Error in test site but not in identical live site

[HeleneWallis]

I was getting a PHP warning in the logs on my wamp64 test site, that a specific constant was being defined twice. Sure enough, it was defined in two separate places in \includes\filenames.php. I fixed that and am no longer getting that warning. But the filenames.php program on my live site is identical and I'm not getting that message in the logs from the live site. The only difference I see is that the live site is running PHP 5.6.40, and I have 8.0.26 on the test site. I'm not clued up enough yet about PHP to know if that's what is triggering an error on the test site. Does that sound reasonable, though?

[dbltoe]

You may find that the settings in Admin >> Configuration >> Logging are different.

[mc12345678]

Generally speaking, yes use of php 8.x where a define is duplicated is likely to cause an attempt to generate a log. What is suggested above is that in more recent versions of zenith cart there is a configuration option to prevent generating logs for duplicate definitions. That configuration setting didn't become necessary until newer php versions began reporting it as an issue.

[swguy]

> The only difference I see is that the live site is running PHP 5.6.40, and I have 8.0.26 on the test site.

This is a REALLY big difference. Lots and lots and lots of changes from PHP 5.6-> PHP7, and then even more from PHP7->PHP8.
You will generally get more logs with old code in higher versions of PHP unless you take steps to improve your code. When you're ready to move to PHP8, you will want to also upgrade to Zen Cart 1.5.8.

[HeleneWallis]

Thanks all, I do have a test installation of 1.5.8 online, but my local installation obviously needs to go back to an earlier version. I appreciate the extended explanations very much.