java completion: supply same-named classes in batches for more deterministic sorting and preselection (IDEA-229266)

GitOrigin-RevId: 44c3e4a0f9a150082b1f3210b25f5b4c79f64e7f

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionContributor.java

@@ -527,11 +527,7 @@ public class JavaCompletionContributor extends CompletionContributor {
     }
 
     if (parameters.getInvocationCount() >= 2) {
-      JavaClassNameCompletionContributor.addAllClasses(parameters, parameters.getInvocationCount() <= 2, result.getPrefixMatcher(), element -> {
-        if (!session.alreadyProcessed(element)) {
-          result.addElement(JavaCompletionUtil.highlightIfNeeded(null, element, element.getObject(), parameters.getPosition()));
-        }
-      });
+      JavaNoVariantsDelegator.suggestNonImportedClasses(parameters, result, session);
     }
     else {
       advertiseSecondCompletion(parameters.getPosition().getProject(), result);

java/java-impl/src/com/intellij/codeInsight/completion/JavaNoVariantsDelegator.java

@@ -32,9 +32,7 @@ import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.Collections;
-import java.util.LinkedHashSet;
-import java.util.Set;
+import java.util.*;
 
 import static com.intellij.patterns.PsiJavaPatterns.psiElement;
 
@@ -196,18 +194,25 @@ public class JavaNoVariantsDelegator extends CompletionContributor {
     return allClasses;
   }
 
-  private static void suggestNonImportedClasses(CompletionParameters parameters, CompletionResultSet result, @Nullable JavaCompletionSession session) {
-    JavaClassNameCompletionContributor.addAllClasses(parameters, true, result.getPrefixMatcher(), element -> {
+  static void suggestNonImportedClasses(CompletionParameters parameters, CompletionResultSet result, @Nullable JavaCompletionSession session) {
+    List<LookupElement> sameNamedBatch = new ArrayList<>();
+    JavaClassNameCompletionContributor.addAllClasses(parameters, parameters.getInvocationCount() <= 2, result.getPrefixMatcher(), element -> {
       if (session != null && session.alreadyProcessed(element)) {
         return;
       }
       JavaPsiClassReferenceElement classElement = element.as(JavaPsiClassReferenceElement.CLASS_CONDITION_KEY);
-      if (classElement != null) {
+      if (classElement != null && parameters.getInvocationCount() < 2) {
         classElement.setAutoCompletionPolicy(AutoCompletionPolicy.NEVER_AUTOCOMPLETE);
       }
 
-      result.addElement(element);
+      element = JavaCompletionUtil.highlightIfNeeded(null, element, element.getObject(), parameters.getPosition());
+      if (!sameNamedBatch.isEmpty() && !element.getLookupString().equals(sameNamedBatch.get(0).getLookupString())) {
+        result.addAllElements(sameNamedBatch);
+        sameNamedBatch.clear();
+      }
+      sameNamedBatch.add(element);
     });
+    result.addAllElements(sameNamedBatch);
   }
 
   public static class ResultTracker implements Consumer<CompletionResult> {

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/CompletionSortingTestCase.java

@@ -5,6 +5,7 @@ import com.intellij.codeInsight.completion.CompletionType;
 import com.intellij.codeInsight.completion.LightFixtureCompletionTestCase;
 import com.intellij.codeInsight.completion.StatisticsUpdate;
 import com.intellij.codeInsight.lookup.LookupElement;
+import com.intellij.codeInsight.lookup.LookupEx;
 import com.intellij.codeInsight.lookup.impl.LookupImpl;
 import com.intellij.ide.ui.UISettings;
 import com.intellij.psi.statistics.StatisticsManager;
@@ -76,7 +77,7 @@ public abstract class CompletionSortingTestCase extends LightFixtureCompletionTe
     lookup.resort(true);
   }
 
-  protected static void imitateItemSelection(final LookupImpl lookup, final int index) {
+  protected static void imitateItemSelection(LookupEx lookup, final int index) {
     final LookupElement item = lookup.getItems().get(index);
     lookup.setCurrentItem(item);
     StatisticsUpdate.collectStatisticChanges(item);

java/java-tests/testSrc/com/intellij/java/codeInsight/completion/JavaAutoPopupTest.groovy

@@ -40,6 +40,8 @@ import com.intellij.psi.NavigatablePsiElement
 import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiJavaFile
 import com.intellij.psi.PsiMethod
+import com.intellij.psi.statistics.StatisticsManager
+import com.intellij.psi.statistics.impl.StatisticsManagerImpl
 import com.intellij.psi.util.InheritanceUtil
 import com.intellij.testFramework.TestModeFlags
 import com.intellij.testFramework.fixtures.CodeInsightTestUtil
@@ -1809,4 +1811,29 @@ ita<caret>
     assert firstItems.each { InheritanceUtil.isInheritor(it.object as PsiClass, List.name) }
   }
 
+  void "test prefer previously selected despite many namesakes"() {
+    ((StatisticsManagerImpl)StatisticsManager.getInstance()).enableStatistics(myFixture.getTestRootDisposable())
+
+    def count = 400
+    def toSelect = 390
+    for (i in 0..<count) {
+      myFixture.addClass("package p$i; public class MyClass {}")
+    }
+    myFixture.configureByText "a.java", "class C extends <caret>"
+    type 'MyCla'
+    myFixture.assertPreferredCompletionItems 0, Collections.nCopies(count, 'MyClass') as String[]
+
+    edt {
+      assert LookupElementPresentation.renderElement(myFixture.lookup.items[toSelect]).tailText == " p$toSelect"
+      CompletionSortingTestCase.imitateItemSelection(myFixture.lookup, toSelect)
+      myFixture.lookup.hideLookup(true)
+    }
+
+    type 's'
+    myFixture.assertPreferredCompletionItems 0, Collections.nCopies(count, 'MyClass') as String[]
+    edt {
+      assert LookupElementPresentation.renderElement(myFixture.lookup.items[0]).tailText == " p$toSelect"
+    }
+  }
+
 }