Bug: PR component doesn't render some of the time

[charliemic]

Select Topic Area

Bug

Body

We’re experiencing an issue where for some PRs the merge component doesn’t render on GitHub.com (see screenshot below).

It appears for these PRs, a request to the /merging endpoint returns 502 Gateway Timeout (but with HTML in the payload showing a timeout error page with a unicorn visual). In successful PRs, this returns the HTML to render that component.

We've not been able to identify which PRs will exhibit this behaviour. Closing and re-opening a PR exhibiting this behaviour often resolves it.

[charliemic]

Pretty sure it's a server side issue.

Client side issues ruled out:

• Browser (tested different browsers)
• Cookies (incognito & cleared cookies)
• Extensions (tested no extensions)
• Network (tested multiple different networks and VPNs)

Two other pieces of evidence that suggest server-side:

• The 502 response from the server
• Experienced by multiple users on the same PRs with different client setups

[charliemic]

It's definitely not client side. The issue persists consistently for the same PRs regardless of cookies or client state.

A 502 response from the server co-inciding with 16s+ response time from a particular endpoint indicates some server-side issue, most likely poor optimisation on a database query (or queries).

[charliemic]

Received a response from Github support that this was a known bug that was fixed in a release around 5th August