Fix: false positive on rulelines-between-class-members (fixes #9665) (#9680)

* Fix: `lines-between-class-memebers` (fixes #9665)

`lines-between-class-memebers` if a comment occurs between class members

* Add tests suggested by reviewers.

* Add comments

* Refactor: remove a nest.

* Refactor: declare variables just before they are needed.

Author: sakabar

lib/rules/lines-between-class-members.js

@@ -55,7 +55,56 @@ module.exports = {
          * @returns {boolean} True if there is at least a line between the tokens
          */
         function isPaddingBetweenTokens(first, second) {
-            return second.loc.start.line - first.loc.end.line >= 2;
+            const comments = sourceCode.getCommentsBefore(second);
+            const len = comments.length;
+
+            // If there is no comments
+            if (len === 0) {
+                const linesBetweenFstAndSnd = second.loc.start.line - first.loc.end.line - 1;
+
+                return linesBetweenFstAndSnd >= 1;
+            }
+
+
+            // If there are comments
+            let sumOfCommentLines = 0; // the numbers of lines of comments
+            let prevCommentLineNum = -1; // line number of the end of the previous comment
+
+            for (let i = 0; i < len; i++) {
+                const commentLinesOfThisComment = comments[i].loc.end.line - comments[i].loc.start.line + 1;
+
+                sumOfCommentLines += commentLinesOfThisComment;
+
+                /*
+                 * If this comment and the previous comment are in the same line,
+                 * the count of comment lines is duplicated. So decrement sumOfCommentLines.
+                 */
+                if (prevCommentLineNum === comments[i].loc.start.line) {
+                    sumOfCommentLines -= 1;
+                }
+
+                prevCommentLineNum = comments[i].loc.end.line;
+            }
+
+            /*
+             * If the first block and the first comment are in the same line,
+             * the count of comment lines is duplicated. So decrement sumOfCommentLines.
+             */
+            if (first.loc.end.line === comments[0].loc.start.line) {
+                sumOfCommentLines -= 1;
+            }
+
+            /*
+             * If the last comment and the second block are in the same line,
+             * the count of comment lines is duplicated. So decrement sumOfCommentLines.
+             */
+            if (comments[len - 1].loc.end.line === second.loc.start.line) {
+                sumOfCommentLines -= 1;
+            }
+
+            const linesBetweenFstAndSnd = second.loc.start.line - first.loc.end.line - 1;
+
+            return linesBetweenFstAndSnd - sumOfCommentLines >= 1;
         }
 
         return {
@@ -65,8 +114,7 @@ module.exports = {
                 for (let i = 0; i < body.length - 1; i++) {
                     const curFirst = sourceCode.getFirstToken(body[i]);
                     const curLast = sourceCode.getLastToken(body[i]);
-                    const comments = sourceCode.getCommentsBefore(body[i + 1]);
-                    const nextFirst = comments.length ? comments[0] : sourceCode.getFirstToken(body[i + 1]);
+                    const nextFirst = sourceCode.getFirstToken(body[i + 1]);
                     const isPadded = isPaddingBetweenTokens(curLast, nextFirst);
                     const isMulti = !astUtils.isTokenOnSameLine(curFirst, curLast);
                     const skip = !isMulti && options[1].exceptAfterSingleLine;

tests/lib/rules/lines-between-class-members.js

@@ -36,13 +36,20 @@ ruleTester.run("lines-between-class-members", rule, {
         "class foo{ bar(){}\n\nbaz(){}}",
         "class foo{ bar(){}\n\n/*comments*/baz(){}}",
         "class foo{ bar(){}\n\n//comments\nbaz(){}}",
+        "class foo{ bar(){}\n//comments\n\nbaz(){}}",
+        "class A{ foo() {} // a comment\n\nbar() {}}",
+        "class A{ foo() {}\n/* a */ /* b */\n\nbar() {}}",
+        "class A{ foo() {}/* a */ \n\n /* b */bar() {}}",
 
         "class foo{ bar(){}\n\n;;baz(){}}",
         "class foo{ bar(){};\n\nbaz(){}}",
 
         { code: "class foo{ bar(){}\nbaz(){}}", options: ["never"] },
         { code: "class foo{ bar(){}\n/*comments*/baz(){}}", options: ["never"] },
         { code: "class foo{ bar(){}\n//comments\nbaz(){}}", options: ["never"] },
+        { code: "class foo{ bar(){}/* comments\n\n*/baz(){}}", options: ["never"] },
+        { code: "class foo{ bar(){}/* \ncomments\n*/baz(){}}", options: ["never"] },
+        { code: "class foo{ bar(){}\n/* \ncomments\n*/\nbaz(){}}", options: ["never"] },
 
         { code: "class foo{ bar(){}\n\nbaz(){}}", options: ["always"] },
         { code: "class foo{ bar(){}\n\n/*comments*/baz(){}}", options: ["always"] },