Add a new imap_is_open() function to check that a connection object is still valid

ext/imap/php_imap.c

@@ -781,6 +781,24 @@ PHP_FUNCTION(imap_reopen)
 }
 /* }}} */
 
+PHP_FUNCTION(imap_is_open)
+{
+	zval *imap_conn_obj;
+	php_imap_object *imap_conn_struct;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "O", &imap_conn_obj, php_imap_ce) == FAILURE) {
+		RETURN_THROWS();
+	}
+
+	/* Manual reimplementation of the GET_IMAP_STREAM() macro that doesn't throw */
+	imap_conn_struct = imap_object_from_zend_object(Z_OBJ_P(imap_conn_obj));
+	/* Stream was closed */
+	if (imap_conn_struct->imap_stream == NULL) {
+		RETURN_FALSE;
+	}
+	RETURN_TRUE;
+}
+
 /* {{{ Append a new message to a specified mailbox */
 PHP_FUNCTION(imap_append)
 {

ext/imap/php_imap.stub.php

@@ -411,6 +411,8 @@ function imap_reopen(IMAP\Connection $imap, string $mailbox, int $flags = 0, int
 
     function imap_close(IMAP\Connection $imap, int $flags = 0): bool {}
 
+    function imap_is_open(IMAP\Connection $imap): bool {}
+
     function imap_num_msg(IMAP\Connection $imap): int|false {}
 
     function imap_num_recent(IMAP\Connection $imap): int {}

ext/imap/tests/imap_is_open.phpt

@@ -0,0 +1,37 @@
+--TEST--
+Test imap_is_open()
+--EXTENSIONS--
+imap
+--SKIPIF--
+<?php
+require_once(__DIR__.'/setup/skipif.inc');
+?>
+--FILE--
+<?php
+
+// include file for required variables in imap_open()
+require_once(__DIR__.'/setup/imap_include.inc');
+
+$mailbox_suffix = 'imapisopen';
+
+// set up temp mailbox with 0 messages
+$stream_id = setup_test_mailbox($mailbox_suffix, 0, $mailbox);
+
+var_dump(imap_is_open($stream_id));
+
+// Close connection
+var_dump(imap_close($stream_id));
+var_dump(imap_is_open($stream_id));
+
+?>
+--CLEAN--
+<?php
+$mailbox_suffix = 'imapisopen';
+require_once(__DIR__.'/setup/clean.inc');
+?>
+--EXPECT--
+Create a temporary mailbox and add 0 msgs
+New mailbox created
+bool(true)
+bool(true)
+bool(false)