Undefined symbol: pdo_parse_params when loading dynamic library 'pdo_mysql'

[yaner-here]

Description

I installed PHP-8.1.2 and php-mysql extension on Ubuntu 22.04. After enabling it manually in php.ini, PHP keeps warning that there's a undefined symbol: pdo_parse_params and refuses to load it.

root@linux /v/w/html# php --version                                                                                                                                         (base) 
PHP Warning:  PHP Startup: Unable to load dynamic library 'pdo_mysql' (tried: /usr/lib/php/20210902/pdo_mysql (/usr/lib/php/20210902/pdo_mysql: undefined symbol: pdo_parse_params), /usr/lib/php/20210902/pdo_mysql.so (/usr/lib/php/20210902/pdo_mysql.so: undefined symbol: pdo_parse_params)) in Unknown on line 0
PHP 8.1.2-1ubuntu2.8 (cli) (built: Nov  2 2022 13:35:25) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.2, Copyright (c) Zend Technologies
    with Zend OPcache v8.1.2-1ubuntu2.8, Copyright (c), by Zend Technologies

And I'm sure that it has been installed.

root@linux /v/w/html [100]# apt install php-mysql                                                                                                                           (base) 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
php-mysql is already the newest version (2:8.1+92ubuntu1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

root@linux /v/w/html# php -m
[PHP Modules]
......
PDO
pdo_mysql
......

root@linux /v/w/html# tree /usr/lib/php/
/usr/lib/php/
|-- 20210902
|   |-- ......
|   |-- pdo.so
|   |-- pdo_mysql.so
|   |-- ......

But readelf told me that pdo_parse_params does exist.

root@linux /u/l/p/20210902# readelf -a pdo_mysql.so | grep "pdo_parse"
000000008de8  000100000007 R_X86_64_JUMP_SLO 0000000000000000 pdo_parse_params + 0
000000008f98  003e00000007 R_X86_64_JUMP_SLO 0000000000000000 php_pdo_parse_dat[...] + 0
     1: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND pdo_parse_params
    62: 0000000000000000     0 NOTYPE  GLOBAL DEFAULT  UND php_pdo_parse_da[...]

I'm so confusing about this problem. Why PHP can't identify this pdo_parse_params?

PHP Version

PHP 8.1.2

Operating System

Ubuntu 22.04

[cmb69]

pdo_parse_params should be exported from pdo.so (not pdo_mysql.so)

root@linux /v/w/html# php -m
[PHP Modules]
......
PDO
pdo_mysql
......

If pdo_mysql can't be loaded, it is not supposed to be listed by php -m. It seems there is something wrong with your setup (maybe different PHP versions are interfering).

[yaner-here]

I have figured out the solution: Loading one extension twice more will confuse PHP and cause unpredictable problems.

PHP will automatically try to load each extension that has a config file existing in /etc/php/8.1/cli/conf.d or other paths depending on your PHP versions:

root@linux /e/p/8/c/conf.d# ls
10-mysqlnd.ini   20-dom.ini       20-iconv.ini      20-readline.ini   20-tokenizer.ini
10-opcache.ini   20-exif.ini      20-intl.ini       20-shmop.ini      20-xmlreader.ini
10-pdo.ini       20-ffi.ini       20-mbstring.ini   20-simplexml.ini  20-xmlwriter.ini
15-xml.ini       20-fileinfo.ini  20-mysqli.ini     20-sockets.ini    20-xsl.ini
20-calendar.ini  20-ftp.ini       20-pdo_mysql.ini  20-sysvmsg.ini
20-ctype.ini     20-gd.ini        20-phar.ini       20-sysvsem.ini
20-curl.ini      20-gettext.ini   20-posix.ini      20-sysvshm.ini

root@linux /e/p/8/c/conf.d# cat 20-pdo_mysql.ini
; configuration for php mysql module
; priority=20
extension=pdo_mysql.so

Here's a declaration extension=pdo_mysql.so. But I make another declaration in php.ini by uncommenting that line:

root@linux /e/p/8/c/conf.d# cat ../php.ini | grep "extension=pdo_mysql"
extension=pdo_mysql

After commenting this line, everything works like a charm.