Catch case where pattern match reports success but with an empty string. This probably

corresponds to ill-specified pattern such as '&'

diff --git a/lib/expr/exeval.c b/lib/expr/exeval.c
index 29dfaeba0ddb462d60dedfd95dddab2d70b4078d..5301e58d55ba588227297f5187c174bc1bf74b76 100644 (file)
--- a/lib/expr/exeval.c
+++ b/lib/expr/exeval.c
@@ -828,6 +828,11 @@ exsub(Expr_t * ex, register Exnode_t * expr, void *env, int global)
                v.string = vmstrdup(ex->ve, str);
                return v;
        }
+    if (sub[0] == sub[1]) {
+               exwarn("pattern match of empty string - ill-specified pattern \"%s\"?", pat);
+               v.string = vmstrdup(ex->ve, str);
+               return v;
+    } 
        sfwrite(ex->tmp, str, sub[0]);
        if (repl)
                replace(ex->tmp, str, repl, ng, sub);