Edit customer depriciated null string on customer referal

[gothstone]

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pezcollectors.com, 1.5.8a, PHP 8.1.24
verified admin/customers.php IS stock unmodified

Editing any customer throws the error below. Looks like its because of the empty customer referral.
[16-Oct-2023 08:48:52 America/Chicago] Request URI: /nimda123/index.php?cmd=customers&page=1&cID=25052&action=edit, IP address: 73.67.37.4, Language id 1
#0 [internal function]: zen_debug_error_handler()
#1 /nimda123/customers.php(1061): htmlspecialchars()
#2 /nimda123/index.php(11): require('/home/pcs/publi...')
--> PHP Deprecated: htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /nimda123/customers.php on line 1061.

[gothstone]

The answer is in the upgrading to 1.5.8 doc.
Line 1058 should be changed from:

$cInfo->customers_referral,

to:

$cInfo->customers_referral ?? '',

[lat9]

The answer is in the upgrading to 1.5.8 doc.
Line 1058 should be changed from:

$cInfo->customers_referral,

to:

$cInfo->customers_referral ?? '',

Where did you find this documented (a link, please)? I'm asking because the customers::customers_referral field has been defined as NOT NULL default '' since at least Zen Cart 1.5.5.

[gothstone]

https://docs.zen-cart.com/dev/plugins/upgrading_to_158/
"PHP 8.1 and null strings passed as parameters"
was almost identical to my issue.

I don't see anything about it in my upgrade exceptions, but I DO see that my clean blank 1.5.8 reference DB is set to Null NO with no default. My actual DB is Null Yes Default Null.

It looks like it was always blank until Dec 2011 which corresponds to an upgrade of edit orders, and numinix endicia exporter, and probably a few others. So I'm sure one of my mods went sideways and caused this.

So set default to blank, wipe out the nulls, and set null to no?

[gothstone]

Ugh. Comparing the clean to current, I have a LOT of cleanup/fixing to do

[gothstone]

So thinking on this, clearly I can't trust my database structure. Feel free to move this to another section of the forum, clearly this is NOT a bug in ZC.
I plan to do the following:
1. Create another dev site with a clean ZC_install with a blank DB
2. Drop my prod fileset on top
3. Log into admin, let my mods install
4. Drop on any manual SQL installed for any of my mods
5. Make sure all mods are active and installed
6. Compare structure of THAT DB to my current
7. Build SQL statements to fix all structure and data to align

Does anyone have suggestions on good tools to help with the structure comparison and data correction?

[lat9]

Ugh. Comparing the clean to current, I have a LOT of cleanup/fixing to do

Yikes, the only nullable fields in a standard Zen Cart database are the customers_fax and customers_newsletters fields!