AdminerJsonPreview generates error

[xyboox]

On one of my servers, when enabling this plugin, the page load is interrupted when viewing data that contains JSON objects. The error I see in chrome console is:

Uncaught TypeError: Cannot read property 'getElementsByTagName' of null at HTMLDocument.init

However, I noticed the error is triggered by line #77 in AdminerTheme.php ( although, I emphasize it only happens when JSON plugin is loaded ).

About env.:
OS: Ubuntu 18.04.5 LTS
Webserver: Apache 2

[peterpp]

I can't imagine a way how AdminerJsonPreview plugin can cause this error. This plugin modifies different parts of HTML page. You are referring to this code:

var menu = document.getElementById("menu");
var button = menu.getElementsByTagName("h1")[0];

Variable menu should be defined because element with ID "menu" is part of the core HTML generated by Adminer itself. Are you using any other custom plugins? Do you see <div id="menu"> in HTML code?

[xyboox]

Well... here's the thing: I believe is some racing condition here. When using this plugin, the error is thrown before the entire page gets loaded ( so to answer to your question: no, there is no <div id="menu"> in the html code ).

[peterpp]

Could you provide more details? What browser do you use, what Adminer page do you open and what plugins do you use?

[xyboox]

Sure: using latest Chrome on macOS ( Catalina ), Adminer v4.7.8 with these plugins only:

1. AdminerJsonPreview
2. AdminerLoginServers
3. AdminerTheme

Regards!