Add cond. return type for wp_list_pages()

functionMap.php

@@ -49,6 +49,7 @@
     'WP_Http::head' => [$httpReturnType],
     'WP_Http::post' => [$httpReturnType],
     'WP_Http::request' => [$httpReturnType],
+    'wp_list_pages' => ['($args is array{echo: false} ? string : void)'],
     'WP_List_Table::set_pagination_args' => ['void', 'args' => 'array{total_items?: int, total_pages?: int, per_page?: int}'],
     'wp_next_scheduled' => [null, 'args' => $cronArgsType],
     'WP_Query::have_posts' => [null, '@phpstan-impure' => ''],

tests/TypeInferenceTest.php

@@ -33,6 +33,7 @@ public function dataFileAsserts(): iterable
         yield from $this->gatherAssertTypes(__DIR__ . '/data/term_exists.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_debug_backtrace_summary.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_error_parameter.php');
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_list_pages.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_rest_request.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_theme.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wpdb.php');

tests/data/wp_list_pages.php

@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * Note:
+ * Starting from PHPStan 1.10.49, void types, including void in unions, are
+ * transformed into null.
+ *
+ * @link https://github.com/phpstan/phpstan-src/pull/2778
+ */
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use function wp_list_pages;
+use function PHPStan\Testing\assertType;
+
+// Default value of true
+assertType('null', wp_list_pages());
+
+// Explicit value of true
+assertType('null', wp_list_pages(['echo' => true, 'key' => 'value']));
+
+// Explicit value of false
+assertType('string', wp_list_pages(['echo' => false, 'key' => 'value']));
+
+// Unknown value
+assertType('string|null', wp_list_pages(['echo' => (bool)$GET['echo'], 'key' => 'value']));

wordpress-stubs.php

@@ -132073,6 +132073,7 @@ function wp_dropdown_pages($args = '')
      *   post_type?: string,
      *   post_status?: string|array,
      * } $args
+     * @phpstan-return ($args is array{echo: false} ? string : void)
      */
     function wp_list_pages($args = '')
     {