Make sure coordsChar doesn't return positions in collapsed spans

Closes #5392

Author: marijnh

src/line/spans.js

@@ -218,6 +218,16 @@ function collapsedSpanAtSide(line, start) {
 export function collapsedSpanAtStart(line) { return collapsedSpanAtSide(line, true) }
 export function collapsedSpanAtEnd(line) { return collapsedSpanAtSide(line, false) }
 
+export function collapsedSpanAround(line, ch) {
+  let sps = sawCollapsedSpans && line.markedSpans, found
+  if (sps) for (let i = 0; i < sps.length; ++i) {
+    let sp = sps[i]
+    if (sp.marker.collapsed && (sp.from == null || sp.from < ch) && (sp.to == null || sp.to > ch) &&
+        (!found || compareCollapsedMarkers(found, sp.marker) < 0)) found = sp.marker
+  }
+  return found
+}
+
 // Test whether there exists a collapsed span that partially
 // overlaps (covers the start or end, but not both) of a new span.
 // Such overlap is not allowed.

src/measurement/position_measurement.js

@@ -1,6 +1,6 @@
 import { buildLineContent, LineView } from "../line/line_data.js"
 import { clipPos, Pos } from "../line/pos.js"
-import { collapsedSpanAtEnd, heightAtLine, lineIsHidden, visualLine } from "../line/spans.js"
+import { collapsedSpanAround, heightAtLine, lineIsHidden, visualLine } from "../line/spans.js"
 import { getLine, lineAtHeight, lineNo, updateLineHeight } from "../line/utils_line.js"
 import { bidiOther, getBidiPartAt, getOrder } from "../util/bidi.js"
 import { chrome, android, ie, ie_version } from "../util/browser.js"
@@ -430,12 +430,11 @@ export function coordsChar(cm, x, y) {
   let lineObj = getLine(doc, lineN)
   for (;;) {
     let found = coordsCharInner(cm, lineObj, lineN, x, y)
-    let merged = collapsedSpanAtEnd(lineObj)
-    let mergedPos = merged && merged.find(0, true)
-    if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
-      lineN = lineNo(lineObj = mergedPos.to.line)
-    else
-      return found
+    let collapsed = collapsedSpanAround(lineObj, found.ch + (found.xRel > 0 ? 1 : 0))
+    if (!collapsed) return found
+    let rangeEnd = collapsed.find(1)
+    if (rangeEnd.line == lineN) return rangeEnd
+    lineObj = getLine(doc, lineN = rangeEnd.line)
   }
 }
 

test/test.js

@@ -889,6 +889,15 @@ testCM("hiddenLinesSelectAll", function(cm) {  // Issue #484
   eqCursorPos(cm.getCursor(false), Pos(10, 4));
 });
 
+testCM("clickFold", function(cm) { // Issue #5392
+  cm.setValue("foo { bar }")
+  var widget = document.createElement("span")
+  widget.textContent = "<>"
+  cm.markText(Pos(0, 5), Pos(0, 10), {replacedWith: widget})
+  var after = cm.charCoords(Pos(0, 10))
+  var foundOn = cm.coordsChar({left: after.left - 1, top: after.top + 4})
+  is(foundOn.ch <= 5 || foundOn.ch >= 10, "Position is not inside the folded range")
+})
 
 testCM("everythingFolded", function(cm) {
   addDoc(cm, 2, 2);