Bug 284188 - Forcefully prevent infinite-restart bugs by setting an environment var. r=darin

toolkit/xre/nsAppRunner.cpp

@@ -1725,7 +1725,6 @@ int xre_main(int argc, char* argv[], const nsXREAppData* aAppData)
   // Allows the user to forcefully bypass the restart process at their
   // own risk. Useful for debugging or for tinderboxes where child 
   // processes can be problematic.
-  PRBool noRestart = PR_FALSE;
   {
     // Start the real application
     ScopedXPCOMStartup xpcom;
@@ -1808,29 +1807,34 @@ int xre_main(int argc, char* argv[], const nsXREAppData* aAppData)
           return 0;
         }
 
-        char* noEMRestart = PR_GetEnv("NO_EM_RESTART");
-        noRestart = noEMRestart && !strcmp("1", noEMRestart);
-        if (!noRestart && upgraded) {
+        if (upgraded) {
           rv = em->CheckForMismatches(&needsRestart);
-          NS_ASSERTION(NS_SUCCEEDED(rv), "Oops, looks like you have a extensions.rdf file generated by a buggy nightly build. Please remove it!");
           if (NS_FAILED(rv)) {
             needsRestart = PR_FALSE;
             upgraded = PR_FALSE;
           }
         }
 
-        if (noRestart || (!upgraded || !needsRestart))
+        if (!upgraded || !needsRestart)
           em->Start(cmdLine, componentsListChanged, &needsRestart);
       }
 
-      if (noRestart || (!upgraded && !needsRestart)) {
+      char* noEMRestart = PR_GetEnv("NO_EM_RESTART");
+      if (noEMRestart && *noEMRestart) {
+        if (upgraded || needsRestart) {
+          NS_WARNING("EM tried to force us to restart twice! Forcefully preventing that.");
+        }
+        needsRestart = upgraded = PR_FALSE;
+      }
+
+      if (!upgraded && !needsRestart) {
 
         // clear out any environment variables which may have been set 
         // during the relaunch process now that we know we won't be relaunching.
         PR_SetEnv("XRE_PROFILE_PATH=");
         PR_SetEnv("XRE_START_OFFLINE=");
         PR_SetEnv("XRE_IMPORT_PROFILES=");
-        
+        PR_SetEnv("NO_EM_RESTART=");
 
 #ifdef XP_MACOSX
         // we re-initialize the command-line service and do appleevents munging
@@ -1914,7 +1918,10 @@ int xre_main(int argc, char* argv[], const nsXREAppData* aAppData)
   }
 
   // Restart the app after XPCOM has been shut down cleanly. 
-  if (!noRestart && needsRestart) {
+  if (needsRestart) {
+    // After this restart, we don't want to restart any more!
+    PR_SetEnv("NO_EM_RESTART=1");
+
     nsCAutoString path;
     lf->GetNativePath(path);