Re: [PATCH 2/2] promptinit: Fix prompt cleanups

[Arseny Maslennikov <ar@cs.msu.ru>]

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On Mon, Feb 22, 2021 at 10:29:52AM -0800, Bart Schaefer wrote:
> On Mon, Jan 25, 2021 at 12:17 AM Arseny Maslennikov <ar@cs.msu.ru> wrote:
> >
> > The promptinit framework fails to apply cleanup commands of the current
> > theme on any theme change other than "prompt restore", as well as when
> > invoking setup functions of a certain $theme as an implementation detail
> > of `prompt -[hp] $theme'.
> 
> Thanks, I did have a chance to look at this.
> 
> > We fix it in the following way, hopefully without breaking compatibility:
> > * Rename zstyle `cleanup' on the context `:prompt-theme' to `restore'
> >   everywhere but in prompt_cleanup(). It is only used as a restore
> >   mechanism now.
> > * Ensure prompt_cleanup() continues to store its command list in the
> >   `cleanup' style.
> > * Clean up before theme switch at the end of set_prompt().
> 
> These all seem fine, conceptually.
> 
> > * Prepend every use of prompt_*_setup (which might modify the shell
> >   state in ways that require cleanup) with a cleanup run.
> 
> Have you confirmed that this is a no-op when there has not been a
> previous installation of a theme?

I double-checked right now; in that case, with the patch applied as
posted, it is a no-op when the command 'prompt -p' is invoked, but not
when 'prompt -h' is — the trap does not run. Thanks for the good catch!

The following diff on top of my patch fixes it:

--->8---

diff --git a/Functions/Prompts/promptinit b/Functions/Prompts/promptinit
index ab2b50857..5c7dcc5a1 100644
--- a/Functions/Prompts/promptinit
+++ b/Functions/Prompts/promptinit
@@ -105,9 +105,11 @@ Use prompt -h <theme> for help on specific themes.'
         local +h PS1=$PS1 PS2=$PS2 PS3=$PS3 PS4=$PS4 RPS1=$RPS1 RPS2=$RPS2
         local +h PROMPT=$PROMPT RPROMPT=$RPROMPT RPROMPT2=$RPROMPT2 PSVAR=$PSVAR
         local -a precmd_functions preexec_functions
+        local theme_reset=''
       else
-        trap 'zstyle -t :prompt-theme cleanup; prompt_${prompt_theme[1]}_setup "${(@)prompt_theme[2,-1]}"' 0
+        local theme_reset='prompt_${prompt_theme[1]}_setup "${(@)prompt_theme[2,-1]}"'
       fi
+      trap 'zstyle -t :prompt-theme cleanup;'"${theme_reset:+ $theme_reset}" 0
       ;;
   esac
   case "$opt" in

--------

> 
> > * Adjust `prompt restore' to do both parts of the newly split restore
> >   mechanism, cleanup first.
> 
> Also fine.  Just a couple of nit-picky things about the diff itself:
> 
> > diff --git a/Functions/Prompts/promptinit b/Functions/Prompts/promptinit
> > index 5e42ebdd3..1c6d27ad7 100644
> > --- a/Functions/Prompts/promptinit
> > +++ b/Functions/Prompts/promptinit
> > @@ -123,6 +125,7 @@ Use prompt -h <theme> for help on specific themes.'
> >             # The next line is a bit ugly.  It (perhaps unnecessarily)
> >             # runs the prompt theme setup function to ensure that if
> >             # the theme has a _help function that it's been autoloaded.
> > +           zstyle -t :prompt-theme cleanup
> >             prompt_$2_setup
> >           fi
> >           if functions prompt_$2_help >/dev/null; then
> 
> Placement of the added zstyle call makes the comment incorrect, move
> it above the comment?

Will do.

> 
> > @@ -179,28 +182,41 @@ Use prompt -h <theme> for help on specific themes.'
> > +  # Will add the hook this time.
> > +  prompt_cleanup "$@"
> 
> This is logically correct, but I don't think it adds much in terms of
> maintainability to make this a recursive call; there are only 2
> commands executed in that event.

Ok; I'll have to refactor this again. :)

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