PATCH: get-line shouldn't set histline

PATCH: get-line shouldn't set histline

[Oliver Kiddle]

Using narrow-to-region modified to use undo to take advantage of the
undo limits, I'm finding issues related to the way undo handles separate
history lines. The following is one such case. The get-line widget is
meant to insert the line from the buffer stack into the current line.
Changing histline without setting the line to correspond to the text
stored for the history entry results in undo information that doesn't
make sense.

To put this into context, I've also included the function I have bound
to Ctrl-R below. Note the use of get-line towards the end. I don't
really use get-line directly anymore as narrow-to-region tends to be an
easier way to collect past history lines together in a new line. Can
anyone see how the change might cause a problem for normal get-line
usage?

Oliver

  local left right
  if [[ -n $PREDISPLAY || -z $BUFFER ]]; then
    zle .$WIDGET
  else
    zle .vi-add-next
    while true; do
      (( MARK )) || MARK=CURSOR
      if ((MARK < CURSOR)); then
	left="$LBUFFER[0,MARK-CURSOR-1]"
	right="$RBUFFER"
      else
	left="$LBUFFER"
	right="$BUFFER[MARK+1,-1]"
      fi
      narrow-to-region -p "$left"$'\u25b8' -P $'\u25c0'"$right"
      if [[ $WIDGET = accept-line-and-down-history ]]; then
	LBUFFER+=$'\n'"${(M)${LBUFFER##[^$'\n']#?}##[[:blank:]]#}"
	(( MARK = CURSOR ))
	zle split-undo
	zle get-line
      else
	MARK=-1
	break
      fi
    done
  fi


diff --git a/Src/Zle/zle_hist.c b/Src/Zle/zle_hist.c
index ffb7ce9..c61b4ef 100644
--- a/Src/Zle/zle_hist.c
+++ b/Src/Zle/zle_hist.c
@@ -894,10 +894,8 @@ zgetline(UNUSED(char **args))
 	free(s);
 	free(lineadd);
 	clearlist = 1;
-	if (stackhist != -1) {
-	    histline = stackhist;
-	    stackhist = -1;
-	}
+	/* not restoring stackhist as we're inserting into current line */
+	stackhist = -1;
     }
     return 0;
 }

Re: PATCH: get-line shouldn't set histline

[Peter Stephenson]

On Wed, 12 Aug 2015 16:26:47 +0200
Oliver Kiddle <okiddle@yahoo.co.uk> wrote:
> The get-line widget is
> meant to insert the line from the buffer stack into the current line.
> Changing histline without setting the line to correspond to the text
> stored for the history entry results in undo information that doesn't
> make sense.

Yes, I think this is just because the code was copied from the case
where the line is being set when the line editor starts.  In that case
popping the line gives you the history context around where you pushed
it.  get-line seems like it should just grab the string and keep the
current context.  But most of the times I use get-line it doesn't
actually matter, so I can't swear this is always right.

pws

Re: PATCH: get-line shouldn't set histline

[Bart Schaefer]

On Aug 12,  4:26pm, Oliver Kiddle wrote:
}
} The get-line widget is meant to insert the line from the buffer stack
} into the current line. Changing histline without setting the line to
} correspond to the text stored for the history entry results in undo
} information that doesn't make sense.
}
} Can anyone see how the change might cause a problem for normal
} get-line usage?

I can't think of a way this would cause a problem, but I hardly ever
use get-line.