[Bug]: prevalent stdout/stderr stream confusion

[michaelfig]

Is there an existing issue for this?

• I have searched the existing issues

What happened?

When using output from appd keys show -a MYKEY --keyring-backend=test in a script, I had flaky results. After spending considerable time narrowing it down, the problem was sometimes the output would be:

agoric1abcdefghi12345

and sometimes it was:

Successfully migrated key MYKEY.
agoric1abcdefghi12345

CLIs that are designed to produce machine-readable output should not frustrate attempts to consume stdout with corner-cases that interrupt the standard behaviour. This goes much further than just the "Sucessfully migrated key..." message in cosmos-sdk/crypto/keyring/keyring.go. I would expect a careful audit of all uses of fmt.Print* in the SDK, and where the output is not usefully capturable by a calling program, it should be directed at stderr instead.

I recognise that the converse also needs to be true: if writes to os.Stderr are usefully capturable by a calling program, they should be directed at stdout.

Cosmos SDK Version

main

How to reproduce?

Search the SDK for fmt\.Print, and observe its use within libraries such as crypto.