Displaying multiline data correctly in _ynh_app_config_show

[oleole39]

The problem

As of YNH 12.1.3, if a custom getter in an app returns a multiline string, it will eventually get displayed in the config panel input box (e.g. in text box) as a single line string.

Solution

The proposed solution here is to change echo to echo -e in _ynh_app_config_show() helper so that it allows interpretation for newline characters.
Thus, multiline string output by the custom getter should be as such: line1\n\nline2\n\nline3 (single newline character is not enough, likely due to other layers of code (not investigated in this PR but which remind me of YunoHost/issues#2501).
That way it will get displayed in the config panel (tested for text input only) as:

line1
line2
line3

PR Status

Ready to merge as I don't believe it could impact negatively other custom getters.
Note that I am not very sure of when is actually triggered the portion of the modified helper after else instruction, maybe double newline would be too much here.

TODO: update the doc depending on whether that PR is accepted: https://doc.yunohost.org/en/packaging_config_panels

How to test

Cf. custom getter for marl_ynh config panel: https://github.com/YunoHost-Apps/marl_ynh/blob/31fbaad1c035630ed541361975c8af4d09025b8b/scripts/config#L76

You can install the app and then run yunohost app config get marl --full --debug to see whether YAML output includes multiline or singleline entry for archives_paths parameter.

[Salamandar]

Actually that might break scripts that grep the output, as well as scripts that parse it as yaml.

[oleole39]

Actually that might break scripts that grep the output, as well as scripts that parse it as yaml.

Not fully clear for me. You mean (some) apps scripts, right ? Would you have an example in mind ?