From 2b6973d4b1cd25e6fdf82b0c32e7fb2616b8d7dc Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 30 Sep 2015 17:44:26 +0200
Subject: [PATCH] Fix a :bug: where some invalid lines were being measured

---
 spec/text-editor-presenter-spec.coffee | 24 ++++++++++++++++++++++++
 src/text-editor-presenter.coffee       | 15 ++++-----------
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/spec/text-editor-presenter-spec.coffee b/spec/text-editor-presenter-spec.coffee
index edec7eff2..88b26d62d 100644
--- a/spec/text-editor-presenter-spec.coffee
+++ b/spec/text-editor-presenter-spec.coffee
@@ -102,6 +102,30 @@ describe "TextEditorPresenter", ->
 
         expect(stateFn(presenter).tiles[12]).toBeUndefined()
 
+      it "includes state for tiles containing screen rows to measure", ->
+        presenter = buildPresenter(explicitHeight: 6, scrollTop: 0, lineHeight: 1, tileSize: 2)
+        presenter.setScreenRowsToMeasure([10, 12])
+
+        expect(stateFn(presenter).tiles[0]).toBeDefined()
+        expect(stateFn(presenter).tiles[2]).toBeDefined()
+        expect(stateFn(presenter).tiles[4]).toBeDefined()
+        expect(stateFn(presenter).tiles[6]).toBeDefined()
+        expect(stateFn(presenter).tiles[8]).toBeUndefined()
+        expect(stateFn(presenter).tiles[10]).toBeDefined()
+        expect(stateFn(presenter).tiles[12]).toBeDefined()
+
+      it "excludes invalid tiles for screen rows to measure", ->
+        presenter = buildPresenter(explicitHeight: 6, scrollTop: 0, lineHeight: 1, tileSize: 2)
+        presenter.setScreenRowsToMeasure([20, 30]) # unexisting rows
+
+        expect(stateFn(presenter).tiles[0]).toBeDefined()
+        expect(stateFn(presenter).tiles[2]).toBeDefined()
+        expect(stateFn(presenter).tiles[4]).toBeDefined()
+        expect(stateFn(presenter).tiles[6]).toBeDefined()
+        expect(stateFn(presenter).tiles[8]).toBeUndefined()
+        expect(stateFn(presenter).tiles[10]).toBeUndefined()
+        expect(stateFn(presenter).tiles[12]).toBeUndefined()
+
       it "includes state for all tiles if no external ::explicitHeight is assigned", ->
         presenter = buildPresenter(explicitHeight: null, tileSize: 2)
         expect(stateFn(presenter).tiles[0]).toBeDefined()
diff --git a/src/text-editor-presenter.coffee b/src/text-editor-presenter.coffee
index 92eadb6db..3d7298bcf 100644
--- a/src/text-editor-presenter.coffee
+++ b/src/text-editor-presenter.coffee
@@ -30,6 +30,7 @@ class TextEditorPresenter
     @lineDecorationsByScreenRow = {}
     @lineNumberDecorationsByScreenRow = {}
     @customGutterDecorationsByGutterNameAndScreenRow = {}
+    @screenRowsToMeasure = []
     @transferMeasurementsToModel()
     @transferMeasurementsFromModel()
     @observeModel()
@@ -370,8 +371,8 @@ class TextEditorPresenter
     screenRows = [startRow...endRow]
     if longestScreenRow = @model.getLongestScreenRow()
       screenRows.push(longestScreenRow)
-    if @screenRowsToMeasure?
-      screenRows.push(@screenRowsToMeasure...)
+    for row in @screenRowsToMeasure when @constrainRow(row) is row
+      screenRows.push(row)
 
     screenRows.sort (a, b) -> a - b
     _.uniq(screenRows, true)
@@ -384,14 +385,6 @@ class TextEditorPresenter
     @shouldUpdateLineNumbersState = true
     @shouldUpdateDecorations = true
 
-  clearScreenRowsToMeasure: ->
-    return if not screenRows? or screenRows.length is 0
-
-    @screenRowsToMeasure = []
-    @shouldUpdateLinesState = true
-    @shouldUpdateLineNumbersState = true
-    @shouldUpdateDecorations = true
-
   updateTilesState: ->
     return unless @startRow? and @endRow? and @lineHeight?
 
@@ -403,7 +396,7 @@ class TextEditorPresenter
     zIndex = 0
 
     for tileStartRow in [@tileForRow(endRow)..@tileForRow(startRow)] by -@tileSize
-      tileEndRow = Math.min(@model.getScreenLineCount(), tileStartRow + @tileSize)
+      tileEndRow = @constrainRow(tileStartRow + @tileSize)
       rowsWithinTile = []
 
       while screenRowIndex >= 0