From 3e7881f35fdc02eb098ba94b9281fb4b80c80487 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 8 Jul 2015 13:29:16 -0500
Subject: [PATCH] Report extra metadata when screen lines are undefined when
 clipping

---
 src/display-buffer.coffee | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/display-buffer.coffee b/src/display-buffer.coffee
index 179795db5..d7dc236d6 100644
--- a/src/display-buffer.coffee
+++ b/src/display-buffer.coffee
@@ -890,6 +890,17 @@ class DisplayBuffer extends Model
       column = 0
 
     screenLine = @tokenizedLineForScreenRow(row)
+    unless screenLine?
+      error = new Error("Undefined screen line when clipping screen position")
+      Error.captureStackTrace(error)
+      error.metadata = {
+        screenRow: row
+        screenColumn: column
+        maxScreenRow: @getLastRow()
+        screenLinesDefined: @screenLines.map (sl) -> sl?
+      }
+      throw error
+
     maxScreenColumn = screenLine.getMaxScreenColumn()
 
     if screenLine.isSoftWrapped() and column >= maxScreenColumn