Update askpass.py user interface

[wjk]

This PR does two things:

• Update all copies of askpass.py to the version from the version in the ISO repo, albeit with one change: a colon is now present after “Password”.
• The package downloader stub scripts now set SUDO_ASKPASS_TEXT.

[probonopd]

Thanks @wjk.

Since helloSystem now has /usr/local/bin/askpass, I was thinking of retiring all other copies. What do you think?

Also, let's avoid untranslated English-only text wherever possible, pending https://github.com/helloSystem/Utilities/issues/46#issuecomment-787431844.

Until we have found an easy way to manage translations for PyQt applications, I think "Password: _____" is better than "(Long English-only text): _____"-

[wjk]

I created multiple copies of àskpass.py because I was trying to follow the AppImage philosophy of bundling all implementation-detail dependencies. I’ll leave it to your judgment if you want me to remove them and use the system copy. As for the dialog text, please see https://github.com/helloSystem/Utilities/issues/53#issuecomment-799646645; we decided that the calling process is responsible for localizing the SUDO_ASKPASS_TEXT string.

I would also like to invite your attention to the babel package. Among other useful tools, this package includes a pure-Python *.po file parser. It parses plain-text po files into the same type of data structure that would be output by loading a compiled *.mo binary file. I could wrap this library into an API resembling the gettext standard library module, and distribute the *.po files within the application bundles. Sound good to you?

[probonopd]

I could wrap this library into an API resembling the gettext standard library module, and distribute the *.po files within the application bundles. Sound good to you?

If this works with halfway reasonable code size and runtime performance overhead, then this would rock :+1: So I would highly appreciate a proof-of-concept.

AppImage philosophy of bundling all implementation-detail dependencies

"... that are not part of the base system". So this one is a close call, and I am still a bit undecided myself. It depends on whether we think that anyone outside of helloSystem will want to use those applications.

[wjk]

that are not part of the base system

According to the “Note to distributors” page in your documentation, these apps are not intended to be used outside of helloSystem as-is. Therefore, the askpass script can indeed be assumed to be part of the base system. I will therefore remove the local copies. I will submit my gettext POC in another branch. Thanks!

[probonopd]

Agree that we should treat askpass as being part of the base system. However I think we should not hardcode the path but rely on SUDO_ASKPASS being supplied by the system in this case. (I have an experimental helloDesktop-on-Linux system for research purposes where it points to a different absolute path, for example.)

[wjk]

@probonopd I can certainly inherit the value for SUDO_ASKPASS from the parent process’s environment, but then what do we do if it is unset? In that case, sudo would prompt for a password on its stdin and block forever since nothing is connected to it.

[probonopd]

We could

• Search for askpass on the $PATH if SUDO_ASKPASS is unset
• Show an error dialog saying that $SUDO_ASKPASS must be set