Unexpected "Unable to Fetch Commits" Error

[dalnoki]

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

Since May 8, 2025, the customer's GitHub integration for their repository has begun failing with a 404 when trying to hit a compare endpoint that references a branch or tag named "ul". Specifically, the failing URL is:

https://api.github.com/repos/repo/name/compare/id...ul

To the best to their knowledge, there has never been a branch, tag, or commit identifier called ul in this repo. This error does not occur with any of our other repositories, only this one.

The customer confirmed that

• they have Read and write access to the repo and that they are selected ion GH's side as well
• they applied the steps mentioned here
• the id is a valid commit and that it is pushed up to GitHub for the repository
• they checked both https://github.com/repo/name/releases and https://github.com/repo/name/tags and ul does not appear there
• they reinstalled the integration but the problem still persists

Additional details are in the shadow Jira ticket.

Expected Result

No 404 errors

Actual Result

A 404 is returned because ul is not a valid ref (branch, tag, or SHA).

Product Area

Settings - Integrations

Link

No response

DSN

No response

Version

No response

[getsantry]

Routing to @getsentry/product-owners-settings-integrations for triage ⏲️

[getsantry]

Auto-routing to @getsentry/product-owners-settings-integrations for triage ⏲️

[sentaur-athena]

Added to the current rotation cycle to take a look.

[cathteng]

How are they attaching commits to their release? We are parsing ul as the end_sha from the list of refs they are providing us

sentry/src/sentry/tasks/commits.py

Lines 154 to 160 in 397cff0

	end_sha = ref["commit"]
	provider = provider_cls(id=repo.provider)
	try:
	if is_integration_provider(provider.id):
	repo_commits = provider.compare_commits(repo, start_sha, end_sha)
	else:
	repo_commits = provider.compare_commits(repo, start_sha, end_sha, actor=user)

[cathteng]

This seems like an issue on the customer's side. Feel free to reopen if there is any new information