Fix: no-unused-disable crashes

Author: mysticatea

lib/patch.js

@@ -41,26 +41,31 @@ function getSeverity(config, ruleId) {
  * @returns {Comment|undefined} The gotten comment.
  */
 function getCommentAt(message, sourceCode) {
-    if (sourceCode == null) {
-        return undefined
+    if (sourceCode != null) {
+        const loc = { line: message.line, column: message.column - 1 }
+        const index = sourceCode.getIndexFromLoc(loc)
+        const options = { includeComments: true }
+        const comment = sourceCode.getTokenByRangeStart(index, options)
+        if (
+            comment != null &&
+            (comment.type === "Line" || comment.type === "Block")
+        ) {
+            return comment
+        }
     }
-
-    const index = sourceCode.getIndexFromLoc(message) - 1
-    return sourceCode.getTokenByRangeStart(index, { includeComments: true })
+    return undefined
 }
 
 /**
  * Check whether a given message is a `reportUnusedDisableDirectives` error.
  * @param {Message} message The message.
- * @param {Comment|undefined} comment The comment which existed at the message location.
  * @returns {boolean} `true` if the message is a `reportUnusedDisableDirectives` error.
  */
-function isUnusedDisableDirectiveError(message, comment) {
+function isUnusedDisableDirectiveError(message) {
     return (
         !message.fatal &&
         !message.ruleId &&
-        message.message.includes("eslint-disable") &&
-        (comment == null || comment.type === "Block" || comment.type === "Line")
+        message.message.includes("eslint-disable")
     )
 }
 
@@ -111,17 +116,15 @@ function createNoUnusedDisableError(ruleId, severity, message, comment) {
 function convert(messages, sourceCode, ruleId, severity, keepAsIs) {
     for (let i = messages.length - 1; i >= 0; --i) {
         const message = messages[i]
-        const comment = getCommentAt(message, sourceCode)
-
-        if (!isUnusedDisableDirectiveError(message, comment)) {
+        if (!isUnusedDisableDirectiveError(message)) {
             continue
         }
 
         const newMessage = createNoUnusedDisableError(
             ruleId,
             severity,
             message,
-            comment
+            getCommentAt(message, sourceCode)
         )
 
         if (keepAsIs) {