[PATCH] completion: don't treat '--' as an option called '-' with _arguments -s

[m0viefreak <m0viefreak.cm@xxxxxxxxxxxxxx>]

Assume the following:

  _foo() { _arguments -s '-a[opt]' '--[end of options]' }

Before this change:

  $ foo --<tab>

would complete to

  $ foo --a

which makes no sense. As a real-world example compare

  $ git diff --ca<tab>

It wrongly offers all the single letter options.

The reason is that the '--' is interpreted as a single letter
option called '-'. Then, with -s given, '-a' and '--' may be
combined to '-a-' or '--a'.

Instead, treat '--' specially and never consider it a single
letter option. This behavior then corresponds to the common
practice of 'end of options' and should be safe, since there
probably isn't any program in existence that actually
uses '--' as a single letter option called '-'.
---
 Src/Zle/computil.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/Src/Zle/computil.c b/Src/Zle/computil.c
index f5e6ba1..b11c39f 100644
--- a/Src/Zle/computil.c
+++ b/Src/Zle/computil.c
@@ -1500,9 +1500,11 @@ parse_cadef(char *nam, char **args)
 		nodopts++;
 
 	    /* If this is for single-letter option we also store a
-	     * pointer for the definition in the array for fast lookup. */
+	     * pointer for the definition in the array for fast lookup.
+	     * But don't treat '--' as a single option called '-' */
 
-	    if (single && name[1] && !name[2])
+
+	    if (single && name[1] && !name[2] && name[1] != '-')
 		ret->single[STOUC(name[1])] = opt;
 
 	    if (again == 1) {
@@ -2034,7 +2036,9 @@ ca_parse_line(Cadef d, int multi, int first)
 	    state.optbeg = state.argbeg = state.inopt = cur;
 	    state.argend = argend;
 	    state.singles = (d->single && (!pe || !*pe) &&
-			     state.curopt->name[1] && !state.curopt->name[2]);
+			     state.curopt->name[1] && !state.curopt->name[2] &&
+			     /* Don't treat '--' as a single option called '-' */
+			     state.curopt->name[1] != '-');
 
 	    if (!state.oargs[state.curopt->num])
 		state.oargs[state.curopt->num] = znewlinklist();
-- 
1.9.1.286.g5172cb3