From 0bd73b436373fe1b623a73f374c5259c86c9d3c8 Mon Sep 17 00:00:00 2001
From: pfg <pfg@pfg.pw>
Date: Fri, 25 Jul 2025 22:22:04 -0700
Subject: [PATCH] Fix toIncludeRepeated (#21366)

Fixes #12276: toIncludeRepeated should check for the exact repeat count
not >=

This is a breaking change because some people may be relying on the
existing behaviour. Should it be feature-flagged for 1.3?

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
---
 src/bun.js/test/expect.zig                |  6 ++---
 test/js/bun/test/jest-extended.test.js    |  6 ++---
 test/regression/issue/issue-12276.test.ts | 27 +++++++++++++++++++++++
 3 files changed, 32 insertions(+), 7 deletions(-)
 create mode 100644 test/regression/issue/issue-12276.test.ts

diff --git a/src/bun.js/test/expect.zig b/src/bun.js/test/expect.zig
index 7fdbaa504e..735e42f2c4 100644
--- a/src/bun.js/test/expect.zig
+++ b/src/bun.js/test/expect.zig
@@ -3841,10 +3841,8 @@ pub const Expect = struct {
             return globalThis.throw("toIncludeRepeated() requires the first argument to be a non-empty string", .{});
         }
 
-        if (countAsNum == 0)
-            pass = !strings.contains(expectStringAsStr, subStringAsStr)
-        else
-            pass = std.mem.containsAtLeast(u8, expectStringAsStr, countAsNum, subStringAsStr);
+        const actual_count = std.mem.count(u8, expectStringAsStr, subStringAsStr);
+        pass = actual_count == countAsNum;
 
         if (not) pass = !pass;
         if (pass) return .js_undefined;
diff --git a/test/js/bun/test/jest-extended.test.js b/test/js/bun/test/jest-extended.test.js
index 7602122aaa..4cf2a29e7a 100644
--- a/test/js/bun/test/jest-extended.test.js
+++ b/test/js/bun/test/jest-extended.test.js
@@ -601,13 +601,13 @@ describe("jest-extended", () => {
     expect("abc").not.toIncludeRepeated("d", 1);
 
     // Any other number
-    expect("abc abc abc").toIncludeRepeated("abc", 1);
-    expect("abc abc abc").toIncludeRepeated("abc", 2);
+    expect("abc abc abc").not.toIncludeRepeated("abc", 1);
+    expect("abc abc abc").not.toIncludeRepeated("abc", 2);
     expect("abc abc abc").toIncludeRepeated("abc", 3);
     expect("abc abc abc").not.toIncludeRepeated("abc", 4);
 
     // Emojis/Unicode
-    expect("😘🥳😤😘🥳").toIncludeRepeated("😘", 1);
+    expect("😘🥳😤😘🥳").toIncludeRepeated("😘", 2);
     expect("😘🥳😤😘🥳").toIncludeRepeated("🥳", 2);
     expect("😘🥳😤😘🥳").not.toIncludeRepeated("😘", 3);
     expect("😘🥳😤😘🥳").not.toIncludeRepeated("😶‍🌫️", 1);
diff --git a/test/regression/issue/issue-12276.test.ts b/test/regression/issue/issue-12276.test.ts
new file mode 100644
index 0000000000..781a255383
--- /dev/null
+++ b/test/regression/issue/issue-12276.test.ts
@@ -0,0 +1,27 @@
+import { expect, test } from "bun:test";
+
+// https://github.com/oven-sh/bun/issues/12276
+test("toIncludeRepeated should check for exact count, not at least count", () => {
+  // The bug: toIncludeRepeated was checking if string contains AT LEAST n occurrences
+  // Instead of EXACTLY n occurrences
+
+  // These should pass - exact match
+  expect("hello hello world").toIncludeRepeated("hello", 2);
+  expect("hello world").toIncludeRepeated("hello", 1);
+  expect("world").toIncludeRepeated("hello", 0);
+
+  // These should pass - not exact match with .not
+  expect("hello hello world").not.toIncludeRepeated("hello", 1);
+  expect("hello hello world").not.toIncludeRepeated("hello", 3);
+  expect("hello hello hello").not.toIncludeRepeated("hello", 2);
+
+  // Additional test cases
+  expect("abc abc abc").toIncludeRepeated("abc", 3);
+  expect("abc abc abc").not.toIncludeRepeated("abc", 1);
+  expect("abc abc abc").not.toIncludeRepeated("abc", 2);
+  expect("abc abc abc").not.toIncludeRepeated("abc", 4);
+
+  // Edge cases - std.mem.count doesn't count overlapping occurrences
+  expect("aaa").toIncludeRepeated("aa", 1); // "aa" appears once (non-overlapping)
+  expect("aaaa").toIncludeRepeated("aa", 2); // "aa" appears twice (non-overlapping)
+});