(nstr_string_ok): New.

(nstr_comp): Use it to fix oops on `des='.  Reported by Doug Wescott.

diff --git a/src/lib/subs/nstr.c b/src/lib/subs/nstr.c
index 9015d0186f0f8e49edd8546f7b7272201e1051de..c5dc880acc80ef0005f3d0c327b89a9ffbbb2bd1 100644 (file)
--- a/src/lib/subs/nstr.c
+++ b/src/lib/subs/nstr.c
@@ -127,12 +127,10 @@ nstr_comp(struct nscstr *np, int len, int type, char *str)
             * must name selectors.
             */
            if (!nstr_resolve_id(&np->lft, ca, lft_caidx,
-                                nstr_promote(ca[rgt_caidx].ca_type)
-                                == NSC_STRING))
+                                nstr_string_ok(ca, rgt_caidx)))
                return -1;
            if (!nstr_resolve_id(&np->rgt, ca, rgt_caidx,
-                                nstr_promote(ca[lft_caidx].ca_type)
-                                == NSC_STRING))
+                                nstr_string_ok(ca, lft_caidx)))
                return -1;
        }
 
@@ -336,9 +334,9 @@ nstr_match_ca(struct valstr *val, struct castr *ca)
 /*
  * Match VAL in a selector's values, return its (non-negative) value.
  * TYPE is the context type, a file type.
- * CA is ef_cadef(TYPE).
- * Match values of selector descriptor CA[IDX], provided CA is not
- * null and IDX is not negative.
+ * CA is ef_cadef(TYPE).  If it is null, then IDX must be negative.
+ * Match values of selector descriptor CA[IDX], provided IDX is not
+ * negative.
  * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
  * several.
  * TODO: This is just a stub and works only for NSC_TYPEID.
@@ -362,6 +360,16 @@ nstr_match_val(struct valstr *val, int type, struct castr *ca, int idx)
     return typematch(id, type);
 }
 
+/*
+ * Can CA[IDX] be compared to a string?
+ * Return 0 for negative IDX.
+ */
+int
+nstr_string_ok(struct castr *ca, int idx)
+{
+    return idx >= 0 && nstr_promote(ca[idx].ca_type) == NSC_STRING;
+}
+
 /*
  * Change VAL to resolve identifier to selector or string.
  * Return VAL on success, NULL on error.