Fix bug #79410 (system() swallows last chunk if it is exactly 4095 bytes without newline)

Closes GH-5292.

Author: Christian Schneider

NEWS

@@ -24,6 +24,10 @@ PHP                                                                        NEWS
   . Fixed bug #79393 (Null coalescing operator failing with SplFixedArray).
     (cmb)
 
+- Standard:
+  . Fixed bug #79410 (system() swallows last chunk if it is exactly 4095 bytes
+    without newline). (Christian Schneider)
+
 - Zip:
   . Fixed Bug #79296 (ZipArchive::open fails on empty file). (Remi)
 

ext/standard/exec.c

@@ -162,6 +162,13 @@ PHPAPI int php_exec(int type, char *cmd, zval *array, zval *return_value)
 			b = buf;
 		}
 		if (bufl) {
+			/* output remaining data in buffer */
+			if (type == 1 && buf != b) {
+				PHPWRITE(buf, bufl);
+				if (php_output_get_level() < 1) {
+					sapi_flush();
+				}
+			}
 			/* strip trailing whitespaces if we have not done so already */
 			if ((type == 2 && buf != b) || type != 2) {
 				l = bufl;

ext/standard/tests/misc/bug79410.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Bug #79410 (system() swallows last chunk if it is exactly 4095 bytes without newline)
+--FILE--
+<?php
+ob_start();
+system(getenv('TEST_PHP_EXECUTABLE') . ' -n -r "echo str_repeat(\".\", 4095);"');
+var_dump(strlen(ob_get_clean()));
+?>
+--EXPECT--
+int(4095)