Quick summary

On a site with a pre-site-editor theme like Baskerville, Twenty Twenty, or even Twenty Twenty-One, using the Query Loop block causes a page to enter an infinite loop and eventually time out. This only happens if "Inherit query from template" is set.

This appears to be a wpcom-only bug. I've tried the same steps on a brand-new WP 6.0 site and the issue does not occur.

The issue does not occur in very new themes like Twenty Twenty-Two.

Steps to reproduce

1. Create a new site on WordPress.com or use an existing site.
2. Set the site's theme to Twenty Twenty-One or Baskerville.
3. Create a new post.
4. Inside the post content add a Query Loop block. Choose any layout for it.
5. In the block settings, turn on "Inherit query from template".
6. Publish the post.
7. View the post.

What you expected to happen

To see the post.

What actually happened

A blank page is shown after a long loading time. In the server logs, we see a Fatal error: Allowed memory size of 536870912 bytes exhausted, but the stack trace varies considerably across all sorts of files.

Sometimes instead of a blank page, we get the same post repeated over and over again.

Browser

Google Chrome/Chromium

Context

Automatticians discovered this from Payments logs.

Platform (Simple, Atomic, or both?)

Simple, Atomic

Other notes

No response

Reproducibility

Consistent

Severity

Some (< 50%)

Available workarounds?

Yes, easy to implement

Workaround details

Change the Query Loop block to turn off "Inherit query from template".