Bug 1743122 - Disable TRR temp blocklist feature in tests. r=valentin,necko-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D132245

modules/libpref/init/StaticPrefList.yaml

@@ -9856,6 +9856,15 @@
   value: @IS_NIGHTLY_BUILD@
   mirror: always
 
+# If false, the temporary blocklisting feature is disabled.
+# This is useful for tests to prevent bleeding extra reqs
+# between tasks, since we may attempt to look up the
+# parent domain in the background when blocklisting a host.
+- name: network.trr.temp_blocklist
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
 # Single TRR request timeout, in milliseconds
 - name: network.trr.request_timeout_ms
   type: RelaxedAtomicUint32

netwerk/dns/TRRService.cpp

@@ -889,6 +889,11 @@ bool TRRService::IsTemporarilyBlocked(const nsACString& aHost,
                                       bool aPrivateBrowsing,
                                       bool aParentsToo)  // false if domain
 {
+  if (!StaticPrefs::network_trr_temp_blocklist()) {
+    LOG(("TRRService::IsTemporarilyBlocked temp blocklist disabled by pref"));
+    return false;
+  }
+
   if (mMode == nsIDNSService::MODE_TRRONLY) {
     return false;  // might as well try
   }
@@ -970,6 +975,11 @@ bool TRRService::IsExcludedFromTRR_unlocked(const nsACString& aHost) {
 void TRRService::AddToBlocklist(const nsACString& aHost,
                                 const nsACString& aOriginSuffix,
                                 bool privateBrowsing, bool aParentsToo) {
+  if (!StaticPrefs::network_trr_temp_blocklist()) {
+    LOG(("TRRService::AddToBlocklist temp blocklist disabled by pref"));
+    return;
+  }
+
   LOG(("TRR blocklist %s\n", nsCString(aHost).get()));
   nsAutoCString hashkey(aHost + aOriginSuffix);
 

netwerk/test/unit/head_trr.js

@@ -60,6 +60,11 @@ function trr_test_setup() {
   // Turn off strict fallback mode for most tests, it is tested specifically.
   Services.prefs.setBoolPref("network.trr.strict_native_fallback", false);
 
+  // Turn off temp blocklist feature in tests. When enabled we may issue a
+  // lookup to resolve a parent name when blocklisting, which may bleed into
+  // and interfere with subsequent tasks.
+  Services.prefs.setBoolPref("network.trr.temp_blocklist", false);
+
   // We intentionally don't set the TRR mode. Each test should set it
   // after setup in the first test.
 
@@ -95,6 +100,7 @@ function trr_clear_prefs() {
     "network.trr.send_empty_accept-encoding_headers"
   );
   Services.prefs.clearUserPref("network.trr.strict_native_fallback");
+  Services.prefs.clearUserPref("network.trr.temp_blocklist");
 }
 
 /// This class sends a DNS query and can be awaited as a promise to get the