[threading] IJPL-216787: Avoid deadlock with synchronous refresh invoked inside background write action

GitOrigin-RevId: e4a3a51cf17acf430cce38165377a7d7d06126a7

platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/RefreshQueueImpl.kt

@@ -70,7 +70,7 @@ class RefreshQueueImpl(coroutineScope: CoroutineScope) : RefreshQueue(), Disposa
         queueSession(session, session.modality)
       }
     }
-    else if (EDT.isCurrentThreadEdt()) {
+    else if (EDT.isCurrentThreadEdt() || ApplicationManager.getApplication().isWriteAccessAllowed) {
       (TransactionGuard.getInstance() as TransactionGuardImpl).assertWriteActionAllowed()
       val events = runRefreshSession(session, -1L)
       fireEvents(events, session)

platform/platform-tests/testSrc/com/intellij/openapi/vfs/newvfs/persistent/VfsRefreshTest.kt

@@ -231,4 +231,17 @@ class VfsRefreshTest {
     }
     assertEquals(currentCounter, newCounter, "There should be no write action if there was nothing to refresh")
   }
+
+  @Test
+  fun `synchronous refresh in a background write action can terminate successfully`() = timeoutRunBlocking {
+    val file = createTempFile()
+    val virtualFile = VirtualFileManager.getInstance().findFileByNioPath(file)!!
+    writeAction {
+      virtualFile.writeText("42")
+    }
+    backgroundWriteAction {
+      virtualFile.refresh(false, false)
+    }
+    // if this test terminates, there was no hanging
+  }
 }