More PHPStan level 6 cleanups, all remaining .inc files

api/ApiRouter.inc

@@ -57,9 +57,8 @@ class ApiRouter
      * Route an API call to its specific handler.
      *
      * @param array<string, string|string[]> $query_params
-     * @return mixed
      */
-    public function route(string $url, array $query_params)
+    public function route(string $url, array $query_params): mixed
     {
         $node = $this->root;
         $data = [];
@@ -118,8 +117,7 @@ class ApiRouter
         throw new InvalidAPI($path, $part, $children);
     }
 
-    /** @return mixed */
-    public function request(bool $raw = false)
+    public function request(bool $raw = false): mixed
     {
         if ($raw) {
             return file_get_contents('php://input');

api/api_common.inc

@@ -9,7 +9,7 @@
  *
  * @param array<string, string|string[]> $query_params
  */
-function get_flag_value(array $query_params, string $flagname)
+function get_flag_value(array $query_params, string $flagname): ?bool
 {
     if (!isset($query_params[$flagname])) {
         return null;

api/exceptions.inc

@@ -94,6 +94,7 @@ class UnexpectedError extends ApiException
 
 class InvalidAPI extends ApiException
 {
+    /** @param string[] $children */
     public function __construct(string $url, ?string $part, array $children, int $code = 8)
     {
         if (is_null($part)) {
@@ -114,7 +115,8 @@ class InvalidAPI extends ApiException
 
 class MethodNotAllowed extends ApiException
 {
-    public function __construct(string $url, string $invalid, array $valids, $code = 9)
+    /** @param string[] $valids */
+    public function __construct(string $url, string $invalid, array $valids, int $code = 9)
     {
         $valid = implode(", ", $valids);
         $message = "API endpoint $url: Method $invalid not supported. Valid methods: $valid.";

api/v1_docs.inc

@@ -2,7 +2,12 @@
 include_once($relPath.'faq.inc');
 include_once("api_common.inc");
 
-/** @param array<string, string|string[]> $query_params */
+/**
+ * @param array<string, mixed> $data
+ * @param array<string, string|string[]> $query_params
+ * @return string[]
+ *     List of document IDs
+ */
 function api_v1_documents(string $method, array $data, array $query_params): array
 {
     global $external_faq_overrides;
@@ -23,7 +28,10 @@ function api_v1_documents(string $method, array $data, array $query_params): arr
     return $docs;
 }
 
-/** @param array<string, string|string[]> $query_params */
+/**
+ * @param array<string, mixed> $data
+ * @param array<string, string|string[]> $query_params
+ */
 function api_v1_document(string $method, array $data, array $query_params): string
 {
     $lang_code = $query_params["language_code"] ?? "en";
@@ -36,6 +44,10 @@ function api_v1_document(string $method, array $data, array $query_params): stri
     return $faq_url;
 }
 
+/**
+ * @param array<string, mixed> $data
+ * @return array<string, string>
+ */
 function api_v1_dictionaries(string $method, array $data): array
 {
     $dict_list = get_languages_with_dictionaries();