[master] 68fcec1 Use http_Unset for a header instead of moving backwards a pointer.

[Arianna Aondio]

commit 68fcec15bb781e8679f70ed5f50d3c4363fc74de
Author: Arianna Aondio <arianna.aondio at varnish-software.com>
Date:   Fri Mar 13 15:08:11 2015 +0100

    Use http_Unset for a header instead of moving backwards a pointer.
    
    Provide test case for bug #1684.

diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index f39fb81..71770b1 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -269,8 +269,10 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
 	else
 		AZ(bo->req);
 
+	if (bo->retries > 0)
+		http_Unset(bo->bereq, "\012X-Varnish:");
+
 	http_PrintfHeader(bo->bereq, "X-Varnish: %u", VXID(bo->vsl->wid));
-	bo->bereq->nhd--;
 
 	VCL_backend_fetch_method(bo->vcl, wrk, NULL, bo, bo->bereq->ws);
 
diff --git a/bin/varnishtest/tests/r01684.vtc b/bin/varnishtest/tests/r01684.vtc
new file mode 100644
index 0000000..3e0e422
--- /dev/null
+++ b/bin/varnishtest/tests/r01684.vtc
@@ -0,0 +1,38 @@
+varnishtest  "Regression test for #1684"
+server s1 {
+        rxreq
+        txresp -hdr "foo: 1"
+        accept
+        rxreq
+        txresp -hdr "foo: 2"
+        accept
+        rxreq
+        txresp -hdr "foo: 3"
+} -start
+
+varnish v1 -vcl+backend {
+        sub vcl_recv { return (pass); }
+        sub vcl_backend_response {
+                set beresp.http.bar = bereq.retries;
+                if (beresp.http.foo != bereq.http.stop) {
+                        return (retry);
+                }
+        }
+} -start
+
+# check log for the aborted POST
+logexpect l1 -v v1 {
+	expect * =	BereqHeader "^X-Varnish:"
+	expect * =	BereqUnset	"^X-Varnish:"
+	expect * =	BereqHeader	"^X-Varnish"
+} -start
+
+varnish v1 -cliok "param.set debug +syncvsl"
+varnish v1 -cliok "param.set max_retries 2"
+
+client c1 {
+        txreq -hdr "stop: 3"
+        rxresp
+        expect resp.http.foo == 3
+} -run
+