Add cond. return type and type narrowing for taxonomy_exists

functionMap.php

@@ -133,6 +133,7 @@
     'stripslashes_deep' => ['T', '@phpstan-template' => 'T', 'value' => 'T'],
     'stripslashes_from_strings_only' => ["(\$value is string ? (\$value is '' ? '' : string) : T)", '@phpstan-template' => 'T', 'value' => 'T|string'],
     'tag_exists' => ["(\$tag_name is 0 ? 0 : (\$tag_name is '' ? null : array{term_id: string, term_taxonomy_id: string}|null))"],
+    'taxonomy_exists' => ['($taxonomy is non-falsy-string ? bool : false)', '@phpstan-impure' => '', '@phpstan-assert-if-true' => '=non-falsy-string $taxonomy'],
     'term_exists' => ["(\$term is 0 ? 0 : (\$term is '' ? null : (\$taxonomy is '' ? string|null : array{term_id: string, term_taxonomy_id: string}|null)))"],
     'the_date' => ['($display is true ? void : string)'],
     'the_modified_date' => ['($display is true ? void : string)'],

tests/TypeInferenceTest.php

@@ -67,6 +67,7 @@ public function dataFileAsserts(): iterable
         yield from $this->gatherAssertTypes(__DIR__ . '/data/sanitize_title_with_dashes.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/size_format.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/stripslashes.php');
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/taxonomy_exists.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/term_exists.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/trailingslashit.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/validate_file.php');

tests/data/taxonomy_exists.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use function taxonomy_exists;
+use function PHPStan\Testing\assertType;
+
+/*
+ * Check return type
+ */
+
+assertType('false', taxonomy_exists(''));
+assertType('false', taxonomy_exists('0'));
+assertType('bool', taxonomy_exists('tax'));
+assertType('bool', taxonomy_exists(Faker::string()));
+assertType('bool', taxonomy_exists(Faker::nonEmptyString()));
+assertType('bool', taxonomy_exists(Faker::nonFalsyString()));
+
+/*
+ * Check impurity
+ */
+
+if (taxonomy_exists('taxonomy')) {
+    assertType('bool', taxonomy_exists('taxonomy'));
+}
+if (! taxonomy_exists('taxonomy')) {
+    assertType('bool', taxonomy_exists('taxonomy'));
+}
+
+$taxonomy = Faker::string();
+if (taxonomy_exists($taxonomy)) {
+    assertType('bool', taxonomy_exists($taxonomy));
+}
+if (! taxonomy_exists($taxonomy)) {
+    assertType('bool', taxonomy_exists($taxonomy));
+}
+
+/*
+ * Check type specification
+ */
+
+$taxonomy = Faker::string();
+if (taxonomy_exists($taxonomy)) {
+    assertType('non-falsy-string', $taxonomy);
+}
+if (! taxonomy_exists($taxonomy)) {
+    assertType('string', $taxonomy);
+}

wordpress-stubs.php

@@ -138187,6 +138187,9 @@ function get_taxonomy($taxonomy)
      *
      * @param string $taxonomy Name of taxonomy object.
      * @return bool Whether the taxonomy exists.
+     * @phpstan-impure
+     * @phpstan-assert-if-true =non-falsy-string $taxonomy
+     * @phpstan-return ($taxonomy is non-falsy-string ? bool : false)
      */
     function taxonomy_exists($taxonomy)
     {