bug#30280: async-shell-command-display-buffer doesn't work anymore

[Juri Linkov]

> I attach a patch which addresses both bugs.  Its solution for (a) is to
> make the advice disposable, i.e. it removes itself from the process
> filter after it has fulfilled its purpose of displaying the output
> buffer.  A syntactically simpler implementation of this could use a
> plain boolean switch instead of removing the advice, but IMO the latter
> is semantically more sound (and possibly more performant in subsequent
> invocations of the process filter, though this should be irrelevant).
>
> WDYT?

Thanks, I confirm this is the right thing to do and your patch fixes
the reported issue.

> P.S. Would patch(es) for aesthetic changes to the rest of shell-command
> (such as removing redundant variables, inverting the condition of the
> massive if-then-else to reduce indentation, etc.) be welcome?  If so,
> where should I send them?

Such changes are always welcome as patches separate from the actual fixes,
i.e. when not amalgamating bug fixes and code beautification/refactoring
in the same patch.