Fix data race in IndexRegistry#getBazelRegistryJson

fmeum · copybara-github · commit 693615038fcb · 2024-06-05T10:38:35.000-07:00
Should fix the following crash observed in the wild: ``` FATAL: bazel crashed due to an internal error. Printing stack trace: java.lang.RuntimeException: Unrecoverable error while evaluating node 'RepoSpecKey{moduleKey=rules_pkg@0.7.0, registryUrl=https://bcr.bazel.build/}' (requested by nodes 'com.google.devtools.build.lib.bazel.bzlmod.BazelModuleResolutionValue$$Lambda/0x00000008005fd220@38aba3ca') at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:550) at com.google.devtools.build.lib.concurrent.AbstractQueueVisitor$WrappedRunnable.run(AbstractQueueVisitor.java:414) at java.base/java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(Unknown Source) at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source) at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source) at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source) at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) Caused by: java.lang.NullPointerException: Cannot invoke "com.google.devtools.build.lib.events.StoredEventHandler.replayOn(com.google.devtools.build.lib.events.ExtendedEventHandler)" because "this.bazelRegistryJsonEvents" is null at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.getBazelRegistryJson(IndexRegistry.java:336) at com.google.devtools.build.lib.bazel.bzlmod.IndexRegistry.getRepoSpec(IndexRegistry.java:295) at com.google.devtools.build.lib.bazel.bzlmod.RepoSpecFunction.compute(RepoSpecFunction.java:52) at com.google.devtools.build.skyframe.AbstractParallelEvaluator$Evaluate.run(AbstractParallelEvaluator.java:461) ... 7 more ``` Closes #22639. PiperOrigin-RevId: 640572972 Change-Id: Id24ce3476df55fa75d6f3291e100b1037f0793f4
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/IndexRegistry.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/IndexRegistry.java
@@ -321,9 +321,10 @@ private String getSourceJsonUrl(ModuleKey key) {
 
   private Optional<BazelRegistryJson> getBazelRegistryJson(ExtendedEventHandler eventHandler)
       throws IOException, InterruptedException {
-    if (bazelRegistryJson == null) {
+    if (bazelRegistryJson == null || bazelRegistryJsonEvents == null) {
       synchronized (this) {
-        if (bazelRegistryJson == null) {
+        if (bazelRegistryJson == null || bazelRegistryJsonEvents == null) {
+          Preconditions.checkState(bazelRegistryJson == null && bazelRegistryJsonEvents == null);
           var storedEventHandler = new StoredEventHandler();
           bazelRegistryJson =
               grabJson(
