Bug 930401 – app-misc/mc: In subshell mode, it is not understood that PROMPT_COMMAND may be an array

• Product: Gentoo Linux
• Status: CONFIRMED ---

[Description kfm 2024-04-22 00:52:07 UTC]

Presently, Midnight Commander initialises interactive instances of bash in such a way that it fails to acknowledge that it is possible for PROMPT_COMMAND to be an array, as is supported since bash 5.1. This is material to Gentoo because >=bash-5.1_p16-r8 and >=bash-5.2-p26-r1 do initialise the variable as an array. Besides which, anyone might do the same in their own ~/.bashrc file.

I shall attach a patch that I think is suitable for Gentoo, whose commit message will contain a detailed rationale.

[Comment 1 kfm 2024-04-22 00:53:46 UTC]

Created attachment 891294 [details, diff]
mc-4.8.31-clear-PROMPT_COMMAND.patch

[Comment 2 kfm 2024-04-22 01:06:04 UTC]

To comment further, upstream ought to be doing something like this:

if eval '[[ ${PROMPT_COMMAND@a} == *a* ]]' 2>/dev/null; then
	PROMPT_COMMAND+=('mc crap goes here')
else
	PROMPT_COMMAND+=';mc crap goes here'
fi

I maintain that the attached patch is likely the better solution for Gentoo, however.

[Comment 3 kfm 2024-04-22 01:16:37 UTC]

There are times at which I wish I could edit comments. Rather, upstream could fix it from their perspective by doing something like:

if eval '[[ ${PROMPT_COMMAND@a} == *a* ]]' 2>/dev/null; then
	PROMPT_COMMAND+=('mc crap goes here')
else
	PROMPT_COMMAND+=${PROMPT_COMMAND+$PROMPT_COMMAND$'\n'}'mc crap goes here'
fi