In writing T269489#6679953, I thought it had something to do with phan. However, it seems like everything is using PHP 7.3: for instance, looking at https://integration.wikimedia.org/ci/job/composer-package-php74-docker/3857/consoleFull, you can read:
parallel-lint . --exclude vendor --exclude tests/integration/weirdsyntax --exclude tests/integration/assignop
PHP 7.3.21 | 10 parallel jobs
Indeed, the image inherits from the php73 one:
...
FROM {{ "php73" | image_tag }}
...Change 647343 had a related patch set uploaded (by Hashar; owner: Hashar):
[integration/config@master] dockerfiles: use proper php in composer-package-php74
Change 647346 had a related patch set uploaded (by Hashar; owner: Hashar):
[integration/config@master] jjb: switch composer-package jobs to actually use php74
Change 647343 merged by jenkins-bot:
[integration/config@master] dockerfiles: use proper php in composer-package-php74
Change 647346 merged by jenkins-bot:
[integration/config@master] jjb: switch composer-package jobs to actually use php74
Done. That was caused by a typo, the php74 based image inherited from php73 which well ... provides php 7.3. Kunal pointed out yesterday that we used to have a shell oneliner asserting the proper version of PHP was used, though that is from a time when we had multiple PHP versions installed and in this case I guess the oneliner would have been copy pasted as is and would not have detected it.
In an ideal world we would have CI building the images and would be able to run some smoke tests against the images. Such as ensuring that any image containing php74 in its name actually have php pointing to 7.4. But that is an ideal world we are not in.
Anyway it should be fixed now.