Fix cursor result ranges for astal chars that get normalized to regul…

…ar ones

FIX: Fix a bug that caused `SearchCursor` to return invalid ranges when matching
astral chars that the the normalizer normalized to single-code-unit chars.

Closes codemirror/dev#1334

src/cursor.ts

@@ -76,7 +76,7 @@ export class SearchCursor implements Iterator<{from: number, to: number}>{
       let norm = this.normalize(str)
       for (let i = 0, pos = start;; i++) {
         let code = norm.charCodeAt(i)
-        let match = this.match(code, pos)
+        let match = this.match(code, pos, this.bufferPos + this.bufferStart)
         if (i == norm.length - 1) {
           if (match) {
             this.value = match
@@ -89,13 +89,13 @@ export class SearchCursor implements Iterator<{from: number, to: number}>{
     }
   }
 
-  private match(code: number, pos: number) {
+  private match(code: number, pos: number, end: number) {
     let match: null | {from: number, to: number} = null
     for (let i = 0; i < this.matches.length; i += 2) {
       let index = this.matches[i], keep = false
       if (this.query.charCodeAt(index) == code) {
         if (index == this.query.length - 1) {
-          match = {from: this.matches[i + 1], to: pos + 1}
+          match = {from: this.matches[i + 1], to: end}
         } else {
           this.matches[i]++
           keep = true
@@ -108,7 +108,7 @@ export class SearchCursor implements Iterator<{from: number, to: number}>{
     }
     if (this.query.charCodeAt(0) == code) {
       if (this.query.length == 1)
-        match = {from: pos, to: pos + 1}
+        match = {from: pos, to: end}
       else
         this.matches.push(1, pos)
     }

test/test-cursor.ts

@@ -64,6 +64,10 @@ describe("SearchCursor", () => {
   it("will not match partial normalized content", () => {
     testMatches(new SearchCursor(Text.of(["´"]), " "), [])
   })
+
+  it("produces the correct range for astral chars that get normalized to non-astral", () => {
+    testMatches(new SearchCursor(Text.of(["𝜎"]), "𝜎"), [[0, 2]])
+  })
 })
 
 describe("RegExpCursor", () => {