GitHub API: check repository for null

[kylos101]

Bug description

Steps to reproduce

Delete a branch in a PR.
Restore it.
Try opening this using the Gitpod browser extension.

Originally discovered here

Workspace affected

n/a

Expected behavior

Should be able to open Gitpod from a branch which was deleted and is now restored.

Example repository

gitpod-io/workspace-images#564

Anything else?

No response

[kylos101]

I think it was just taking Github a long time to restore? Works now, ~26 minutes later. That, or we've got some kind of cache on our side that had to be invalidated.

[geropl]

@AlexTugarev I faintly recall you fixed a similar error in the past? What was it exactly?
@jankeromnes Could this have been re-introduced by the GHE changes? 🤔

[jankeromnes]

Interesting, this looks like #3659, which we had fixed with #3869.

I wonder why it came back. Will have a quick look at where we possibly try to read .repository of null.

Also, FYI, I believe this is indeed GitHub taking some time to fully restore a deleted branch.

---

I wonder if GraphQL calls somehow changed and can now return something like result: { data: null }? 🤔

This could explain why we're trying to read .repository of null in these lines (GitHub Pull Request context parser):

gitpod/components/server/src/github/github-context-parser.ts

Lines 302 to 305 in d2913ae

	if (result.data.repository === null) {
	throw await NotFoundError.create(await this.tokenHelper.getCurrentToken(user), user, this.config.host, owner, repoName);
	}
	const pr = result.data.repository.pullRequest;

before reaching the line that checks whether the branch was deleted (original fix):

gitpod/components/server/src/github/github-context-parser.ts

Lines 314 to 316 in d2913ae

	if (pr.headRef === null) {
	throw new Error(`Could not open pull request ${owner}/${repoName}#${pullRequestNr}. Source branch may have been removed.`);
	}

[AlexTugarev]

@jankeromnes, 💯!

There are several places with the same pattern:
https://github.com/gitpod-io/gitpod/blob/main/components/server/src/github/github-context-parser.ts#L98
https://github.com/gitpod-io/gitpod/blob/main/components/server/src/github/github-context-parser.ts#L159
https://github.com/gitpod-io/gitpod/blob/main/components/server/src/github/github-context-parser.ts#L242
https://github.com/gitpod-io/gitpod/blob/main/components/server/src/github/github-context-parser.ts#L302
https://github.com/gitpod-io/gitpod/blob/main/components/server/src/github/github-context-parser.ts#L360

It's worth changing to check result?.data?.repository for null.

Also, it seems like GH API doesn't consistently return same in such cases. If you try again on the PR mentioned above, it's reports as expected.

[jankeromnes]

It's worth changing to check result?.data?.repository for null.

Aha, good idea! 🎯

Also, it seems like GH API doesn't consistently return same in such cases. If you try again on the PR mentioned above, it's reports as expected.

Yes, as @kylos101 reported, this problem was only temporary:

I think it was just taking Github a long time to restore? Works now, ~26 minutes later.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.