Fixed bug #80256

Remove the transfer_encoding stream filter immediately when we
destroy the old stream, to make sure it doesn't get attached to
the new stream.

Author: nikic

NEWS

@@ -13,6 +13,10 @@ PHP                                                                        NEWS
 - Opcache:
   . Fixed bug #80255 (Opcache bug (bad condition result) in 8.0.0rc1). (Nikita)
 
+- Standard:
+  . Fixed bug #80256 (file_get_contents strip first line with chunked encoding
+    redirect). (Nikita)
+
 15 Oct 2020, PHP 8.0.0RC2
 
 - Core:

ext/standard/http_fopen_wrapper.c

@@ -842,6 +842,11 @@ static php_stream *php_stream_url_wrap_http_ex(php_stream_wrapper *wrapper,
 		php_stream_close(stream);
 		stream = NULL;
 
+		if (transfer_encoding) {
+			php_stream_filter_free(transfer_encoding);
+			transfer_encoding = NULL;
+		}
+
 		if (location[0] != '\0') {
 
 			char new_path[HTTP_HEADER_BLOCK_SIZE];
@@ -958,10 +963,6 @@ static php_stream *php_stream_url_wrap_http_ex(php_stream_wrapper *wrapper,
 		if (transfer_encoding) {
 			php_stream_filter_append(&stream->readfilters, transfer_encoding);
 		}
-	} else {
-		if (transfer_encoding) {
-			php_stream_filter_free(transfer_encoding);
-		}
 	}
 
 	return stream;

ext/standard/tests/http/bug80256.phpt

@@ -0,0 +1,29 @@
+--TEST--
+Bug #80256: file_get_contents strip first line with chunked encoding redirect
+--SKIPIF--
+<?php require 'server.inc'; http_server_skipif(); ?>
+--INI--
+allow_url_fopen=1
+--FILE--
+<?php
+require 'server.inc';
+
+$responses = array(
+    "data://text/plain,HTTP/1.1 302 Moved Temporarily\r\n"
+    . "Location: /try-again\r\n"
+    . "Transfer-Encoding: chunked\r\n\r\n"
+    . "0\r\n\r\n",
+    "data://text/plain,HTTP/1.1 200 Ok\r\n"
+    . "Transfer-Encoding: chunked\r\n\r\n"
+    . "4\r\n1234\r\n0\r\n\r\n",
+);
+
+['pid' => $pid, 'uri' => $uri] = http_server($responses, $output);
+
+var_dump(file_get_contents($uri));
+
+http_server_kill($pid);
+
+?>
+--EXPECT--
+string(4) "1234"