Passing null to preg_match is deprecated #35

Job	Run time
ci / check if job needs to run	4s
ci / prepare test matrix	9s
ci / MOODLE_310_STABLE - pgsql - php 7.2 - tool_redirects	3m 5s
ci / MOODLE_311_STABLE - mariadb - php 7.3 - tool_redirects	2m 34s
ci / MOODLE_33_STABLE - mariadb - php 7.1 - tool_redirects	3m 24s
ci / MOODLE_34_STABLE - pgsql - php 7.1 - tool_redirects	2m 29s
ci / MOODLE_35_STABLE - mariadb - php 7.1 - tool_redirects	2m 53s
ci / MOODLE_35_STABLE - pgsql - php 7.1 - tool_redirects	2m 27s
ci / MOODLE_35_STABLE - mariadb - php 7.2 - tool_redirects	2m 44s
ci / MOODLE_36_STABLE - mariadb - php 7.1 - tool_redirects	2m 37s
ci / MOODLE_35_STABLE - pgsql - php 7.2 - tool_redirects	2m 28s
ci / MOODLE_37_STABLE - pgsql - php 7.2 - tool_redirects	2m 42s
ci / MOODLE_38_STABLE - mariadb - php 7.3 - tool_redirects	3m 9s
ci / MOODLE_39_STABLE - mariadb - php 7.2 - tool_redirects	3m 0s
ci / MOODLE_39_STABLE - pgsql - php 7.2 - tool_redirects	2m 57s
ci / MOODLE_39_STABLE - mariadb - php 7.3 - tool_redirects	2m 49s
ci / MOODLE_39_STABLE - pgsql - php 7.3 - tool_redirects	2m 50s
ci / MOODLE_400_STABLE - pgsql - php 7.3 - tool_redirects	3m 0s
ci / MOODLE_401_STABLE - pgsql - php 7.4 - tool_redirects	3m 1s
ci / MOODLE_401_STABLE - mariadb - php 7.4 - tool_redirects	3m 3s
ci / MOODLE_401_STABLE - pgsql - php 8.0 - tool_redirects	3m 5s
ci / MOODLE_401_STABLE - mariadb - php 8.0 - tool_redirects	3m 1s
ci / Release to the Moodle plugin directory	0s
	57m 31s

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