From 5c37ecf3f5c92b75d24c15dc8c02a93f82a2a518 Mon Sep 17 00:00:00 2001
From: Wylie Conlon <wylie@superblockshq.com>
Date: Fri, 14 Jun 2024 17:00:34 -0400
Subject: [PATCH] fix formatting of block quotes with **/ closing characters

---
 src/lexer/NestedComment.ts | 34 ++++++++++++++++++++--------------
 test/features/comments.ts  |  6 ++++++
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/lexer/NestedComment.ts b/src/lexer/NestedComment.ts
index 983f0e3f28..4db128f329 100644
--- a/src/lexer/NestedComment.ts
+++ b/src/lexer/NestedComment.ts
@@ -2,8 +2,6 @@
 import { RegExpLike } from './TokenizerEngine.js';
 
 const START = /\/\*/uy; // matches: /*
-const MIDDLE = /([^/*]|\*[^/]|\/[^*])+/uy; // matches text NOT containing /* or */
-const END = /\*\//uy; // matches: */
 
 /**
  * An object mimicking a regular expression,
@@ -15,29 +13,37 @@ export class NestedComment implements RegExpLike {
   public exec(input: string): string[] | null {
     let result = '';
     let match: string | null;
-    let nestLevel = 0;
 
     if ((match = this.matchSection(START, input))) {
       result += match;
-      nestLevel++;
     } else {
       return null;
     }
 
-    while (nestLevel > 0) {
-      if ((match = this.matchSection(START, input))) {
-        result += match;
-        nestLevel++;
-      } else if ((match = this.matchSection(END, input))) {
-        result += match;
+    let nestLevel = 1;
+    // start at the last index, break if we find a closing */ that matches
+    for (let i = this.lastIndex; i < input.length; i++) {
+      if (input[i] === '*' && input[i + 1] === '/') {
         nestLevel--;
-      } else if ((match = this.matchSection(MIDDLE, input))) {
-        result += match;
+        result += '*/';
+        i++;
+        if (nestLevel === 0) {
+          this.lastIndex = i;
+          return [result];
+        } else if (nestLevel < 0) {
+          return null;
+        }
+      } else if (input[i] === '/' && input[i + 1] === '*') {
+        nestLevel++;
+        result += '/*';
+        i++;
       } else {
-        return null;
+        result += input[i];
       }
     }
-
+    if (nestLevel > 0) {
+      return null;
+    }
     return [result];
   }
 
diff --git a/test/features/comments.ts b/test/features/comments.ts
index 47b51ac957..4394123cbf 100644
--- a/test/features/comments.ts
+++ b/test/features/comments.ts
@@ -239,6 +239,12 @@ export default function supportsComments(format: FormatFn, opts: CommentsConfig
     `);
   });
 
+  // Regression test for https://github.com/sql-formatter-org/sql-formatter/issues/747
+  it('handles block comments with /** and **/ patterns', () => {
+    const sql = `/** This is a block comment **/`;
+    expect(format(sql)).toBe(sql);
+  });
+
   if (opts.hashComments) {
     it('supports # line comment', () => {
       const result = format('SELECT alpha # commment\nFROM beta');