IDEA-76795 vcs: do not allow multiple processes to load same committed change details

platform/vcs-impl/src/com/intellij/openapi/vcs/impl/AbstractVcsHelperImpl.java

@@ -669,6 +669,12 @@ public class AbstractVcsHelperImpl extends AbstractVcsHelper {
     final CommittedChangeList[] list = new CommittedChangeList[1];
     final FilePath[] targetPath = new FilePath[1];
     final VcsException[] exc = new VcsException[1];
+
+    final BackgroundableActionLock lock = BackgroundableActionLock.getLock(project, VcsBackgroundableActions.COMMITTED_CHANGES_DETAILS,
+                                                                           revision, virtualFile.getPath());
+    if (lock.isLocked()) return;
+    lock.lock();
+
     Task.Backgroundable task = new Task.Backgroundable(project, title, true, BackgroundFromStartOption.getInstance()) {
       @Override
       public void run(@NotNull ProgressIndicator indicator) {
@@ -700,8 +706,14 @@ public class AbstractVcsHelperImpl extends AbstractVcsHelper {
         }
       }
 
+      @Override
+      public void onCancel() {
+        lock.unlock();
+      }
+
       @Override
       public void onSuccess() {
+        lock.unlock();
         if (exc[0] != null) {
           showError(exc[0], failedText(virtualFile, revision));
         }

platform/vcs-impl/src/com/intellij/openapi/vcs/impl/VcsBackgroundableActions.java

@@ -22,7 +22,8 @@ public enum VcsBackgroundableActions {
   ANNOTATE,
   COMPARE_WITH, // common for compare with (selected/latest/same) revision
   CREATE_HISTORY_SESSION,
-  HISTORY_FOR_SELECTION;
+  HISTORY_FOR_SELECTION,
+  COMMITTED_CHANGES_DETAILS;
 
   public static Object keyFrom(final FilePath filePath) {
     return filePath.getPath();