Bug #78066 [Com]: PHP eats the first byte of a program that comes from process substitution

Edit report at https://bugs.php.net/bug.php?id=78066&edit=1 ID: 78066 Comment by: simon at ikanobori dot jp Reported by: octalbugsphp at alvarezp dot org Summary: PHP eats the first byte of a program that comes from process substitution Status: Open Type: Bug Package: *General Issues Operating System: Linux PHP Version: 7.3.5 Block user comment: N Private report: N New Comment: Being part of that discussion, it is important to note that process substitution returns the path to an anonymous pipe which stops existing after the process finishes. Previous Comments: ------------------------------------------------------------------------ [2019-05-25 16:52:01] octalbugsphp at alvarezp dot org Description: ------------ PHP eats the first byte of a program that comes from process substitution After discussion in ##php at Freenode this was found (see the third line, lseek) $ strace php -f <(echo -- '<?php print("hello\n"); ?>') 2>&1 | grep -A 5 'openat.*/dev/fd/63' openat(AT_FDCWD, "/dev/fd/63", O_RDONLY) = 3 fstat(3, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0 read(3, "-- <?php print(\"hello\\n\"); ?>\n", 4096) = 30 lseek(3, 0, SEEK_SET) = -1 ESPIPE (Illegal seek) lstat("/dev/fd/63", {st_mode=S_IFLNK|0500, st_size=64, ...}) = 0 readlink("/dev/fd/63", "pipe:[6195898]", 4096) = 14 Test script: --------------- [ 0][Sat May 25 11:05:07 -0500 -- alvarezp@alvarezp-samsung:~] $ php -f <(echo '<?php print("hello\n"); ?>') ?php print("hello\n"); ?> [ 0][Sat May 25 11:05:11 -0500 -- alvarezp@alvarezp-samsung:~] $ php -f <(echo ' <?php print("hello\n"); ?>') hello [ 0][Sat May 25 11:05:19 -0500 -- alvarezp@alvarezp-samsung:~] $ php -f <(echo -- '<?php print("hello\n"); ?>') - hello Expected result: ---------------- The script should run as expected. The first byte should prevail as part of the script. Actual result: -------------- The first byte is eaten and not interpreted at all. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=78066&edit=1