From f1b217be4c7e352053fe6a40cdbcfecb111ba268 Mon Sep 17 00:00:00 2001
From: Alexey Kudravtsev <cdr@intellij.com>
Date: Tue, 6 Nov 2018 18:12:10 +0300
Subject: [PATCH] fail fast when creating range marker with invalid offsets
 from virtual file in presence of cached document

---
 .../openapi/editor/impl/RangeMarkerImpl.java  |  7 +++++-
 .../openapi/editor/impl/RangeMarkerTest.java  | 23 ++++++++++++++++---
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/platform/core-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java b/platform/core-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
index 9ce029401890..3dc0b523c717 100644
--- a/platform/core-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
+++ b/platform/core-impl/src/com/intellij/openapi/editor/impl/RangeMarkerImpl.java
@@ -54,7 +54,12 @@ public class RangeMarkerImpl extends UserDataHolderBase implements RangeMarkerEx
   // constructor which creates marker without document and saves it in the virtual file directly. Can be cheaper than loading document.
   RangeMarkerImpl(@NotNull VirtualFile virtualFile, int start, int end, boolean register) {
     // unfortunately we don't know the exact document size until we load it
-    this(virtualFile, Integer.MAX_VALUE, start, end, register, false, false);
+    this(virtualFile, estimateDocumentLength(virtualFile), start, end, register, false, false);
+  }
+
+  private static int estimateDocumentLength(@NotNull VirtualFile virtualFile) {
+    Document document = FileDocumentManager.getInstance().getCachedDocument(virtualFile);
+    return document == null ? Integer.MAX_VALUE : document.getTextLength();
   }
 
   private RangeMarkerImpl(@NotNull Object documentOrFile, int documentTextLength, int start,
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
index ca156814357e..79ec24d40510 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/RangeMarkerTest.java
@@ -1112,22 +1112,39 @@ public class RangeMarkerTest extends LightPlatformTestCase {
     marker.dispose();
   }
 
-  public void testLazyRangeMarkersWithInvalidOffset() {
+  public void testLazyRangeMarkersWithInvalidOffsetWhenNoDocumentCreatedMustInvalidateThemSelvesOnFirstOpportunity() {
     psiFile = createFile("x.txt", "");
 
     LazyRangeMarkerFactoryImpl factory = (LazyRangeMarkerFactoryImpl)LazyRangeMarkerFactory.getInstance(getProject());
     VirtualFile virtualFile = psiFile.getVirtualFile();
-    Document document = FileDocumentManager.getInstance().getDocument(virtualFile);
 
-    assertEquals("", document.getText());
+    assertEquals("", psiFile.getText());
 
     RangeMarker marker = factory.createRangeMarker(virtualFile, 1 /* invalid offset */);
 
+    document = FileDocumentManager.getInstance().getDocument(virtualFile);
     document.replaceString(0, 0, "\n\t\n");  // used to throw AssertionError from RangeMarkerTree.updateMarkersOnChange
     assertEquals("\n\t\n", document.getText());
     assertFalse(marker.isValid());
   }
 
+  public void testLazyRangeMarkersWithInvalidOffsetWhenCachedDocumentAlreadyExistsMustRejectInvalidOffsetsRightAway() {
+    psiFile = createFile("x.txt", "");
+
+    LazyRangeMarkerFactoryImpl factory = (LazyRangeMarkerFactoryImpl)LazyRangeMarkerFactory.getInstance(getProject());
+    VirtualFile virtualFile = psiFile.getVirtualFile();
+    document = FileDocumentManager.getInstance().getDocument(virtualFile);
+
+    assertEquals("", psiFile.getText());
+
+    try {
+      factory.createRangeMarker(virtualFile, 1 /* invalid offset */);
+      fail("Must fail fast");
+    }
+    catch (IllegalArgumentException ignored) {
+    }
+  }
+
   public void testNonGreedyMarkersGrowOnAppendingReplace() {
     Document doc = new DocumentImpl("foo");
     RangeMarker marker = doc.createRangeMarker(0, 3);