fix: Reduce freeze in ProjectUpdater

base/src/META-INF/blaze-base.xml

@@ -424,6 +424,9 @@
     <registryKey defaultValue="true"
                  description="Enable basic syntax highliting in Query Sync's 'Analysis Disabled' mode"
                  key="bazel.qsync.enable.basic.highlighting.in.non.analysis.mode"/>
+    <registryKey defaultValue="true"
+                 description="Use coroutine-based ProjectUpdater implementation. It it is supposed to reduce the freeze that happens during sync"
+                 key="bazel.qsync.enable.coroutine.project.updater"/>
     <editorNotificationProvider implementation="com.google.idea.blaze.base.wizard2.BazelNotificationProvider"/>
   </extensions>
 

base/src/com/google/idea/blaze/base/qsync/ProjectUpdater.java

@@ -37,7 +37,6 @@
 import com.google.idea.blaze.qsync.project.ProjectPath;
 import com.google.idea.blaze.qsync.project.ProjectProto;
 import com.google.idea.blaze.qsync.project.ProjectProto.LibrarySource;
-import com.google.idea.common.util.Transactions;
 import com.intellij.openapi.externalSystem.service.project.IdeModifiableModelsProvider;
 import com.intellij.openapi.externalSystem.service.project.ProjectDataManager;
 import com.intellij.openapi.module.Module;
@@ -116,7 +115,7 @@ public void onNewProjectSnapshot(Context<?> context, QuerySyncProjectSnapshot gr
 
   private void updateProjectModel(ProjectProto.Project spec, Context<?> context) {
     File imlDirectory = new File(BlazeDataStorage.getProjectDataDir(importSettings), "modules");
-    Transactions.submitWriteActionTransactionAndWait(
+    ProjectUpdaterThreadingUtils.Companion.readWriteAction(
         () -> {
           IdeModifiableModelsProvider models =
               ProjectDataManager.getInstance().createModifiableModelsProvider(project);
@@ -217,9 +216,10 @@ private void updateProjectModel(ProjectProto.Project spec, Context<?> context) {
                       .build(),
                   workspaceLanguageSettings);
             }
-            models.commit();
+
           }
-        });
+          return models;
+        }, models -> models.commit());
   }
 
   private Library getOrCreateLibrary(

base/src/com/google/idea/blaze/base/qsync/ProjectUpdaterThreadingUtils.kt

@@ -0,0 +1,33 @@
+package com.google.idea.blaze.base.qsync
+
+import com.google.idea.common.util.Transactions
+import com.intellij.openapi.application.readAndWriteAction
+import com.intellij.openapi.diagnostic.Logger
+import com.intellij.openapi.util.registry.Registry
+import kotlinx.coroutines.runBlocking
+import java.util.concurrent.Callable
+import java.util.function.Consumer
+
+class ProjectUpdaterThreadingUtils {
+    companion object {
+        val logger = Logger.getInstance(ProjectUpdaterThreadingUtils::class.java)
+        fun <T> readWriteAction(readPart: Callable<T>, commit: Consumer<T>) {
+            if (Registry.`is`("bazel.qsync.enable.coroutine.project.updater")) {
+                runBlocking {
+                    readAndWriteAction {
+                        logger.info("Starting read operation")
+                        val ret = readPart.call()
+                        writeAction {
+                            commit.accept(ret)
+                        }
+                    }
+                }
+            } else {
+                Transactions.submitWriteActionTransactionAndWait {
+                    val ret = readPart.call()
+                    commit.accept(ret)
+                }
+            }
+        }
+    }
+}