[fix] compiler errors should be parsed properly and handle bytestream…

… provider uri | #BAZEL-763 Done

Merge-request: BAZEL-MR-668
Merged-by: Marcin Abramowicz <marcin.abramowicz@jetbrains.com>

server/src/main/kotlin/org/jetbrains/bsp/bazel/server/bep/BepServer.java

@@ -12,11 +12,13 @@
 import com.google.devtools.build.v1.PublishBuildToolEventStreamRequest;
 import com.google.devtools.build.v1.PublishBuildToolEventStreamResponse;
 import com.google.devtools.build.v1.PublishLifecycleEventRequest;
+import com.google.protobuf.ByteString;
 import com.google.protobuf.Empty;
 import io.grpc.stub.StreamObserver;
 import java.io.IOException;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystemNotFoundException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -177,11 +179,22 @@ private void consumeActionCompletedEvent(BuildEventStreamProtos.BuildEvent event
     }
   }
 
-  @SuppressWarnings("LiteByteStringUtf8")
   private void consumeUnsuccessfulActionCompletedEvent(
       BuildEventStreamProtos.ActionExecuted actionEvent, String label) {
-    String stdErrText = actionEvent.getStderr().toByteString().toStringUtf8();
-    processDiagnosticText(stdErrText, label);
+    if (actionEvent.getStderr().getFileCase() == BuildEventStreamProtos.File.FileCase.URI) {
+      try {
+        var path = Paths.get(URI.create(actionEvent.getStderr().getUri()));
+        String stdErrText = Files.readString(path);
+        processDiagnosticText(stdErrText, label);
+      } catch (FileSystemNotFoundException | IOException e) {
+        LOGGER.warn(e);
+      }
+    } else if (actionEvent.getStderr().getFileCase()
+            == BuildEventStreamProtos.File.FileCase.CONTENTS) {
+      processDiagnosticText(actionEvent.getStderr().getContents().toStringUtf8(), label);
+    } else {
+      processDiagnosticText("", label);
+    }
   }
 
   private void processDiagnosticText(String stdErrText, String targetLabel) {