From c3f74e3524b5d5acc3e78646946552d15747dbcd Mon Sep 17 00:00:00 2001
From: Daniel Shafer <github@danielshafer.com>
Date: Fri, 23 Oct 2026 16:05:49 +0000
Subject: [PATCH] fix(path): accept readonly array in common()

---
 path/_common/common.ts |  2 +-
 path/common.ts         |  2 +-
 path/common_test.ts    | 20 ++++++++++++++++++++
 path/posix/common.ts   |  2 +-
 path/windows/common.ts |  2 +-
 5 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/path/_common/common.ts b/path/_common/common.ts
index 9ff1619ca04e..940d79455d71 100644
--- a/path/_common/common.ts
+++ b/path/_common/common.ts
@@ -1,7 +1,7 @@
 // Copyright 2018-2026 the Deno authors. MIT license.
 // This module is browser compatible.
 
-export function common(paths: string[], sep: string): string {
+export function common(paths: readonly string[], sep: string): string {
   const [first = "", ...remaining] = paths;
   const parts = first.split(sep);
 
diff --git a/path/common.ts b/path/common.ts
index 36c9d678cf6e..4e56b60c499d 100644
--- a/path/common.ts
+++ b/path/common.ts
@@ -30,6 +30,6 @@ import { SEPARATOR } from "./constants.ts";
  * }
  * ```
  */
-export function common(paths: string[]): string {
+export function common(paths: readonly string[]): string {
   return _common(paths, SEPARATOR);
 }
diff --git a/path/common_test.ts b/path/common_test.ts
index db18ec809be6..04a4b9be3a36 100644
--- a/path/common_test.ts
+++ b/path/common_test.ts
@@ -96,3 +96,23 @@ Deno.test({
     assertEquals(actual, "file://deno/");
   },
 });
+
+Deno.test({
+  name: "common() accepts readonly arrays",
+  fn() {
+    const posixPaths: readonly string[] = [
+      "./deno/std/path/mod.ts",
+      "./deno/std/fs/mod.ts",
+    ];
+    assertEquals(posix.common(posixPaths), "./deno/std/");
+
+    const windowsPaths: readonly string[] = [
+      "C:\\deno\\std\\path\\mod.ts",
+      "C:\\deno\\std\\fs\\mod.ts",
+    ];
+    assertEquals(windows.common(windowsPaths), "C:\\deno\\std\\");
+
+    const paths = ["./deno/std/path/mod.ts", "./deno/std/path/mod.ts"] as const;
+    assertEquals(common(paths), "./deno/std/path/mod.ts");
+  },
+});
diff --git a/path/posix/common.ts b/path/posix/common.ts
index 61255fa7908b..ca20ea3f538d 100644
--- a/path/posix/common.ts
+++ b/path/posix/common.ts
@@ -21,6 +21,6 @@ import { SEPARATOR } from "./constants.ts";
  * @param paths The paths to compare.
  * @returns The common path.
  */
-export function common(paths: string[]): string {
+export function common(paths: readonly string[]): string {
   return _common(paths, SEPARATOR);
 }
diff --git a/path/windows/common.ts b/path/windows/common.ts
index 393893bf8543..13475e13996b 100644
--- a/path/windows/common.ts
+++ b/path/windows/common.ts
@@ -22,6 +22,6 @@ import { SEPARATOR } from "./constants.ts";
  * @param paths The paths to compare.
  * @returns The common path.
  */
-export function common(paths: string[]): string {
+export function common(paths: readonly string[]): string {
   return _common(paths, SEPARATOR);
 }