deprecation warnings in footer template

[OyvindLGjesdal]

Describe the bug

After upgrading to php 8.2, I see deprecation warning and smarty warning:

PHP Deprecated:  trim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/ojs/cache/t_compile/..._0.app.frontendcomponentsfooter.tpl.php on line 57

refers to

https://github.com/pkp/healthSciences/blob/main/templates/frontend/components/footer.tpl#L36

{* Load author biography modals if they exist *}
{if !empty($smarty.capture.authorBiographyModals|trim)}
	{$smarty.capture.authorBiographyModals}
{/if}

Would skipping the trim filter make sense (if it exists as whitespace, it will only input whitespace).

I don't know if this is fixed upstream in smarty, but the smarty version used is the same as the in 3.3 stable branch of pkp-lib, which is 0.2 versions behind main. (v4.3.1).

[asmecher]

@OyvindLGjesdal, what version of OJS are you using, and what version of the health sciences theme?

[OyvindLGjesdal]

3.3.0.17 and a bit behind on the the healthSciences theme 722d2ba

I did a fast check in the stable-3.3 branch for both ojs and the theme to see if the section had changed, or the library version for smarty, and it looked likely to me that the bug was also present there. Haven't confirmed.

[asmecher]

@OyvindLGjesdal, can you quickly verify if this change resolves the issue?

diff --git a/templates/frontend/components/footer.tpl b/templates/frontend/components/footer.tpl
index 3b3e6f2..126ea2c 100644
--- a/templates/frontend/components/footer.tpl
+++ b/templates/frontend/components/footer.tpl
@@ -33,7 +33,7 @@
 </footer><!-- pkp_structure_footer_wrapper -->
 
 {* Load author biography modals if they exist *}
-{if !empty($smarty.capture.authorBiographyModals|trim)}
+{if !empty($smarty.capture.authorBiographyModals|default:""|trim)}
        {$smarty.capture.authorBiographyModals}
 {/if}

[OyvindLGjesdal]

It removes the previous message and returns a different deprecation message:

PHP Deprecated:  Using php-function "trim" as a modifier is deprecated and will be removed in a future release. Use Smarty::registerPlugin to explicitly register a custom modifier. in /var/www/ojs/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_compile_private_modifier.php on line 112

Looking at previous issues on the forum and fixes, I guess trim can also be added to https://github.com/pkp/pkp-lib/blob/stable-3_3_0/classes/template/PKPTemplateManager.inc.php#L259

[asmecher]

@OyvindLGjesdal You're right, thanks -- added here for stable-3_3_0:

https://github.com/pkp/pkp-lib/blob/90a2a55f71d1eac01ef7ba86d8c854d00ad236e6/classes/template/PKPTemplateManager.inc.php#L260

For 3.4.0, it's pkp/pkp-lib@c91897c; for main it's pkp/pkp-lib@cb47652.