Bug #69038 [Com]: switch(SOMECONSTANT) misbehaves

Edit report at https://bugs.php.net/bug.php?id=69038&edit=1 ID: 69038 Comment by: php at bof dot de Reported by: php at bof dot de Summary: switch(SOMECONSTANT) misbehaves Status: Open Type: Bug Package: opcache Operating System: Linux PHP Version: 5.6.5 Block user comment: N Private report: N New Comment: I cannot get it to segfault / dump core on an --enable-debug build. Weird. Tried it a few hundred times. However the issue is still there (outputs foo and default). With the production build, identical in all other regards, I can get it to segfault in one of about 10 runs. Here is a backtrace of such a run, for whatever that's worth: Core was generated by `php -d opcache.enable_cli=1 /home/patrick/webdev/switch_const_myconst.php'. Program terminated with signal 11, Segmentation fault. #0 0x0000000000000021 in ?? () (gdb) bt #0 0x0000000000000021 in ?? () #1 0x0000000000853d3b in zend_hash_destroy (ht=0x7f941c441e18) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_hash.c:548 #2 0x0000000000844893 in _zval_dtor_func (zvalue=0x7f941c4401b0) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_variables.c:45 #3 0x000000000087368a in _zval_dtor (execute_data=0x7f941c4401d0) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_variables.h:35 #4 ZEND_FREE_SPEC_TMP_HANDLER (execute_data=0x7f941c4401d0) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_vm_execute.h:7956 #5 0x00000000008b07c9 in execute_ex (execute_data=0x7f941c4401d0) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_vm_execute.h:363 #6 0x00007f941467947b in xdebug_execute_ex (execute_data=0x7f941c4401d0) at /usr/src/phb/build/release-5.6.5/xdebug/xdebug.c:1437 #7 0x00000000008e7ac2 in zend_do_fcall_common_helper_SPEC ( execute_data=<value optimized out>) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_vm_execute.h:592 #8 0x00000000008b07c9 in execute_ex (execute_data=0x7f941c4400e0) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend_vm_execute.h:363 #9 0x00007f941467947b in xdebug_execute_ex (execute_data=0x7f941c4400e0) at /usr/src/phb/build/release-5.6.5/xdebug/xdebug.c:1437 #10 0x00000000008472d4 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /usr/src/phb/build/release-5.6.5/php-src/Zend/zend.c:1341 #11 0x00000000007e3bfe in php_execute_script (primary_file=0x7fffaabc56f0) at /usr/src/phb/build/release-5.6.5/php-src/main/main.c:2584 #12 0x00000000008eaf89 in do_cli (argc=4, argv=0x1f00e90) at /usr/src/phb/build/release-5.6.5/php-src/sapi/cli/php_cli.c:994 #13 0x00000000008eb91c in main (argc=4, argv=0x1f00e90) at /usr/src/phb/build/release-5.6.5/php-src/sapi/cli/php_cli.c:1378 Previous Comments: ------------------------------------------------------------------------ [2015-02-12 08:43:18] php at bof dot de Description: ------------ Using a self built PHP 5.6.5, opcache enabled: switch(ARBITRARYCONSTANTS) misbehaves: goes to the default case, unless the matching thing is the first case. opcache is enabled like this: zend_extension=/opt/php/extensions/opcache.so opcache.enable_cli=1 Also happens under mod_php without opcache.enable_cli. No other opcache settings made, but happens also with our usual production settings, so that should not matter The result is usually what I show under "actual result", below, but on some runs I also see a segmentation fault, or the correct behaviour. I can reproduce the problem when using global "const MYCONST = 'foo';", but apparently _not_ with a class constant (class foo { const MYCONST = 'foo'; } Will create a debug build of PHP soon and try to capture a backtrace for a test run where it runs into a segmentation violation. Might take some time, though... Test script: --------------- <?php define('MYCONST', 'foo'); function goodswitch() { switch(MYCONST) { case 'foo': return 'foo'; case 'bar': return 'bar'; default: return 'default'; } } function badswitch() { switch(MYCONST) { case 'bar': return 'bar'; case 'foo': return 'foo'; default: return 'default'; } } var_dump(goodswitch()); var_dump(badswitch()); ?> Expected result: ---------------- string(3) "foo" string(3) "foo" Actual result: -------------- string(3) "foo" string(7) "default" ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=69038&edit=1