Some minor improvements

* Rename method `normalizeArrays` to `fixDuplicateKeysInString` to be
  more specific.
* `strstr` to `str_contains`.
* If preg_replace should somehow fail, keep the $query (also phpstan
  complained).
* Move test case to the FromStringTest file.
* Add changelog.

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.0.2] - 2023-04-12
+### Fixed
+- Duplicate keys without array notation (like `foo=bar&foo=baz`) are now also interpreted as array (like `foo[]=bar&foo[]=baz`). This is considered a bugfix because:
+  - Previously `foo=bar&foo=baz` became `foo=baz`, which is most likely unwanted behavior.
+  - Of course, such query strings should preferably be written using the array notation (`[]`), but if such a query is written without the brackets, the intention is either that it should be an array, or it's a mistake. If it is a mistake, the probability to notice it is higher, when the result contains all values instead of only the last one.
+  - As this library is also part of the crwlr crawling library and there are servers intentionally using the syntax without brackets (e.g. google https://fonts.googleapis.com/css2?family=Baloo&family=Roboto) it's better to interpret it as an array.
+
 ## [1.0.1] - 2023-01-30
 ### Fixed
 - When creating a `Query` from string, and it contains empty key value parts, like `&foo=bar`, `foo=bar&` or `foo=bar&&baz=quz`, the unnecessary `&` characters are removed in the string version now. For example, `&foo=bar` previously lead to `$instance->toString()` returning `&foo=bar` and now it returns `foo=bar`.

src/Query.php

@@ -555,8 +555,8 @@ private function sanitize(string $query): string
         }
 
         $query = preg_replace('/&+/', '&', $query) ?? $query;
-        
-        $query = $this->normalizeArrays($query);
+
+        $query = $this->fixDuplicateKeysInString($query);
 
         return $this->arrayToString($this->stringToArray($query));
     }
@@ -1004,26 +1004,28 @@ private function spaceCharacter(): string
     }
 
     /**
+     * Fix duplicate keys in query strings without brackets
+     *
      * Arrays can be present in query strings in two formats, as follows:
      *  1.) ?key[]=value1&key[]=value2
      *  2.) ?key=value1&key=value2
      *
      * Both *should* be parsed in the same way, however, PHP's parse_str() doesn't handle version #1. This function
      * normalizes version #2 structure query strings to #1 so that we can parse both accordingly.
      */
-    private function normalizeArrays(string $query): string
+    private function fixDuplicateKeysInString(string $query): string
     {
         // Count the occurrences of all request keys to check for duplicates
         $keyOccurrences = array_count_values(array_map(fn ($val) => explode('=', $val, 2)[0], explode('&', $query)));
 
         foreach ($keyOccurrences as $key => $count) {
-            if ($count > 1 && !strstr($key, '[')) {
+            if ($count > 1 && !str_contains($key, '[')) {
                 // Duplicate query string key without array notation, convert to {keyName}[] structure
                 $query = preg_replace(
                     '#(^|[?&])(' . preg_quote($key) . ')=#',
                     '$1$2[]=',
                     $query,
-                );
+                ) ?? $query;
             }
         }
 

tests/FromStringTest.php

@@ -178,3 +178,11 @@ function (array $array, string $normalized, string $raw) {
         'foo.bar[0]=v1&foo.bar_extra[0]=v2&foo.bar.extra[0]=v3',
     ],
 ]);
+
+test('Duplicate query string keys are converted to arrays', function () {
+    expect(Query::fromString('test=1&test2=2&test=2&test[]=3&test[test]=4')->toArray())
+        ->toEqual([
+            'test' => [1, 2, 3, 'test' => 4],
+            'test2' => 2,
+        ]);
+});