Smarty 3/4 - Fix prepending extension template directories

[colemanw]

Overview

Fixes civicrm/org.civicrm.contactlayout#143

Before

Extensions would prepend their directories under smarty2, but smarty3 & 4 would append them, breaking template overrides.

After

Smarty 2,3&4 all prepend template directories

Technical Details

It was a bit tough to wrangle the same behavior out of all 3 versions, but resorting to lowest-common-denominator getter/setter functions works well.

Note: I ended up adding a special case for Smarty2 since it doesn't have getter/setter functions (at least not on older versions of Civi, which we still support via mixin shims). So this PR no longer depends on civicrm/civicrm-packages#397

[civibot]

🤖 Thank you for contributing to CiviCRM! ❤️ We will need to test and review this PR. 👷

Introduction for new contributors...

• If this is your first PR, an admin will greenlight automated testing with the command ok to test or add to whitelist.
• A series of tests will automatically run. You can see the results at the bottom of this page (if there are any problems, it will include a link to see what went wrong).
• A demo site will be built where anyone can try out a version of CiviCRM that includes your changes.
• If this process needs to be repeated, an admin will issue the command test this please to rerun tests and build a new demo site.
• Before this PR can be merged, it needs to be reviewed. Please keep in mind that reviewers are volunteers, and their response time can vary from a few hours to a few weeks depending on their availability and their knowledge of this particular part of CiviCRM.
• A great way to speed up this process is to "trade reviews" with someone - find an open PR that you feel able to review, and leave a comment like "I'm reviewing this now, could you please review mine?" (include a link to yours). You don't have to wait for a response to get started (and you don't have to stop at one!) the more you review, the faster this process goes for everyone 😄
• To ensure that you are credited properly in the final release notes, please add yourself to contributor-key.yml
• For more information about contributing, see CONTRIBUTING.md.

Quick links for reviewers...

• ➡️ PR Demo site (can be rebuilt with the command test this please).
• 📖 Review standards
• 🗒️ Review template (brief or verbose)

➡️ Online demo of this PR 🔗

[totten]

Since this is specifically aimed at the various edges of Smarty (2/3/4/5), I ran the mixin test for smarty-v2 with each version of Smarty. All passed. 👍

(There were php82 warnings, esp w/smarty2+3+5, but I believe they're all pre-existing.)

I'll do one more check to with civix using this in a backport...

[totten]

OK, yup, backport loads fine with civix on an older version of CiviCRM.

[eileenmcnaughton]

Just noting that in our experience getTemplateDir() can be very slow to call - ie we got up to 7 seconds with repeated calling. Not completely sure why it gets slower - but it is on realPath() within that function it slows down. Not too sure the fix as I got such a big improvement from one of the other things on https://lab.civicrm.org/dev/core/-/issues/5243 that this might not matter if we resolve that

[eileenmcnaughton]

I performance tested - if it wasn't for the first line in this table this would be in my sights ... https://lab.civicrm.org/dev/core/-/issues/5243#note_164882

[eileenmcnaughton]

Ok - this does seem to be the culprit for the slow down - but we have been firing up some variants that address it & we can look at the pre-existing issue once Montreal is online