Errors should go to stderr

[danp]

I accidentally ran:

$ heroics-generate -h "Content-Type: application/json" ... > x.rb

when I should have used -H. The error output went to stdout and got redirected to x.rb.

[schneems]

I'm still seeing this behavior:

$ bin/heroics-generate -h "Content-Type: application/json" > out.tmp
⛄ 2.7.1 🚀  ~/Documents/projects/tmp/heroics (schneems/fix-heroku-api)
$ cat out.tmp
Usage: heroics-generate module_name schema_filepath url
       heroics-generate configuration-file-path.rb
# Params only allowed when using the first form:
    -h, --help                       Display this screen
    -H, --header [HEADER]            Include header with all requests
    -c, --cache-dir [PATH]           Content cache directory (~ is automatically expanded)

From an interface perspective, I think it would be more clear and less error-prone if the command took an explicit file input, something like:

$ heroics-generate MyApp schema.json https://api.myapp.com --output=client.rb

Otherwise I agree that putting warnings and errors to stderr instead of stdout helps clarify issues.

[tkenvin]

I think that this is probably correct behaviour because -h or --help is supposed to print the usage to stdout and exit with 0. In contrast try to provide a valid option such as -c or -H without the required argument or an invalid option such as -k, in these cases error messages are sent to stderr and a non-zero exit value is returned.

What I don't understand, and this may be my fault, is when the usage output says:

# Params only allowed when using the first form:

when this doesn't/shouldn't apply to -h.