Run special assertion if editor.debugFindMaxLineLength is true

package.json

@@ -1,7 +1,7 @@
 {
   "name": "atom",
   "productName": "Atom",
-  "version": "0.108.0",
+  "version": "0.109.0",
   "description": "A hackable text editor for the 21st Century.",
   "main": "./src/browser/main.js",
   "repository": {
@@ -75,7 +75,7 @@
     "autosave": "0.14.0",
     "background-tips": "0.15.0",
     "bookmarks": "0.26.0",
-    "bracket-matcher": "0.47.0",
+    "bracket-matcher": "0.48.0",
     "command-palette": "0.24.0",
     "deprecation-cop": "0.7.0",
     "dev-live-reload": "0.31.0",
@@ -109,7 +109,7 @@
     "wrap-guide": "0.19.0",
 
     "language-c": "0.21.0",
-    "language-coffee-script": "0.22.0",
+    "language-coffee-script": "0.23.0",
     "language-css": "0.17.0",
     "language-gfm": "0.42.0",
     "language-git": "0.9.0",
@@ -117,7 +117,7 @@
     "language-html": "0.22.0",
     "language-hyperlink": "0.10.0",
     "language-java": "0.11.0",
-    "language-javascript": "0.30.0",
+    "language-javascript": "0.32.0",
     "language-json": "0.8.0",
     "language-less": "0.11.0",
     "language-make": "0.10.0",

spec/editor-component-spec.coffee

@@ -111,6 +111,22 @@ describe "EditorComponent", ->
       expect(component.lineNodeForScreenRow(3).offsetTop).toBe 3 * lineHeightInPixels
       expect(component.lineNodeForScreenRow(4).offsetTop).toBe 4 * lineHeightInPixels
 
+    it "updates the lines when lines are inserted or removed above the rendered row range", ->
+      node.style.height = 4.5 * lineHeightInPixels + 'px'
+      component.measureScrollView()
+      runSetImmediateCallbacks()
+      verticalScrollbarNode.scrollTop = 5 * lineHeightInPixels
+      verticalScrollbarNode.dispatchEvent(new UIEvent('scroll'))
+      buffer = editor.getBuffer()
+
+      buffer.insert([0, 0], '\n\n')
+      runSetImmediateCallbacks()
+      expect(component.lineNodeForScreenRow(3).textContent).toBe editor.lineForScreenRow(3).text
+
+      buffer.delete([[0, 0], [3, 0]])
+      runSetImmediateCallbacks()
+      expect(component.lineNodeForScreenRow(3).textContent).toBe editor.lineForScreenRow(3).text
+
     it "updates the top position of lines when the line height changes", ->
       initialLineHeightInPixels = editor.getLineHeightInPixels()
       component.setLineHeight(2)

src/display-buffer.coffee

@@ -1075,8 +1075,22 @@ class DisplayBuffer extends Model
         @longestScreenRow = maxLengthCandidatesStartRow + screenRow
         @maxLineLength = length
 
+    if atom.config.get('editor.debugFindMaxLineLength')
+      unless @maxLineLength is @findReferenceMaxLineLength()
+        debugger
+        throw new Error("Found wrong max line length")
+
     @computeScrollWidth() if oldMaxLineLength isnt @maxLineLength
 
+  findReferenceMaxLineLength: ->
+    maxLineLength = 0
+
+    for line in @screenLines
+      length = line.text.length
+      maxLineLength = length if length > maxLineLength
+
+    maxLineLength
+
   computeScrollWidth: ->
     @scrollWidth = @pixelPositionForScreenPosition([@longestScreenRow, @maxLineLength]).left + 1
 

src/lines-component.coffee

@@ -53,7 +53,10 @@ LinesComponent = React.createClass
     {renderedRowRange, pendingChanges} = newProps
     [renderedStartRow, renderedEndRow] = renderedRowRange
     for change in pendingChanges
-      return true unless change.end < renderedStartRow or renderedEndRow <= change.start
+      if change.screenDelta is 0
+        return true unless change.end < renderedStartRow or renderedEndRow <= change.start
+      else
+        return true unless renderedEndRow <= change.start
 
     false