IDEA-94821 Don't autoinsert a single completion item if it's provided via middle matching

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

@@ -17,6 +17,7 @@ package com.intellij.codeInsight.completion;
 
 import com.intellij.codeInsight.lookup.LookupElementBuilder;
 import com.intellij.openapi.util.Iconable;
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.util.PsiFormatUtil;
 import com.intellij.psi.util.PsiFormatUtilBase;
@@ -82,8 +83,12 @@ public class JavaLookupElementBuilder {
   public static LookupElementBuilder forClass(@NotNull PsiClass psiClass,
                                               final String lookupString,
                                               final boolean withLocation) {
-    final LookupElementBuilder builder =
+    LookupElementBuilder builder =
       LookupElementBuilder.create(psiClass, lookupString).withIcon(psiClass.getIcon(Iconable.ICON_FLAG_VISIBILITY));
+    String name = psiClass.getName();
+    if (StringUtil.isNotEmpty(name)) {
+      builder = builder.withLookupString(name);
+    }
     if (withLocation) {
       return builder.withTailText(" (" + PsiFormatUtil.getPackageDisplayName(psiClass) + ")", true);
     }

java/java-tests/testData/codeInsight/completion/normal/DontAutoInsertMiddleMatch.java

@@ -0,0 +1,5 @@
+public class A {
+  void foo(Foo myXxxxxxxxx) {
+    Xxxxx<caret>
+  }
+}

java/java-tests/testData/codeInsight/completion/normal/DontAutoInsertMiddleMatch_after.java

@@ -0,0 +1,5 @@
+public class A {
+  void foo(Foo myXxxxxxxxx) {
+    Xxxxx<caret>
+  }
+}

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

@@ -1310,5 +1310,11 @@ public class ListUtils {
     assert myFixture.lookupElementStrings.containsAll(['foo', 'bar'])
   }
 
+  public void testDontAutoInsertMiddleMatch() {
+    configure()
+    checkResult()
+    assert lookup.items.size() == 1
+  }
+
 
 }

platform/lang-impl/src/com/intellij/codeInsight/completion/CodeCompletionHandlerBase.java

@@ -395,6 +395,7 @@ public class CodeCompletionHandlerBase {
       final AutoCompletionPolicy policy = getAutocompletionPolicy(item);
       if (policy == AutoCompletionPolicy.NEVER_AUTOCOMPLETE) return AutoCompletionDecision.SHOW_LOOKUP;
       if (policy == AutoCompletionPolicy.ALWAYS_AUTOCOMPLETE) return AutoCompletionDecision.insertItem(item);
+      if (!indicator.getLookup().itemMatcher(item).isStartMatch(item)) return AutoCompletionDecision.SHOW_LOOKUP;
     }
     if (!isAutocompleteOnInvocation(parameters.getCompletionType())) {
       return AutoCompletionDecision.SHOW_LOOKUP;

platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CamelHumpMatcher.java

@@ -5,11 +5,13 @@ import com.intellij.codeInsight.CodeInsightSettings;
 import com.intellij.codeInsight.completion.PrefixMatcher;
 import com.intellij.codeInsight.lookup.LookupElement;
 import com.intellij.openapi.Disposable;
+import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Disposer;
 import com.intellij.openapi.util.registry.Registry;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.codeStyle.MinusculeMatcher;
 import com.intellij.psi.codeStyle.NameUtil;
+import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.TestOnly;
 
@@ -18,6 +20,7 @@ import org.jetbrains.annotations.TestOnly;
 */
 public class CamelHumpMatcher extends PrefixMatcher {
   private final MinusculeMatcher myMatcher;
+  private final MinusculeMatcher myCaseInsensitiveMatcher;
   private final boolean myCaseSensitive;
   private static boolean ourForceStartMatching;
 
@@ -30,6 +33,7 @@ public class CamelHumpMatcher extends PrefixMatcher {
     super(prefix);
     myCaseSensitive = caseSensitive;
     myMatcher = createMatcher(myCaseSensitive);
+    myCaseInsensitiveMatcher = createMatcher(false);
   }
 
   @Override
@@ -37,6 +41,22 @@ public class CamelHumpMatcher extends PrefixMatcher {
     return myMatcher.isStartMatch(name);
   }
 
+  @Override
+  public boolean isStartMatch(LookupElement element) {
+    if (super.isStartMatch(element)) {
+      return true;
+    }
+    if (element.isCaseSensitive()) {
+      return false;
+    }
+    return ContainerUtil.or(element.getAllLookupStrings(), new Condition<String>() {
+      @Override
+      public boolean value(String s) {
+        return myCaseInsensitiveMatcher.isStartMatch(s);
+      }
+    });
+  }
+
   @Override
   public boolean prefixMatches(@NotNull final String name) {
     return myMatcher.matches(name);
@@ -53,7 +73,7 @@ public class CamelHumpMatcher extends PrefixMatcher {
         return true;
       }
       if (itemCaseInsensitive && CodeInsightSettings.ALL != CodeInsightSettings.getInstance().COMPLETION_CASE_SENSITIVE) {
-        if (createMatcher(false).matches(name)) {
+        if (myCaseInsensitiveMatcher.matches(name)) {
           return true;
         }
       }