From 314528801bba4885b75b1d4476d5be57b9975c80 Mon Sep 17 00:00:00 2001
From: Shish <shish@shishnet.org>
Date: Tue, 27 Jun 2023 15:42:42 +0100
Subject: [PATCH] make clamp() more robust

---
 core/polyfills.php            |  8 ++------
 core/tests/polyfills.test.php | 13 ++++++++-----
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/core/polyfills.php b/core/polyfills.php
index 437b25ed..1b6b9cfc 100644
--- a/core/polyfills.php
+++ b/core/polyfills.php
@@ -228,10 +228,6 @@ if (!function_exists('http_parse_headers')) {
  */
 function find_header(array $headers, string $name): ?string
 {
-    if (!is_array($headers)) {
-        return null;
-    }
-
     $header = null;
 
     if (array_key_exists($name, $headers)) {
@@ -457,9 +453,9 @@ function page_number(string $input, ?int $max=null): int
     return $pageNumber;
 }
 
-function clamp(?int $val, ?int $min=null, ?int $max=null): int
+function clamp(int $val, ?int $min=null, ?int $max=null): int
 {
-    if (!is_numeric($val) || (!is_null($min) && $val < $min)) {
+    if (!is_null($min) && $val < $min) {
         $val = $min;
     }
     if (!is_null($max) && $val > $max) {
diff --git a/core/tests/polyfills.test.php b/core/tests/polyfills.test.php
index edae790a..a196da3b 100644
--- a/core/tests/polyfills.test.php
+++ b/core/tests/polyfills.test.php
@@ -73,11 +73,14 @@ class PolyfillsTest extends TestCase
 
     public function test_clamp()
     {
-        $this->assertEquals(5, clamp(0, 5, 10));
-        $this->assertEquals(5, clamp(5, 5, 10));
-        $this->assertEquals(7, clamp(7, 5, 10));
-        $this->assertEquals(10, clamp(10, 5, 10));
-        $this->assertEquals(10, clamp(15, 5, 10));
+        $this->assertEquals(5, clamp(0, 5, 10)); // too small
+        $this->assertEquals(5, clamp(5, 5, 10)); // lower limit
+        $this->assertEquals(7, clamp(7, 5, 10)); // ok
+        $this->assertEquals(10, clamp(10, 5, 10)); // upper limit
+        $this->assertEquals(10, clamp(15, 5, 10)); // too large
+        $this->assertEquals(0, clamp(0, null, 10)); // no lower limit
+        $this->assertEquals(10, clamp(10, 0, null)); // no upper limit
+        $this->assertEquals(42, clamp(42, null, null)); // no limit
     }
 
     public function test_truncate()