Include instructions after src action exec

[ryanslade]

Add some instructions to src action exec when everything went well and we print a patch to stdout.

Print instructions to STDERR after the json has been dumped.

[mrnugget]

A thought I had: maybe we should rethink dumping the patch to stdout and instead use a default location, like ./patches.json, that can be overwritten with -o. The message is then something like "Patches saved to patches.json. Use 'src action patchset create-from-patches -f patches.json` ..."

[ryanslade]

If we make creating a file the default do we still want to handle the case where they pipe the output to create patches? eg:

src actions exec -f ~/run-gofmt.json | src campaign patchset create-from-patches

We could check if stdout is pointing at a pipe 'tee' output there too in that case?

[mrnugget]

We could check if stdout is pointing at a pipe 'tee' output there too in that case?

I think that's a good default, yes.

• If -o filename is given, write to filename.
• If no -o filename is given and stdout is not a pipe, write to patches.json.
• If no -o filename is given and stdout is a pipe, write to pipe.

[mrnugget]

@ryanslade if I understand it correctly, #214 did only include the "print to default" file part of this ticket, but not "print instructions", right?

[ryanslade]

Yep, working on the instructions now