From adbc14e60ab6f8a3a3b1b644f1fd0583ba3b31a4 Mon Sep 17 00:00:00 2001
From: Ori Riner <OriR@users.noreply.github.com>
Date: Sat, 31 Mar 2018 12:14:10 +0300
Subject: [PATCH] Add autofix for double-slash-comment-empty-line-before (#230)

* Add autofix

* Address PR comments
---
 .../__tests__/index.js                        | 40 ++++++++++++++++++-
 .../index.js                                  | 24 ++++++++++-
 2 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/src/rules/double-slash-comment-empty-line-before/__tests__/index.js b/src/rules/double-slash-comment-empty-line-before/__tests__/index.js
index dd0f4fb9..d9b24fa5 100644
--- a/src/rules/double-slash-comment-empty-line-before/__tests__/index.js
+++ b/src/rules/double-slash-comment-empty-line-before/__tests__/index.js
@@ -53,18 +53,30 @@ const alwaysGeneralTests = {
     {
       code: `
       // comment 1
+      // comment 2
+    `,
+      fixed: `
+      // comment 1
+
       // comment 2
     `,
       message: messages.expected
     },
     {
       code: "// comment\r\n// comment",
+      fixed: "// comment\r\n\r\n// comment",
       description: "One windows newline between comments.",
       message: messages.expected
     },
     {
       code: `
       a { color: pink;
+      // comment w/o empty line
+      top: 0; }
+    `,
+      fixed: `
+      a { color: pink;
+
       // comment w/o empty line
       top: 0; }
     `,
@@ -73,6 +85,8 @@ const alwaysGeneralTests = {
     {
       code:
         "a { color: pink;\r\n// comment w/o empty lines, Win style\r\ntop: 0; }",
+      fixed:
+        "a { color: pink;\r\n\r\n// comment w/o empty lines, Win style\r\ntop: 0; }",
       description: "One Windows newline before comment.",
       message: messages.expected
     }
@@ -88,6 +102,7 @@ testRule(rule, {
   config: ["always"],
   syntax: "scss",
   skipBasicChecks: true,
+  fix: true,
 
   accept: alwaysGeneralTests.accept.concat([
     {
@@ -103,6 +118,11 @@ testRule(rule, {
   reject: alwaysGeneralTests.reject.concat([
     {
       code: `a {
+      // First-nested, no empty line before.
+      color: pink;
+    }`,
+      fixed: `a {
+
       // First-nested, no empty line before.
       color: pink;
     }`,
@@ -119,16 +139,17 @@ testRule(rule, {
   config: ["always", { except: ["first-nested"] }],
   syntax: "scss",
   skipBasicChecks: true,
+  fix: true,
 
   accept: alwaysGeneralTests.accept.concat([
     {
       code: `
       a {
-        // First nested, now empty line.
+        // First nested, no empty line.
         color: pink;
       }
     `,
-      description: "First nested, now empty line."
+      description: "First nested, no empty line."
     }
   ]),
 
@@ -137,6 +158,11 @@ testRule(rule, {
       code: `
       a {
 
+      // First-nested, with empty line (rejected).
+      color: pink;
+    }`,
+      fixed: `
+      a {
       // First-nested, with empty line (rejected).
       color: pink;
     }`,
@@ -174,6 +200,7 @@ testRule(rule, {
   config: ["always", { ignore: ["between-comments"] }],
   syntax: "scss",
   skipBasicChecks: true,
+  fix: true,
 
   accept: [
     {
@@ -230,6 +257,15 @@ testRule(rule, {
         top: 0;
       }
     `,
+      fixed: `
+      a {
+        color: pink;
+
+        /// comment
+        /// comment
+        top: 0;
+      }
+    `,
       description: "Multiple comments, inside ruleset, no empty lines.",
       message: messages.expected
     }
diff --git a/src/rules/double-slash-comment-empty-line-before/index.js b/src/rules/double-slash-comment-empty-line-before/index.js
index f003c585..099697e9 100644
--- a/src/rules/double-slash-comment-empty-line-before/index.js
+++ b/src/rules/double-slash-comment-empty-line-before/index.js
@@ -15,7 +15,7 @@ export const messages = utils.ruleMessages(ruleName, {
 
 const stylelintCommandPrefix = "stylelint-";
 
-export default function(expectation, options) {
+export default function(expectation, options, context) {
   return (root, result) => {
     const validOptions = utils.validateOptions(
       result,
@@ -37,6 +37,17 @@ export default function(expectation, options) {
       return;
     }
 
+    const fix = (comment, match, replace) => {
+      const escapedMatch = match.replace(
+        /(\r)?\n/g,
+        (_, r) => (r ? "\\r\\n" : "\\n")
+      );
+      comment.raws.before = comment.raws.before.replace(
+        new RegExp(`^${escapedMatch}`),
+        replace
+      );
+    };
+
     root.walkComments(comment => {
       // Only process // comments
       if (!comment.raws.inline && !comment.inline) {
@@ -90,6 +101,17 @@ export default function(expectation, options) {
         return;
       }
 
+      if (context.fix) {
+        if (expectEmptyLineBefore && !hasEmptyLineBefore) {
+          fix(comment, context.newline, context.newline + context.newline);
+          return;
+        }
+        if (!expectEmptyLineBefore && hasEmptyLineBefore) {
+          fix(comment, context.newline + context.newline, context.newline);
+          return;
+        }
+      }
+
       const message = expectEmptyLineBefore
         ? messages.expected
         : messages.rejected;