Bug 531886 - [regression] *.mfasl fastload caches not invalidated after build / changing XUL/JS code. r=bsmedberg

config/rules.mk

@@ -2291,3 +2291,6 @@ CHECK_FROZEN_VARIABLES = $(foreach var,$(FREEZE_VARIABLES), \
 
 libs export libs::
 	$(CHECK_FROZEN_VARIABLES)
+
+default::
+	if test -d $(DIST)/bin ; then touch $(DIST)/bin/.purgecaches ; fi

js/src/config/rules.mk

@@ -2291,3 +2291,6 @@ CHECK_FROZEN_VARIABLES = $(foreach var,$(FREEZE_VARIABLES), \
 
 libs export libs::
 	$(CHECK_FROZEN_VARIABLES)
+
+default::
+	if test -d $(DIST)/bin ; then touch $(DIST)/bin/.purgecaches ; fi

toolkit/xre/nsAppRunner.cpp

@@ -248,6 +248,7 @@ extern void InstallSignalHandlers(const char *ProgramName);
 #include "nsX11ErrorHandler.h"
 
 #define FILE_COMPATIBILITY_INFO NS_LITERAL_CSTRING("compatibility.ini")
+#define FILE_INVALIDATE_CACHES NS_LITERAL_CSTRING(".purgecaches")
 
 int    gArgc;
 char **gArgv;
@@ -2309,9 +2310,10 @@ SelectProfile(nsIProfileLock* *aResult, nsINativeAppSupport* aNative,
 static PRBool
 CheckCompatibility(nsIFile* aProfileDir, const nsCString& aVersion,
                    const nsCString& aOSABI, nsIFile* aXULRunnerDir,
-                   nsIFile* aAppDir, PRBool* aCachesOK)
+                   nsIFile* aAppDir, nsILocalFile* aFlagFile, 
+                   PRBool* aCachesOK)
 {
-  *aCachesOK = false;
+  *aCachesOK = PR_FALSE;
   nsCOMPtr<nsIFile> file;
   aProfileDir->Clone(getter_AddRefs(file));
   if (!file)
@@ -2363,10 +2365,18 @@ CheckCompatibility(nsIFile* aProfileDir, const nsCString& aVersion,
       return PR_FALSE;
   }
 
-  rv = parser.GetString("Compatibility", "InvalidateCaches", buf);
-  
   // If we see this flag, caches are invalid.
+  rv = parser.GetString("Compatibility", "InvalidateCaches", buf);
   *aCachesOK = (NS_FAILED(rv) || !buf.EqualsLiteral("1"));
+  
+#ifdef DEBUG
+  PRBool purgeCaches = PR_FALSE;
+  if (aFlagFile) {
+    aFlagFile->Exists(&purgeCaches);
+  }
+
+  *aCachesOK = !purgeCaches && *aCachesOK;
+#endif
   return PR_TRUE;
 }
 
@@ -3267,11 +3277,34 @@ XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
     // by the BuildVersion function.
     // Also check to see if something has happened to invalidate our
     // fastload caches, like an extension upgrade or installation.
+ 
+     // If we see .purgecaches, that means someone did a make. 
+     // Re-register components to catch potential changes.
+     // We only offer this in debug builds, though.
+     nsCOMPtr<nsILocalFile> flagFile;
+#ifdef DEBUG
+     rv = NS_ERROR_FILE_NOT_FOUND;
+     nsCOMPtr<nsIFile> fFlagFile;
+     if (gAppData->directory) {
+       rv = gAppData->directory->Clone(getter_AddRefs(fFlagFile));
+     }
+     flagFile = do_QueryInterface(fFlagFile);
+     if (flagFile) {
+       flagFile->SetNativeLeafName(FILE_INVALIDATE_CACHES);
+     }
+ #endif
     PRBool cachesOK;
     PRBool versionOK = CheckCompatibility(profD, version, osABI, 
                                           dirProvider.GetGREDir(),
-                                          gAppData->directory, &cachesOK);
-
+                                          gAppData->directory, flagFile,
+                                          &cachesOK);
+     if (CheckArg("purgecaches")) {
+       cachesOK = PR_FALSE;
+     }
+     if (PR_GetEnv("MOZ_PURGE_CACHES")) {
+       cachesOK = PR_FALSE;
+     }
+ 
     // Every time a profile is loaded by a build with a different version,
     // it updates the compatibility.ini file saying what version last wrote
     // the fastload caches.  On subsequent launches if the version matches, 
@@ -3313,6 +3346,11 @@ XRE_main(int argc, char* argv[], const nsXREAppData* aAppData)
                    dirProvider.GetGREDir(), gAppData->directory);
     }
 
+#ifdef DEBUG
+    if (flagFile) {
+      flagFile->Remove(PR_TRUE);
+    }
+#endif
     PRBool needsRestart = PR_FALSE;
     PRBool appInitiatedRestart = PR_FALSE;