Merge pull request #212 from atom/ns-as-fix-preceding-boundary-search

Fix preceding boundary calculation for changes inside of folds

spec/display-layer-spec.js

@@ -528,6 +528,21 @@ describe('DisplayLayer', () => {
         }
       }
     })
+
+    it('correctly updates the index for edits fully contained within multi-line folds that appear on soft-wrapped line segments', () => {
+      const buffer = new TextBuffer({
+        text: 'premillennial alcoholism\nelse\t\nastraphobia stereotomy\nbananas\n'
+      })
+      const displayLayer = buffer.addDisplayLayer({
+        tabLength: 4,
+        invisibles: {eol: '¬'},
+        softWrapColumn: 10
+      })
+      displayLayer.foldBufferRange([[0, 16], [1, 4]])
+      displayLayer.foldBufferRange([[1, 5], [3, 3]])
+      buffer.setTextInRange([[2, 16], [2, 21]], ' \nunderlinen\ncopybook\t')
+      expect(displayLayer.getText()).toBe('premillenn\nial al⋯ \n⋯anas¬\n')
+    })
   })
 
   describe('soft wraps', () => {

src/display-layer.js

@@ -999,16 +999,13 @@ class DisplayLayer {
 
   findBoundaryPrecedingBufferRow (bufferRow) {
     while (true) {
+      if (bufferRow === 0) return 0
       let screenPosition = this.translateBufferPositionWithSpatialIndex(Point(bufferRow, 0), 'backward')
-      if (screenPosition.column === 0) {
-        return this.translateScreenPositionWithSpatialIndex(screenPosition, 'backward').row
+      let bufferPosition = this.translateScreenPositionWithSpatialIndex(Point(screenPosition.row, 0), 'backward', false)
+      if (screenPosition.column === 0 && bufferPosition.column === 0) {
+        return bufferPosition.row
       } else {
-        let bufferPosition = this.translateScreenPositionWithSpatialIndex(Point(screenPosition.row, 0), 'backward', false)
-        if (bufferPosition.column === 0) {
-          return bufferPosition.row
-        } else {
-          bufferRow = bufferPosition.row
-        }
+        bufferRow = bufferPosition.row
       }
     }
   }