me that it ought to go to stdout. (If it's any use, this is a longstanding GNU convention for tools as well; so many if not most core Linux utilities work this way.)

[alexcrichton]

Definitely sounds like a bug!

[tromey]

Perhaps the cause is actually in docopt.

[tromey]

No, docopt seems to do this properly at first read.

[tromey]

Changing exit_with_error to print to stdout in the non-fatal case worked for me, but I wonder if this needs a test.

[matklad]

Furthermore, this isn't an error situation

To give some historical context, we use stderr in Cargo not only for errors, but for all "human" content, so that tools can safely parse stdout as JSON.

This definitely should not apply to cargo --help though!

[tromey]

I added a test to tests/search.rs but I can't tell from cargo test whether or not it is actually running. I guess I can try hacking in a println and see if that does anything.

[tromey]

Yeah, that doesn't seem to run.

[tromey]

Aha, I figured out how to run it by hand.