Re: [PATCH] completion: fix prompt with unset SHOWCONFLICTSTATE in nounset mode

["Ville Skyttä" <ville.skytta@iki.fi>]

On Mon, 1 Apr 2024 at 17:26, Junio C Hamano <gitster@pobox.com> wrote:
>
> Ville Skyttä <ville.skytta@iki.fi> writes:
>
> > I initially actually changed those very lines too when working on the
> > fix for the issue I faced with GIT_PS1_SHOWCONFLICTSTATE. However,
> > both occurrences are within __git_ps1_show_upstream, and the only call
> > site for that function is protected by a check on the variable that
> > does take possible unset state into account; the function will in the
> > file's current form never be called with it unset. Additionally, the
> > first occurrence is immediately following a line that sets the
> > variable, so that one is "doubly protected".
> >
> > Therefore, I decided to undo those changes and not include them here.
> > I guess it's a matter of taste whether one finds it desirable to
> > protect those accesses nevertheless, but it's not strictly necessary.
>
> I am glad you took a look into it already.  I wonder if we can
> somehow keep this "institutional knowledge" to help the next person
> by saving them from wasting time wondering about the reason why it
> is safe (iow, what you have found out and described above).  Perhaps
> a patch like this?  I dunno.

TBH, I'd personally just rather patch the "vulnerable" reference to
guard against this. Sent that approach in another mail with subject
"[PATCH] completion: protect prompt against unset SHOWUPSTREAM in
nounset mode".