[master] 9d81a71 Error out on comparisons of different types, where stringification wouldn't make sense.

[Poul-Henning Kamp]

commit 9d81a71a1987f07021ae9f653b0f8f4c54544dbe
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Thu Dec 8 20:46:10 2016 +0000

    Error out on comparisons of different types, where stringification
    wouldn't make sense.
    
    Fixes: #2099
    
    NB: This _may_ expose certain corner cases of unwise symbol overloading
        in VCL.

diff --git a/bin/varnishtest/tests/v00020.vtc b/bin/varnishtest/tests/v00020.vtc
index 513f56c..cb8ea6e 100644
--- a/bin/varnishtest/tests/v00020.vtc
+++ b/bin/varnishtest/tests/v00020.vtc
@@ -308,3 +308,14 @@ varnish v1 -errvcl {Symbol not found: 'storage.foo' (expected type STEVEDORE):}
 		set beresp.storage = storage.foo;
 	}
 }
+
+varnish v1 -errvcl {Comparison of different types: BACKEND '==' STRING} {
+	backend b1 { .host = "127.0.0.1"; }
+
+	sub vcl_backend_response {
+		set beresp.http.bereq_backend = bereq.backend;
+		if (bereq.backend == beresp.http.bereq_backend) {
+			set beresp.http.bereq_backend_cmp = "ok";
+		}
+	}
+}
diff --git a/lib/libvcc/vcc_expr.c b/lib/libvcc/vcc_expr.c
index 0aca3da..9581cbf 100644
--- a/lib/libvcc/vcc_expr.c
+++ b/lib/libvcc/vcc_expr.c
@@ -1184,6 +1184,14 @@ vcc_expr_cmp(struct vcc *tl, struct expr **e, vcc_type_t fmt)
 		e2 = NULL;
 		vcc_expr0(tl, &e2, (*e)->fmt);
 		ERRCHK(tl);
+		if (e2->fmt != (*e)->fmt) {
+			VSB_printf(tl->sb, "Comparison of different types: ");
+			VSB_printf(tl->sb, "%s ", (*e)->fmt->name);
+			vcc_ErrToken(tl, tk);
+			VSB_printf(tl->sb, " %s\n", e2->fmt->name);
+			vcc_ErrWhere(tl, tk);
+			return;
+		}
 		*e = vcc_expr_edit(BOOL, buf, *e, e2);
 		return;
 	}
diff --git a/lib/libvcc/vcc_symb.c b/lib/libvcc/vcc_symb.c
index 14831b8..21dd348 100644
--- a/lib/libvcc/vcc_symb.c
+++ b/lib/libvcc/vcc_symb.c
@@ -128,7 +128,7 @@ VCC_Symbol(struct vcc *tl, struct symbol *parent,
 		if (q < e)
 			break;
 		if (kind != SYM_NONE && sym->kind != kind)
-			continue;
+			break;
 		if (kind == SYM_NONE && sym->kind == kind)
 			continue;
 		break;