undo after template: don't insert second space (IDEA-153669)

java/java-tests/testData/refactoring/inplaceIntroduceVariable/undoPositionAfterSpace.java

@@ -0,0 +1,6 @@
+class Test {
+    void simpleMethod() {
+        int x = 0;
+        int k = <caret>1;
+    }
+}

java/java-tests/testSrc/com/intellij/refactoring/InplaceReassignVariableTest.java

@@ -17,6 +17,9 @@ package com.intellij.refactoring;
 
 import com.intellij.codeInsight.template.impl.TemplateManagerImpl;
 import com.intellij.codeInsight.template.impl.TemplateState;
+import com.intellij.openapi.command.undo.UndoManager;
+import com.intellij.openapi.fileEditor.TextEditor;
+import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider;
 import com.intellij.refactoring.introduceVariable.ReassignVariableUtil;
 
 public class InplaceReassignVariableTest extends AbstractJavaInplaceIntroduceTest {
@@ -34,6 +37,10 @@ public class InplaceReassignVariableTest extends AbstractJavaInplaceIntroduceTes
     doTest();
   }
 
+  public void testUndoPositionAfterSpace() throws Exception {
+    doUndoTest();
+  }
+
   private void doTest() {
     String name = getTestName(true);
     configureByFile(getBasePath() + name + getExtension());
@@ -55,6 +62,32 @@ public class InplaceReassignVariableTest extends AbstractJavaInplaceIntroduceTes
     }
   }
 
+  private void doUndoTest() {
+    String name = getTestName(true);
+    configureByFile(getBasePath() + name + getExtension());
+    final boolean enabled = getEditor().getSettings().isVariableInplaceRenameEnabled();
+    try {
+      TemplateManagerImpl.setTemplateTesting(getProject(), getTestRootDisposable());
+      getEditor().getSettings().setVariableInplaceRenameEnabled(true);
+
+      invokeRefactoring();
+      ReassignVariableUtil.reassign(getEditor());
+
+      TemplateState state = TemplateManagerImpl.getTemplateState(getEditor());
+      assert state != null;
+      state.gotoEnd(false);
+
+      TextEditor textEditor = TextEditorProvider.getInstance().getTextEditor(getEditor());
+      assertNotNull(textEditor);
+      UndoManager.getInstance(getProject()).undo(textEditor);
+
+      checkResultByFile(getBasePath() + name + getExtension());
+    }
+    finally {
+      getEditor().getSettings().setVariableInplaceRenameEnabled(enabled);
+    }
+  }
+
   @Override
   protected String getBasePath() {
     return "/refactoring/inplaceIntroduceVariable/";

platform/lang-impl/src/com/intellij/refactoring/introduce/inplace/InplaceVariableIntroducer.java

@@ -33,10 +33,7 @@ import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.TextRange;
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiNamedElement;
-import com.intellij.psi.SmartPointerManager;
-import com.intellij.psi.SmartPsiElementPointer;
+import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.SuggestedNameInfo;
 import com.intellij.psi.impl.source.PostprocessReformattingAspect;
 import com.intellij.refactoring.rename.NameSuggestionProvider;
@@ -77,8 +74,9 @@ public abstract class InplaceVariableIntroducer<E extends PsiElement> extends In
     if (expr != null) {
       final ASTNode node = expr.getNode();
       ASTNode prev = node.getTreePrev();
-      final ASTNode astNode = LanguageTokenSeparatorGenerators.INSTANCE.forLanguage(expr.getLanguage())
-        .generateWhitespaceBetweenTokens(prev, node);
+      final ASTNode astNode = prev instanceof PsiWhiteSpace ? null :
+                              LanguageTokenSeparatorGenerators.INSTANCE.forLanguage(expr.getLanguage())
+                                .generateWhitespaceBetweenTokens(prev, node);
       if (astNode != null) {
         final Lexer lexer = LanguageParserDefinitions.INSTANCE.forLanguage(expr.getLanguage()).createLexer(project);
         if (LanguageUtil.canStickTokensTogetherByLexer(prev, prev, lexer) == ParserDefinition.SpaceRequirements.MUST) {