Bug 1737198 - Part 6: Enable strict fallback mode by default in Nightly. r=necko-reviewers,valentin

Differential Revision: https://phabricator.services.mozilla.com/D132112

modules/libpref/init/StaticPrefList.yaml

@@ -9833,7 +9833,7 @@
 # If true, don't fallback to native DNS upon network errors.
 - name: network.trr.strict_native_fallback
   type: RelaxedAtomicBool
-  value: false
+  value: @IS_NIGHTLY_BUILD@
   mirror: always
 
 # Single TRR request timeout, in milliseconds

netwerk/test/unit/head_trr.js

@@ -57,6 +57,9 @@ function trr_test_setup() {
   );
   addCertFromFile(certdb, "http2-ca.pem", "CTu,u,u");
 
+  // Turn off strict fallback mode for most tests, it is tested specifically.
+  Services.prefs.setBoolPref("network.trr.strict_native_fallback", false);
+
   // We intentionally don't set the TRR mode. Each test should set it
   // after setup in the first test.
 
@@ -91,6 +94,7 @@ function trr_clear_prefs() {
   Services.prefs.clearUserPref(
     "network.trr.send_empty_accept-encoding_headers"
   );
+  Services.prefs.clearUserPref("network.trr.strict_native_fallback");
 }
 
 /// This class sends a DNS query and can be awaited as a promise to get the

netwerk/test/unit/trr_common.js

@@ -348,7 +348,7 @@ async function test_strict_native_fallback() {
   setModeAndURI(2, "doh?responseIP=2.2.2.2&corruptedAnswer=true");
   await new TRRDNSListener("bar.example.com", "127.0.0.1"); // Should fallback
 
-  Services.prefs.clearUserPref("network.trr.strict_native_fallback");
+  Services.prefs.setBoolPref("network.trr.strict_native_fallback", false);
   Services.prefs.clearUserPref("network.trr.request_timeout_ms");
   Services.prefs.clearUserPref("network.trr.request_timeout_mode_trronly_ms");
 }