Add missing return type hints where possible

lib/Db/PDOError.php

@@ -7,7 +7,7 @@ declare(strict_types=1);
 namespace JKingWeb\Arsse\Db;
 
 trait PDOError {
-    public function exceptionBuild() {
+    public function exceptionBuild(): array {
         if ($this instanceof Statement) {
             $err = $this->st->errorInfo();
         } else {

lib/Db/PDOResult.php

@@ -16,11 +16,11 @@ class PDOResult extends AbstractResult {
 
     // actual public methods
 
-    public function changes() {
+    public function changes(): int {
         return $this->rows;
     }
 
-    public function lastId() {
+    public function lastId(): int {
         return $this->id;
     }
 

lib/Db/Result.php

@@ -17,6 +17,6 @@ interface Result extends \Iterator {
     public function getAll(): array;
     public function getValue();
 
-    public function changes();
+    public function changes(): int;
-    public function lastId();
+    public function lastId(): int;
 }

lib/Db/ResultAggregate.php

@@ -15,13 +15,13 @@ class ResultAggregate extends AbstractResult {
 
     // actual public methods
 
-    public function changes() {
+    public function changes(): int {
         return array_reduce($this->data, function ($sum, $value) {
             return $sum + $value->changes();
         }, 0);
     }
 
-    public function lastId() {
+    public function lastId(): int {
         return $this->data[sizeof($this->data) - 1]->lastId();
     }
 

lib/Db/ResultEmpty.php

@@ -9,11 +9,11 @@ namespace JKingWeb\Arsse\Db;
 use JKingWeb\Arsse\Db\Exception;
 
 class ResultEmpty extends AbstractResult {
-    public function changes() {
+    public function changes(): int {
         return 0;
     }
 
-    public function lastId() {
+    public function lastId(): int {
         return 0;
     }
 

lib/Db/SQLite3/ExceptionBuilder.php

@@ -11,7 +11,7 @@ use JKingWeb\Arsse\Db\ExceptionInput;
 use JKingWeb\Arsse\Db\ExceptionTimeout;
 
 trait ExceptionBuilder {
-    public function exceptionBuild() {
+    public function exceptionBuild(): array {
         switch ($this->db->lastErrorCode()) {
             case self::SQLITE_BUSY:
                 return [ExceptionTimeout::class, 'general', $this->db->lastErrorMsg()];

lib/Db/SQLite3/Result.php

@@ -17,11 +17,11 @@ class Result extends \JKingWeb\Arsse\Db\AbstractResult {
 
     // actual public methods
 
-    public function changes() {
+    public function changes(): int {
         return $this->rows;
     }
 
-    public function lastId() {
+    public function lastId(): int {
         return $this->id;
     }