Fix importUsers concurrency issues

Author: zolotov

src/com/goide/codeInsight/imports/GoImportOptimizer.java

@@ -127,17 +127,8 @@ public static MultiMap<String, GoImportSpec> filterUnusedImports(@NotNull PsiFil
     Collection<GoImportSpec> implicitImports = ContainerUtil.newArrayList(result.get("."));
     for (GoImportSpec importEntry : implicitImports) {
       GoImportSpec spec = getImportSpec(importEntry);
-      if (spec != null && spec.isDot()) {
-        List<? extends PsiElement> list = spec.getUserData(GoReferenceBase.IMPORT_USERS);
-        if (list != null) {
-          for (PsiElement e : list) {
-            if (e.isValid()) {
-              result.remove(".", importEntry);
-              break;
-            }
-            ProgressManager.checkCanceled();
-          }
-        }
+      if (spec != null && spec.isDot() && hasImportUsers(spec)) {
+        result.remove(".", importEntry);
       }
     }
 
@@ -194,8 +185,24 @@ private void markAsUsed(@NotNull PsiElement qualifier, @NotNull PsiReference ref
     return result;
   }
 
+  private static boolean hasImportUsers(@NotNull GoImportSpec spec) {
+    //noinspection SynchronizationOnLocalVariableOrMethodParameter
+    synchronized (spec) {
+      List<PsiElement> list = spec.getUserData(GoReferenceBase.IMPORT_USERS);
+      if (list != null) {
+        for (PsiElement e : list) {
+          if (e.isValid()) {
+            return true;
+          }
+          ProgressManager.checkCanceled();
+        }
+      }
+    }
+    return false;
+  }
+
   @NotNull
-  public static Set<GoImportSpec> findDuplicatedEntries(@NotNull MultiMap<String, GoImportSpec> importMap) {
+  private static Set<GoImportSpec> findDuplicatedEntries(@NotNull MultiMap<String, GoImportSpec> importMap) {
     Set<GoImportSpec> duplicatedEntries = ContainerUtil.newLinkedHashSet();
     for (Map.Entry<String, Collection<GoImportSpec>> imports : importMap.entrySet()) {
       Collection<GoImportSpec> importsWithSameName = imports.getValue();

src/com/goide/highlighting/GoHighlightingAnnotator.java

@@ -32,6 +32,7 @@
 import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 import static com.goide.highlighting.GoSyntaxHighlightingColors.*;
 
@@ -137,15 +138,14 @@ private static boolean isPackageWide(@NotNull GoConstDefinition o) {
   public void annotate(@NotNull PsiElement o, @NotNull AnnotationHolder holder) {
     if (!o.isValid()) return;
     if (o instanceof GoImportSpec && ((GoImportSpec)o).isDot()) {
-      List<? extends PsiElement> importUsers = o.getUserData(GoReferenceBase.IMPORT_USERS);
-      if (importUsers != null) {
-        List<PsiElement> newImportUsers = ContainerUtil.newSmartList();
-        for (PsiElement user : importUsers) {
-          if (user.isValid()) {
-            newImportUsers.add(user);
-          }
+      //noinspection SynchronizationOnLocalVariableOrMethodParameter
+      synchronized (o) {
+        List<PsiElement> importUsers = o.getUserData(GoReferenceBase.IMPORT_USERS);
+        if (importUsers != null) {
+          List<PsiElement> newImportUsers = ContainerUtil.newSmartList();
+          newImportUsers.addAll(importUsers.stream().filter(PsiElement::isValid).collect(Collectors.toList()));
+          o.putUserData(GoReferenceBase.IMPORT_USERS, newImportUsers.isEmpty() ? null : newImportUsers);
         }
-        o.putUserData(GoReferenceBase.IMPORT_USERS, newImportUsers.isEmpty() ? null : newImportUsers);
       }
     }
     else if (o instanceof GoLiteral) {

src/com/goide/psi/impl/GoReferenceBase.java

@@ -37,7 +37,7 @@
 import static com.goide.psi.impl.GoPsiImplUtil.allowed;
 
 public abstract class GoReferenceBase<T extends GoReferenceExpressionBase> extends PsiPolyVariantReferenceBase<T> {
-  public static final Key<List<? extends PsiElement>> IMPORT_USERS = Key.create("IMPORT_USERS");
+  public static final Key<List<PsiElement>> IMPORT_USERS = Key.create("IMPORT_USERS");
   public static final Key<String> ACTUAL_NAME = Key.create("ACTUAL_NAME");
 
   public GoReferenceBase(T element, TextRange range) {
@@ -51,13 +51,13 @@ protected static String getPath(@Nullable PsiFile file) {
     return virtualFile == null ? null : virtualFile.getPath();
   }
 
-  private static void putIfAbsent(@NotNull PsiElement importElement, @NotNull PsiElement usage) {
-    List<PsiElement> newList = ContainerUtil.newSmartList(usage);
-    List<? extends PsiElement> list = importElement.getUserData(IMPORT_USERS);
-    if (list != null) {
-      newList.addAll(list);
+  private static void putIfAbsent(@NotNull GoImportSpec importSpec, @NotNull PsiElement usage) {
+    //noinspection SynchronizationOnLocalVariableOrMethodParameter
+    synchronized (importSpec) {
+      List<PsiElement> newUsages = ContainerUtil.newSmartList(usage);
+      newUsages.addAll(IMPORT_USERS.get(importSpec, ContainerUtil.emptyList()));
+      importSpec.putUserData(IMPORT_USERS, newUsages);
     }
-    importElement.putUserData(IMPORT_USERS, newList);
   }
 
   protected boolean processDirectory(@Nullable PsiDirectory dir,