Re: _expand_alias does not expand aliases that contain an "!"

[Bart Schaefer <schaefer@brasslantern.com>]

On Aug 31,  1:50pm, Bart Schaefer wrote:
} Subject: Re: _expand_alias does not expand aliases that contain an "!"
}
} On Aug 30,  7:58pm, Jonathan H wrote:
} }
} } Oddly enough, for me _expand_alias works for all characters in
} } [*#?@:+-^%$.,]. the only character that didn't work and wasn't already
} } meaningful to the shell was the exclamation point.
} 
} Hmm.  Indeed, something is treating "!" as additionally special.  The
} interesting part is that it does not always treat the first character of
} the $HISTCHARS variable as special, nor does it treat ! as special when
} it is not the first character of $HISTCHARS.
} 
} Or (more likely) internally somewhere is explicitly un-quoting file
} expansion characters but is not doing so for history characters.  This
} could probably be fixed but might take a while to trace down.

What this boils down to is that get_comp_string() calls the lexer to
parse the word to be completed.  Metacharacters like '*' and '?' get
tokenized by the lexer, but the history character does not.

Eventually callcompfunc() invokes multiquote() on the lexed word, which
calls quotestring(), which does not re-quote the tokenized characters
but does quote the history characters.  (compcore.c:706)

callcompfunc() then calls untokenize() and we end up with backslashes
in front of history characters but not in front of pattern characters.

I think that means the fix is as easy as the patch below; this doesn't
seem to break history expansion, and I can't think of any other reason
we'd want history enabled when performing word completion.

The first hunk of the patch backs out the hack in 33069.

There's a remaining, probably autoloading-related, weirdness, which is
that _expand_alias doesn't work the first time you try it unless the
completion system has already been invoked some other way (including
by having tried _expand_alias at least once already).  Tracing with 
_complete_debug shows that the first time through, a backslash is
being inserted before '!' even though NO_banghist is in effect; but
on the second and later attempts, there's no backslash.  Puzzling.


diff --git a/Completion/Base/Completer/_expand_alias b/Completion/Base/Completer/_expand_alias
index 9064ce8..8240e41 100644
--- a/Completion/Base/Completer/_expand_alias
+++ b/Completion/Base/Completer/_expand_alias
@@ -25,8 +25,6 @@ else
   pre=(_main_complete - aliases)
 fi
 
-[[ "$compstate[quoting]" = (single|double) ]] || word="${(Q)word}"
-
 zstyle -s ":completion:${curcontext}:" regular tmp || tmp=yes
 case $tmp in
 always) sel=r;;
diff --git a/Completion/compinit b/Completion/compinit
index f9d2c57..dc84637 100644
--- a/Completion/compinit
+++ b/Completion/compinit
@@ -138,6 +138,7 @@ _comp_options=(
        unset
     NO_allexport
     NO_aliases
+    NO_banghist
     NO_cshnullglob
     NO_cshjunkiequotes
     NO_errexit