🐛 be more specific with hex colour handling

lib/Providers/Qr/BaconQrCodeProvider.php

@@ -125,12 +125,19 @@ class BaconQrCodeProvider implements IQRCodeProvider
     {
         if (is_string($colour) && $colour[0] == '#') {
             $hexToRGB = function ($input) {
+                // ensure input no longer has a # for more predictable division
+                // PHP 8.1 does not like implicitly casting a float to an int
+                $input = trim($input, '#');
+
+                if (strlen($input) != 3 && strlen($input) != 6) {
+                    throw new \RuntimeException('Colour should be a 3 or 6 character value after the #');
+                }
+
                 // split the array into three chunks
-                $split = str_split(trim($input, '#'), strlen($input) / 3);
+                $split = str_split($input, strlen($input) / 3);
 
                 // cope with three character hex reference
-                // three characters plus a # = 4
-                if (strlen($input) == 4) {
+                if (strlen($input) == 3) {
                     array_walk($split, function (&$character) {
                         $character = str_repeat($character, 2);
                     });

testsDependency/BaconQRCodeTest.php

@@ -34,4 +34,20 @@ class BaconQRCodeTest extends TestCase
 
         new BaconQrCodeProvider(1, '#000', 'not-a-colour');
     }
+
+    public function testBadTextColourHexRef()
+    {
+        $this->expectException(\RuntimeException::class);
+
+        new BaconQrCodeProvider(1, '#AAAA', '#FFF');
+    }
+
+    public function testBadBackgroundColourHexRef()
+    {
+        $this->expectException(\RuntimeException::class);
+
+        new BaconQrCodeProvider(1, '#000', '#AAAA');
+    }
+
+
 }