Error message about host not existing is printed to stdout

[bfirsh]

The error message about the host not existing is printed to stdout, so this fails silently:

$ eval $(docker-machine env fdshkjlfsd)
$ 

[dave-tucker]

+1, it's not just the host not existing, but any error message
e.g FATA[0000] Unexpected error getting machine url: exit status 255
This happened to me today and I ended up running containers on the wrong docker host as I had assumed that the command had completed successfully :(

[ehazlett]

@tianon is there anything we can do here with the eval? If machine exits non-zero would that cause the eval to show something?

[nathanleclaire]

@bfirsh @dave-tucker @ehazlett This should now be fixed, and if things that need to "leak" their output from a subshell don't do so it's a bug. See: #1217 which cleans up the remaining thing we missed on this.

This was a huge reason we did the logging refactor: To clean up the granularity of what we print to STDOUT and STDERR.

Today on master I get:

$ eval $(docker-machine env fdshkjlfsd)
Error: Host does not exist: fdshkjlfsd

[tianon]

@ehazlett yeah, what Nathan said -- exit code for eval isn't used, but stderr is not captured at all so it's definitely the appropriate place for error messages

[ehazlett]

@nathanleclaire @tianon perfect. closing as this looks correct.