Update autocomplete position when populating list

Previously if the list was displayed above the cursor
position and the list was filtered to decrease in size
it would be displayed several rows above the cursor as
it shrinks.

Now the position is updated each time the list is populated
so it will always use the latest height when calculating
the position in the editor to place the select list at.

src/packages/autocomplete/spec/autocomplete-spec.coffee

@@ -364,6 +364,26 @@ describe "Autocomplete", ->
         expect(autocompleteBottom).toBe cursorPixelPosition.top
         expect(autocomplete.position().left).toBe cursorPixelPosition.left
 
+      it "updates the position when the list is filtered and the height of the list decreases", ->
+        editor.setCursorScreenPosition([11, 0])
+        editor.insertText('s')
+        editor.setCursorScreenPosition([11, 0])
+        cursorPixelPosition = editor.pixelPositionForScreenPosition(editor.getCursorScreenPosition())
+        autocomplete.attach()
+
+        expect(autocomplete.parent()).toExist()
+        autocompleteBottom = autocomplete.position().top + autocomplete.outerHeight()
+        expect(autocompleteBottom).toBe cursorPixelPosition.top
+        expect(autocomplete.position().left).toBe cursorPixelPosition.left
+
+        miniEditor.textInput('sh')
+        window.advanceClock(autocomplete.inputThrottle)
+
+        expect(autocomplete.parent()).toExist()
+        autocompleteBottom = autocomplete.position().top + autocomplete.outerHeight()
+        expect(autocompleteBottom).toBe cursorPixelPosition.top
+        expect(autocomplete.position().left).toBe cursorPixelPosition.left
+
   describe ".cancel()", ->
     it "clears the mini-editor and unbinds autocomplete event handlers for move-up and move-down", ->
       autocomplete.attach()

src/packages/autocomplete/src/autocomplete.coffee

@@ -16,6 +16,8 @@ class Autocomplete extends SelectList
   wordList: null
   wordRegex: /\w+/g
   originalSelectionBufferRange: null
+  originalCursorPosition: null
+  aboveCursor: false
   undoCount: 0
   filterKey: 'word'
 
@@ -82,8 +84,9 @@ class Autocomplete extends SelectList
 
   attach: ->
     @undoCount = 0
+    @aboveCursor = false
     @originalSelectionBufferRange = @editor.getSelection().getBufferRange()
-    originalCursorPosition = @editor.getCursorScreenPosition()
+    @originalCursorPosition = @editor.getCursorScreenPosition()
 
     @buildWordList()
     matches = @findMatchesForCurrentSelection()
@@ -93,7 +96,7 @@ class Autocomplete extends SelectList
       @confirmSelection()
     else
       @editor.appendToLinesView(this)
-      @setPosition(originalCursorPosition)
+      @setPosition()
     @miniEditor.focus()
 
   detach: ->
@@ -102,19 +105,19 @@ class Autocomplete extends SelectList
     @editor.off(".autocomplete")
     @editor.focus()
 
-  setPosition: (originalCursorPosition) ->
-    { left, top } = @editor.pixelPositionForScreenPosition(originalCursorPosition)
+  setPosition: ->
+    { left, top } = @editor.pixelPositionForScreenPosition(@originalCursorPosition)
 
     height = @outerHeight()
     potentialTop = top + @editor.lineHeight
-    potentialBottom = potentialTop - @editor.scrollTop()  + height
+    potentialBottom = potentialTop - @editor.scrollTop() + height
 
-    if potentialBottom > @editor.outerHeight()
+    if @aboveCursor or potentialBottom > @editor.outerHeight()
+      @aboveCursor = true
       @css(left: left, top: top - height, bottom: 'inherit')
     else
       @css(left: left, top: potentialTop, bottom: 'inherit')
 
-
   findMatchesForCurrentSelection: ->
     selection = @editor.getSelection()
     {prefix, suffix} = @prefixAndSuffixOfSelection(selection)
@@ -157,3 +160,8 @@ class Autocomplete extends SelectList
         suffix = match[0][suffixOffset..] if range.end.isGreaterThan(selectionRange.end)
 
     {prefix, suffix}
+
+  populateList: ->
+    super()
+
+    @setPosition()