cs fix + change log

Author: Dmytro Vyshnevskyi

src/Core/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## NOT RELEASED
 
+### Fixed
+- SignerV4: sort canonical query parameters **after** URI-encoding (per AWS SigV4). Fixes incorrect ordering for array-style keys (e.g., `transaction_ids[10]` vs `transaction_ids[1]`), which could cause `The request signature we calculated does not match the signature you provided`. See: https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_sigv-create-signed-request.html
+
+
 ## 1.27.0
 
 ### Added

src/Core/src/Signer/SignerV4.php

@@ -321,7 +321,7 @@ private function buildCanonicalQuery(Request $request): string
             return '';
         }
 
-        uksort($query, static fn($a, $b) => strcmp(rawurlencode($a), rawurlencode($b)));
+        uksort($query, static fn ($a, $b) => strcmp(rawurlencode($a), rawurlencode($b)));
         $encodedQuery = [];
         foreach ($query as $key => $values) {
             if (!\is_array($values)) {