Scala Steward attempting to raise PRs for group branches that already have PRs about scala-steward

[rtyley]

This appears to because the head string used by listPullRequests() (which is supposed to be finding us the existing PRs) is not being accepted by the GitHub API.

We're sending head=guardian/facia-scala-client%3Aupdate/aws, which is returning 0 results. On the other hand, if I manually make the request to the GitHub API, with head=update/aws, I get results:

scala-steward/modules/core/src/main/scala/org/scalasteward/core/forge/github/Url.scala

Lines 31 to 33 in c317b87

	def listPullRequests(repo: Repo, head: String, base: Branch): Uri =
	pulls(repo)
	.withQueryParam("head", head)

% curl --silent "https://api.github.com/repos/guardian/facia-scala-client/pulls?head=guardian/facia-scala-client%3Aupdate/aws&base=main&state=all" | head
[

]
% curl --silent "https://api.github.com/repos/guardian/facia-scala-client/pulls?head=update/aws&base=main&state=all" | head
[
  {
    "url": "https://api.github.com/repos/guardian/facia-scala-client/pulls/307",
    "id": 1747950527,
    "node_id": "PR_kwDOATw1z85oL5u_",
    "html_url": "https://github.com/guardian/facia-scala-client/pull/307",
    "diff_url": "https://github.com/guardian/facia-scala-client/pull/307.diff",
    "patch_url": "https://github.com/guardian/facia-scala-client/pull/307.patch",
    "issue_url": "https://api.github.com/repos/guardian/facia-scala-client/issues/307",
    "number": 307,

The documentation for the API endpoint says:

head string
Filter pulls by head user or head organization and branch name in the format of user:ref-name or organization:ref-name. For example: github:new-script-format or octocat:test-branch.

There's nothing in there that to suggest that we can include the repo name as well (ie. guardian/facia-scala-client%3A)...

[rtyley]

The head name is constructed in listingBranch(), which is code that does not appear to have changed much recently...

scala-steward/modules/core/src/main/scala/org/scalasteward/core/forge/package.scala

Lines 28 to 35 in 1005ebe

	def listingBranch(forgeType: ForgeType, fork: Repo, updateBranch: Branch): String =
	forgeType match {
	case GitHub =>
	s"${fork.owner}/${fork.repo}:${updateBranch.name}"
	case GitLab | Bitbucket | BitbucketServer | AzureRepos | Gitea =>
	updateBranch.name
	}

The repo name does seem redundant, as the path in the REST API request already contains /repos/{owner}/{repo}/pulls, giving the original repo, and GitHub only allows one fork of a repo per organisation or user, so including the user/org in the prefix should be sufficient to uniquely identify a fork.

It does look as though, in the past with #649 in 2019, the Scala Steward code deliberately did use the repo name in the head parameter, so it probably worked at that point.

[adamw]

Thanks for investigating this! I'm getting tens of emails every night for a couple of days now, because of failed steward actions. And I see that even a PR is there ❤️