From 31ceeec25244df305fba5a7a44838c15af39b95a Mon Sep 17 00:00:00 2001
From: Le Tan <tamlokveer@gmail.com>
Date: Mon, 19 Nov 2018 19:48:31 +0800
Subject: [PATCH] VTextDocumentLayout: add debug info for the crash

---
 src/vtextdocumentlayout.cpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/vtextdocumentlayout.cpp b/src/vtextdocumentlayout.cpp
index dd77c0c0..da60dbc7 100644
--- a/src/vtextdocumentlayout.cpp
+++ b/src/vtextdocumentlayout.cpp
@@ -447,14 +447,20 @@ void VTextDocumentLayout::documentChanged(int p_from, int p_charsRemoved, int p_
         // TODO: we may need one more next block.
         changeEndBlock = changeStartBlock;
     } else {
-        changeEndBlock = doc->findBlock(qMax(0, p_from + charsChanged));
+        changeEndBlock = doc->findBlock(p_from + charsChanged);
     }
 
+    qDebug() << "documentChanged" << p_from << p_charsRemoved << p_charsAdded
+             << m_blockCount << newBlockCount
+             << changeStartBlock.blockNumber() << changeEndBlock.blockNumber();
+
+    bool needRelayout = true;
     if (changeStartBlock == changeEndBlock
         && newBlockCount == m_blockCount) {
         // Change single block internal only.
         QTextBlock block = changeStartBlock;
         if (block.isValid() && block.length()) {
+            needRelayout = false;
             QRectF oldBr = blockBoundingRect(block);
             clearBlockLayout(block);
             layoutBlockAndUpdateOffset(block);
@@ -468,7 +474,9 @@ void VTextDocumentLayout::documentChanged(int p_from, int p_charsRemoved, int p_
                 return;
             }
         }
-    } else {
+    }
+
+    if (needRelayout) {
         QTextBlock block = changeStartBlock;
         do {
             clearBlockLayout(block);