More tests for failed backrefs

src/tests/backref_basic.vtc

@@ -72,11 +72,18 @@ varnish v1 -vcl {
 
 	sub vcl_synth {
 		# Call to backref() before match()
-		set resp.http.nomatch = barbaz.backref(0, "fallback");
+		# Also tests the default fallback.
+		set resp.http.nomatch = barbaz.backref(0);
 
 		# match() and backref() now re-use the object's task scope
 		if (barbaz.match("barbaz")) {
 			set resp.http.bar0 = barbaz.backref(0, "error0");
+
+			# backref out of range
+			set resp.http.bar3 = barbaz.backref(3, "error3");
+			set resp.http.bar-1 = barbaz.backref(-1, "error-1");
+			set resp.http.barinf
+			    = barbaz.backref(4294967296, "errorinf");
 		}
 
 		# match fails
@@ -107,8 +114,10 @@ client c1 -repeat 2 {
 	txreq
 	rxresp
 	expect resp.status == "200"
-	expect resp.http.nomatch == "fallback"
+	expect resp.http.nomatch == "**BACKREF METHOD FAILED**"
 	expect resp.http.bar0 == "barbaz"
+	expect resp.http.bar3 == "error3"
+	expect resp.http.barinf == "errorinf"
 	expect resp.http.frob1 == "false"
 	expect resp.http.frob1-0 == "error0"
 	expect resp.http.frob1-1 == "error1"
@@ -128,6 +137,9 @@ client c1 -repeat 2 {
 logexpect l1 -v v1 -d 1 -g vxid -q "VCL_Error" {
 	expect 0 * Begin req
 	expect * = VCL_Error "^vmod pcre2 error: barbaz.backref.0. called without prior match$"
+	expect * = VCL_Error "^vmod pcre2 error: in barbaz.backref.3.: unknown substring$"
+	expect * = VCL_Error "^vmod pcre2 error: ref .-1. out of range in barbaz.backref.. .must be >= 0 and <= 4294967295.$"
+	expect * = VCL_Error "^vmod pcre2 error: ref .4294967296. out of range in barbaz.backref.. .must be >= 0 and <= 4294967295.$"
 	expect * = VCL_Error "^vmod pcre2 error: in frobnitz.backref.0.: no match$"
 	expect * = VCL_Error "^vmod pcre2 error: in frobnitz.backref.1.: no match$"
 	expect * = VCL_Error "^vmod pcre2 error: in frobnitz.backref.2.: no match$"