From 745a2ced4aedc8504d868279fbe4f514092b64ae Mon Sep 17 00:00:00 2001
From: "Christoph M. Becker" <cmbecker69@gmx.de>
Date: Fri, 24 Sep 2021 17:16:22 +0200
Subject: [PATCH] Fix #81475: stream_isatty emits warning with attached stream
 wrapper

We must not issue warnings, if `show_err` is false.
---
 ext/standard/tests/filters/bug81475.phpt | 10 ++++++++++
 main/streams/cast.c                      |  4 +++-
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 ext/standard/tests/filters/bug81475.phpt

diff --git a/ext/standard/tests/filters/bug81475.phpt b/ext/standard/tests/filters/bug81475.phpt
new file mode 100644
index 0000000000000..253d5a75ea792
--- /dev/null
+++ b/ext/standard/tests/filters/bug81475.phpt
@@ -0,0 +1,10 @@
+--TEST--
+Bug #81475 (stream_isatty emits warning with attached stream wrapper)
+--FILE--
+<?php
+$stdout = fopen('php://stdout', 'wb');
+stream_filter_append($stdout, 'string.toupper');
+var_dump(stream_isatty($stdout));
+?>
+--EXPECT--
+bool(false)
diff --git a/main/streams/cast.c b/main/streams/cast.c
index 73421a75880c8..2109239effa4e 100644
--- a/main/streams/cast.c
+++ b/main/streams/cast.c
@@ -295,7 +295,9 @@ PHPAPI int _php_stream_cast(php_stream *stream, int castas, void **ret, int show
 	}
 
 	if (php_stream_is_filtered(stream)) {
-		php_error_docref(NULL, E_WARNING, "cannot cast a filtered stream on this system");
+		if (show_err) {
+			php_error_docref(NULL, E_WARNING, "cannot cast a filtered stream on this system");
+		}
 		return FAILURE;
 	} else if (stream->ops->cast && stream->ops->cast(stream, castas, ret) == SUCCESS) {
 		goto exit_success;