[barredterra]

Closes #1017

Problem

For large releases, the success step can fail with 502 Bad Gateway or 504 from POST /graphql. The release and the tag already exist at that point, so no comments are posted and the next run hides the failure.

GitHub stops a GraphQL request after about 10 seconds (see #1017 (comment)). One getAssociatedPRs query asks for 100 commits × associatedPullRequests(first: 100) with all PR fields. Some of these fields are expensive (mergeable, changedFiles, commits.totalCount). The cost grows with the number of PRs for each commit. On backport branches, one commit can link to many PRs.

Measured on a public repository with a backport branch:

Query	Result
100 commits, all PR fields (current)	502 / 504 after ~11 s, also when it runs alone
25 commits, all PR fields	200, ~10 s
100 commits, PR numbers only	200, ~5 s: 1,890 links, but only 64 unique PRs

Thus, smaller chunks alone do not fix the problem. The same PR is loaded again for each commit that links to it.

Fix

Load the associated PRs in two steps:

1. Get only the PR numbers for each commit (50 commits per query).
2. Remove duplicates, then load the full PR fields with the existing buildRelatedIssuesQuery (10 PRs per query).

Other changes:

• inChunks runs the chunks one after another, not in parallel.
• Related issues are also loaded 10 per query, because they use the same PR fields.
• The issue object for successCommentCondition keeps the same fields.
• The pagination of associatedPullRequests used an undefined variable (response). This is fixed.

Result on 200 commits of the same backport branch: 4 number queries (max 3.2 s) and 8 detail queries for 73 unique PRs (max 1.8 s). All return 200.

Tests

• New test: 120 commits that all link to the same PR. It checks that the numbers are loaded in 3 sequential queries and the PR details in 1 query. It fails on the old code.
• The "multipaged associatedPRs" test did not test pagination: its second mock used overwriteRoutes: true and replaced the first mock. It now checks that a PR from the second page gets a comment.
• Other tests get one more mock for the PR details query.