Bug 1170795 - Ignore redirect errors for synthesized cache entries. r=mayhemer

dom/workers/test/serviceworkers/fetch/fetch_tests.js

@@ -39,6 +39,12 @@ fetchXHR('synthesized-404.txt', function(xhr) {
   finish();
 });
 
+fetchXHR('synthesized-308.txt', function(xhr) {
+  my_ok(xhr.status == 308, "load should return 308");
+  my_ok(xhr.responseText == "synthesized response body", "308 load should have synthesized response");
+  finish();
+});
+
 fetchXHR('synthesized-headers.txt', function(xhr) {
   my_ok(xhr.status == 200, "load should be successful");
   my_ok(xhr.getResponseHeader("X-Custom-Greeting") === "Hello", "custom header should be set");

dom/workers/test/serviceworkers/fetch_event_worker.js

@@ -13,6 +13,12 @@ onfetch = function(ev) {
     ));
   }
 
+  else if (ev.request.url.includes("synthesized-308.txt")) {
+    ev.respondWith(Promise.resolve(
+      new Response("synthesized response body", { status: 308 })
+    ));
+  }
+
   else if (ev.request.url.includes("synthesized-headers.txt")) {
     ev.respondWith(Promise.resolve(
       new Response("synthesized response body", {

netwerk/protocol/http/nsHttpChannel.cpp

@@ -2951,8 +2951,11 @@ nsHttpChannel::OnCacheEntryCheck(nsICacheEntry* entry, nsIApplicationCache* appC
 
     // Do not return 304 responses from the cache, and also do not return
     // any other non-redirect 3xx responses from the cache (see bug 759043).
+    // However, if this is a synthesized cache entry we don't care what the
+    // content is and will return it regardless.
     NS_ENSURE_TRUE((mCachedResponseHead->Status() / 100 != 3) ||
-                   isCachedRedirect, NS_ERROR_ABORT);
+                   isCachedRedirect ||
+                   mInterceptCache == INTERCEPTED, NS_ERROR_ABORT);
 
     // Don't bother to validate items that are read-only,
     // unless they are read-only because of INHIBIT_CACHING or because