[Fix] jsx-props-no-multi-spaces: fix a false positive for beside comments

CHANGELOG.md

@@ -20,8 +20,10 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 * [`jsx-max-depth`]: avoid crash with childless jsx child ([#2869][] @ljharb, @AriPerkkio)
 * [`no-unknown-property`]: avoid crash with prop named with Object.prototype key ([#2879][] @ljharb, @AriPerkkio)
 * [`prop-types`]: default argument does not count as props-types declaration ([#2877][] @golopot)
+* [`jsx-props-no-multi-spaces`]: fix a false positive for beside comments ([#2878][] @golopot)
 
 [#2879]: https://github.com/yannickcr/eslint-plugin-react/issues/2879
+[#2878]: https://github.com/yannickcr/eslint-plugin-react/pull/2878
 [#2877]: https://github.com/yannickcr/eslint-plugin-react/pull/2877
 [#2875]: https://github.com/yannickcr/eslint-plugin-react/issues/2875
 [#2871]: https://github.com/yannickcr/eslint-plugin-react/issues/2871

lib/rules/jsx-props-no-multi-spaces.js

@@ -39,30 +39,24 @@ module.exports = {
       }
     }
 
-    function hasEmptyLines(node, leadingLineCount) {
-      const allComments = sourceCode.getCommentsBefore(node);
-      let commentLines = 0;
-
-      if (allComments.length > 0) {
-        allComments.forEach((comment) => {
-          const start = comment.loc.start.line;
-          const end = comment.loc.end.line;
-
-          commentLines += (end - start + 1);
-        });
-
-        return commentLines !== leadingLineCount;
+    // First and second must be adjacent nodes
+    function hasEmptyLines(first, second) {
+      const comments = sourceCode.getCommentsBefore(second);
+      const nodes = [].concat(first, comments, second);
+
+      for (let i = 1; i < nodes.length; i += 1) {
+        const prev = nodes[i - 1];
+        const curr = nodes[i];
+        if (curr.loc.start.line - prev.loc.end.line >= 2) {
+          return true;
+        }
       }
 
-      return true;
+      return false;
     }
 
     function checkSpacing(prev, node) {
-      const prevNodeEndLine = prev.loc.end.line;
-      const currNodeStartLine = node.loc.start.line;
-      const leadingLineCount = currNodeStartLine - prevNodeEndLine - 1;
-
-      if (leadingLineCount > 0 && hasEmptyLines(node, leadingLineCount)) {
+      if (hasEmptyLines(prev, node)) {
         context.report({
           node,
           message: `Expected no line gap between “${getPropName(prev)}” and “${getPropName(node)}”`

tests/lib/rules/jsx-props-no-multi-spaces.js

@@ -108,6 +108,14 @@ ruleTester.run('jsx-props-no-multi-spaces', rule, {
        type="button"
      />
    `
+  }, {
+    code: `
+     <App
+       foo="Some button" // comment
+       // comment
+       bar=""
+     />
+   `
   }, {
     code: `
      <button