From 8d906207d44abe5b893eb8976c372c46e9cf8ebd Mon Sep 17 00:00:00 2001
From: Dmitry Jemerov <yole@jetbrains.com>
Date: Mon, 2 Jul 2018 15:35:39 +0200
Subject: [PATCH] Allow passing additional prefix to
 CompletionServiceImpl.handleCompletionItemSelected()

---
 ...CompletionServiceWithAdditionalPrefix.java | 20 +++++++++++++++++++
 .../completion/CompletionServiceTest.java     | 18 ++++++++++++++---
 .../impl/CompletionServiceImpl.java           |  4 +++-
 3 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/completion/normal/Simple_afterCompletionServiceWithAdditionalPrefix.java

diff --git a/java/java-tests/testData/codeInsight/completion/normal/Simple_afterCompletionServiceWithAdditionalPrefix.java b/java/java-tests/testData/codeInsight/completion/normal/Simple_afterCompletionServiceWithAdditionalPrefix.java
new file mode 100644
index 000000000000..c6fb2a7eee7c
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/normal/Simple_afterCompletionServiceWithAdditionalPrefix.java
@@ -0,0 +1,20 @@
+class A extends Base{
+  int _field;
+  void _method(){}
+
+  void foo(){
+    int _local1;
+    int _local2;
+    _local1
+    int _local3;
+  }
+}
+
+class Base{
+  void _baseMethod(){}
+  int _baseField;
+
+  private void privateMethod(){}
+  private int privateField;
+}
+
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/CompletionServiceTest.java b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/CompletionServiceTest.java
index 935f847c0b49..65ea33cd0f28 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/CompletionServiceTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/CompletionServiceTest.java
@@ -28,6 +28,17 @@ public class CompletionServiceTest extends LightCodeInsightFixtureTestCase {
 
   public void testCompletionServiceSimple() {
     myFixture.configureByFile("Simple.java");
+    doCompletionServiceTest("_field", "");
+    myFixture.checkResultByFile("Simple_afterCompletionService.java");
+  }
+
+  public void testCompletionServiceWithPrefix() {
+    myFixture.configureByFile("Simple.java");
+    doCompletionServiceTest("_local1", "loc");
+    myFixture.checkResultByFile("Simple_afterCompletionServiceWithAdditionalPrefix.java");
+  }
+
+  public void doCompletionServiceTest(String lookupItemText, String additionalPrefix) {
     CompletionServiceImpl service = (CompletionServiceImpl)CompletionService.getCompletionService();
     Disposable completionDisposable = Disposer.newDisposable();
     try {
@@ -41,9 +52,10 @@ public class CompletionServiceTest extends LightCodeInsightFixtureTestCase {
       CompletionLookupArranger arranger = service.createLookupArranger(parameters);
       service.performCompletion(parameters, result -> arranger.addElement(result));
       Pair<List<LookupElement>, Integer> items = arranger.arrangeItems();
-      LookupElement element = ContainerUtil.find(items.first, item -> item.getLookupString().equals("_field"));
-      WriteCommandAction.runWriteCommandAction(getProject(), () -> service.handleCompletionItemSelected(parameters, element, arranger.itemMatcher(element), '\n'));
-      myFixture.checkResultByFile("Simple_afterCompletionService.java");
+      LookupElement element = ContainerUtil.find(items.first, item -> item.getLookupString().equals(lookupItemText));
+      myFixture.type(additionalPrefix);
+      WriteCommandAction.runWriteCommandAction(getProject(), () -> service.handleCompletionItemSelected(parameters, element, arranger.itemMatcher(element),
+                                                                                                        additionalPrefix, '\n'));
     }
     finally {
       Disposer.dispose(completionDisposable);
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CompletionServiceImpl.java b/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CompletionServiceImpl.java
index 6d2d8da261d9..99829373fd34 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CompletionServiceImpl.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/completion/impl/CompletionServiceImpl.java
@@ -292,12 +292,14 @@ public final class CompletionServiceImpl extends CompletionService {
   public void handleCompletionItemSelected(CompletionParameters parameters,
                                            LookupElement lookupElement,
                                            PrefixMatcher prefixMatcher,
+                                           String additionalPrefix,
                                            char completionChar) {
 
+    String itemPattern = prefixMatcher.getPrefix() + additionalPrefix;
     LookupImpl.insertLookupString(parameters.getPosition().getProject(),
                                   parameters.getEditor(),
                                   lookupElement,
-                                  prefixMatcher, prefixMatcher.getPrefix(), prefixMatcher.getPrefix().length());
+                                  prefixMatcher, itemPattern, itemPattern.length());
     CodeCompletionHandlerBase handler =
       CodeCompletionHandlerBase.createHandler(parameters.getCompletionType(), true, parameters.isAutoPopup(), true);
     handler.handleCompletionElementSelected(parameters, lookupElement, completionChar);