fix: don't generate on error if backup file doesn't exists

[JrCs]

Signed-off-by: JrCs 90z7oey02@sneakemail.com

Summary

If the replacement (sed) is not done the backup file isn't create and the rm command return on error.
With rm -f no error is generated even if the file doesn't exists.

[Stratus3D]

Thanks for the PR @JrCs! Are there any open issues reporting this problem? What OS and version are you on? Can you provide the output from asdf info so we can understand what environment(s) experience this issue?

[jthegedus]

@JrCs could create a test that reproduces this issue which we can then use to validate that this change is necessary?

[JrCs]

@jthegedus if you call asdf with a bash script that use a set -u asdf will stop if it can't remove the backup file.
I don't have another test for this.

[jthegedus]

Thanks for sharing, asdf is not yet compatible with -u. There's probably a better way for us to handle the error than performing -f on rm. Can you look into alternatives?

[Stratus3D]

@JrCs , do you know why that happens? set -u causes bash to exit when an unset variable is encountered. I wouldn't expect these changes to affect anything related to that as no new variables are used. Am I missing something here?

[JrCs]

@Stratus3D i use also set -e to causes bash to exit when a command exit with a code different than 0.

[Stratus3D]

@JrCs can you share a little more about how you invoked asdf after setting set -e? I'm curious how this setting outside of the asdf codebase is affect it.

[JrCs]

@Stratus3D easy: do a set -eu in your current shell then call asdf.
For my use case the set -e is done by my CI pipeline for the current shell.

[Stratus3D]

Hmm... I am unable to reproduce this issue on OSX using Zsh:

$ set -e
$ asdf local lua 5.3.3
$ asdf reshim

Both commands succeed without any issues with this fix.

This is not a big deal to me, as I'd eventually like to move to having set -e set inside asdf, and these changes are one step closer to making that possible. Thanks for the PR @JrCs ! I am merging now.