completion copy should be reparsed incrementally even for big files (IDEA-129815)

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

@@ -23,10 +23,12 @@ import com.intellij.codeInsight.lookup.LookupManager
 import com.intellij.codeInsight.lookup.impl.LookupImpl
 import com.intellij.lang.java.JavaLanguage
 import com.intellij.openapi.actionSystem.IdeActions
+import com.intellij.psi.PsiClass
 import com.intellij.psi.PsiDocumentManager
 import com.intellij.psi.PsiMethod
 import com.intellij.psi.codeStyle.CodeStyleSettingsManager
 import com.intellij.psi.codeStyle.CommonCodeStyleSettings
+import com.intellij.psi.impl.PsiDocumentManagerBase
 import com.siyeh.ig.style.UnqualifiedFieldAccessInspection
 
 public class NormalCompletionTest extends LightFixtureCompletionTestCase {
@@ -1515,4 +1517,23 @@ class Bar {
   }
   
   public void testIndentingForSwitchCase() { doTest() }
+
+  public void testIncrementalCopyReparse() {
+    ((PsiDocumentManagerBase)PsiDocumentManager.getInstance(project)).disableBackgroundCommit(testRootDisposable)
+    
+    myFixture.configureByText('a.java', 'class Fooxxxxxxxxxx { Fooxxxxx<caret>a f;\n' + 'public void foo() {}\n' * 10000 + '}')
+    def items = myFixture.completeBasic()
+    PsiClass c1 = items[0].object
+    assert !c1.physical
+    assert CompletionUtil.getOriginalElement(c1)
+    
+    getLookup().hide()
+    myFixture.type('x')
+    items = myFixture.completeBasic()
+    PsiClass c2 = items[0].object
+    assert !c2.physical
+    assert CompletionUtil.getOriginalElement(c2)
+
+    assert c1.is(c2)
+  }
 }

platform/core-impl/src/com/intellij/openapi/editor/impl/DocumentImpl.java

@@ -499,7 +499,7 @@ public class DocumentImpl extends UserDataHolderBase implements DocumentEx {
 
   @Override
   public void replaceString(int startOffset, int endOffset, @NotNull CharSequence s) {
-    replaceString(startOffset, endOffset, s, LocalTimeCounter.currentTime(), startOffset == 0 && endOffset == getTextLength());
+    replaceString(startOffset, endOffset, s, LocalTimeCounter.currentTime(), false);
   }
 
   private void replaceString(int startOffset, int endOffset, @NotNull CharSequence s, final long newModificationStamp, boolean wholeTextReplaced) {

platform/core-impl/src/com/intellij/openapi/editor/impl/event/DocumentEventImpl.java

@@ -152,7 +152,7 @@ public class DocumentEventImpl extends DocumentEvent {
 
   @Override
   public boolean isWholeTextReplaced() {
-    return myIsWholeDocReplaced;
+    return myIsWholeDocReplaced || super.isWholeTextReplaced();
   }
 
   public int translateLineViaDiff(int line) throws FilesTooBigForDiffException {

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

@@ -777,7 +777,7 @@ public class CodeCompletionHandlerBase {
         Document originalDocument = file.getViewProvider().getDocument();
         assert originalDocument != null;
         assert originalDocument.getTextLength() == file.getTextLength() : originalDocument;
-        document.setText(originalDocument.getImmutableCharSequence());
+        document.replaceString(0, document.getTextLength(), originalDocument.getImmutableCharSequence());
         return copy;
       }
     }