Merge pull request #8208 from atom/ns-defer-selection-merge

Defer selection merge until dragging completes

spec/text-editor-component-spec.coffee

@@ -1791,6 +1791,22 @@ describe "TextEditorComponent", ->
         expect(nextAnimationFrame).toBe noAnimationFrame
         expect(editor.getSelectedScreenRange()).toEqual [[2, 4], [6, 8]]
 
+      describe "when the command key is held down", ->
+        it "adds a new selection and selects to the nearest screen position, then merges intersecting selections when the mouse button is released", ->
+          editor.setSelectedScreenRange([[4, 4], [4, 9]])
+
+          linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([2, 4]), which: 1, metaKey: true))
+          linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([6, 8]), which: 1))
+          nextAnimationFrame()
+          expect(editor.getSelectedScreenRanges()).toEqual [[[4, 4], [4, 9]], [[2, 4], [6, 8]]]
+
+          linesNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenPosition([4, 6]), which: 1))
+          nextAnimationFrame()
+          expect(editor.getSelectedScreenRanges()).toEqual [[[4, 4], [4, 9]], [[2, 4], [4, 6]]]
+
+          linesNode.dispatchEvent(buildMouseEvent('mouseup', clientCoordinatesForScreenPosition([4, 6]), which: 1))
+          expect(editor.getSelectedScreenRanges()).toEqual [[[2, 4], [4, 9]]]
+
       describe "when the editor is destroyed while dragging", ->
         it "cleans up the handlers for window.mouseup and window.mousemove", ->
           linesNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenPosition([2, 4]), which: 1))
@@ -1948,10 +1964,12 @@ describe "TextEditorComponent", ->
           gutterNode.dispatchEvent(buildMouseEvent('mouseup', clientCoordinatesForScreenRowInGutter(6), metaKey: true))
           expect(editor.getSelectedScreenRanges()).toEqual [[[3, 0], [3, 2]], [[4, 0], [7, 0]]]
 
-        it "merges overlapping selections", ->
+        it "merges overlapping selections when the mouse button is released", ->
           gutterNode.dispatchEvent(buildMouseEvent('mousedown', clientCoordinatesForScreenRowInGutter(2), metaKey: true))
           gutterNode.dispatchEvent(buildMouseEvent('mousemove', clientCoordinatesForScreenRowInGutter(6), metaKey: true))
           nextAnimationFrame()
+          expect(editor.getSelectedScreenRanges()).toEqual [[[3, 0], [3, 2]], [[2, 0], [7, 0]]]
+
           gutterNode.dispatchEvent(buildMouseEvent('mouseup', clientCoordinatesForScreenRowInGutter(6), metaKey: true))
           expect(editor.getSelectedScreenRanges()).toEqual [[[2, 0], [7, 0]]]
 

src/text-editor-component.coffee

@@ -404,7 +404,7 @@ class TextEditorComponent
         @editor.getLastSelection().selectLine()
 
     @handleDragUntilMouseUp event, (screenPosition) =>
-      @editor.selectToScreenPosition(screenPosition)
+      @editor.selectToScreenPosition(screenPosition, true)
 
   onLineNumberGutterMouseDown: (event) =>
     return unless event.button is 0 # only handle the left mouse button
@@ -448,9 +448,6 @@ class TextEditorComponent
       else
         rowSelection.setBufferRange([[clickedBufferRow, 0], [dragBufferRow + 1, 0]], preserveFolds: true)
 
-      # After updating the selected screen range, merge overlapping selections
-      @editor.mergeIntersectingSelections(preserveFolds: true)
-
       # The merge process will possibly destroy the current selection because
       # it will be merged into another one. Therefore, we need to obtain a
       # reference to the new selection that contains the originally selected row
@@ -552,6 +549,7 @@ class TextEditorComponent
     onMouseUp = (event) =>
       stopDragging()
       @editor.finalizeSelections()
+      @editor.mergeIntersectingSelections()
       pasteSelectionClipboard(event)
 
     stopDragging = ->

src/text-editor.coffee

@@ -1948,10 +1948,11 @@ class TextEditor extends Model
   # This method may merge selections that end up intesecting.
   #
   # * `position` An instance of {Point}, with a given `row` and `column`.
-  selectToScreenPosition: (position) ->
+  selectToScreenPosition: (position, suppressMerge) ->
     lastSelection = @getLastSelection()
     lastSelection.selectToScreenPosition(position)
-    @mergeIntersectingSelections(reversed: lastSelection.isReversed())
+    unless suppressMerge
+      @mergeIntersectingSelections(reversed: lastSelection.isReversed())
 
   # Essential: Move the cursor of each selection one character upward while
   # preserving the selection's tail position.