Properly track associativity for shift-click selections

FIX: Make sure the selection head associativity is properly set for mouse
selections made with shift held down.

Author: marijnh

package.json

@@ -26,7 +26,7 @@
   "sideEffects": false,
   "license": "MIT",
   "dependencies": {
-    "@codemirror/state": "^6.5.0",
+    "@codemirror/state": "^6.6.0",
     "crelt": "^1.0.6",
     "style-mod": "^4.1.0",
     "w3c-keyname": "^2.2.4"

src/docview.ts

@@ -525,7 +525,7 @@ export class DocView {
     }
 
     let {range} = target
-    let rect = this.coordsAt(range.head, range.empty ? range.assoc : range.head > range.anchor ? -1 : 1), other
+    let rect = this.coordsAt(range.head, range.assoc ?? (range.empty ? 0 : range.head > range.anchor ? -1 : 1)), other
     if (!rect) return
     if (!range.empty && (other = this.coordsAt(range.anchor, range.anchor > range.head ? -1 : 1)))
       rect = {left: Math.min(rect.left, other.left), top: Math.min(rect.top, other.top),

src/draw-selection.ts

@@ -76,7 +76,7 @@ const cursorLayer = layer({
       let prim = r == state.selection.main
       if (r.empty || conf.drawRangeCursor && !(prim && browser.ios && conf.iosSelectionHandles)) {
         let className = prim ? "cm-cursor cm-cursor-primary" : "cm-cursor cm-cursor-secondary"
-        let cursor = r.empty ? r : EditorSelection.cursor(r.head, r.head > r.anchor ? -1 : 1)
+        let cursor = r.empty ? r : EditorSelection.cursor(r.head, r.assoc)
         for (let piece of RectangleMarker.forRange(view, className, cursor)) cursors.push(piece)
       }
     }

src/input.ts

@@ -591,10 +591,10 @@ function basicMouseSelection(view: EditorView, event: MouseEvent) {
       if (start.pos != cur.pos && !extend) {
         let startRange = rangeForClick(view, start.pos, start.assoc, type)
         let from = Math.min(startRange.from, range.from), to = Math.max(startRange.to, range.to)
-        range = from < range.from ? EditorSelection.range(from, to) : EditorSelection.range(to, from)
+        range = from < range.from ? EditorSelection.range(from, to, range.assoc) : EditorSelection.range(to, from, range.assoc)
       }
       if (extend)
-        return startSel.replaceRange(startSel.main.extend(range.from, range.to))
+        return startSel.replaceRange(startSel.main.extend(range.from, range.to, range.assoc))
       else if (multiple && type == 1 && startSel.ranges.length > 1 && (removed = removeRangeAround(startSel, cur.pos)))
         return removed
       else if (multiple)