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JavaScript
at master
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234const { classify } = require('../supportedBranches.js')const { postReview, dismissReviews } = require('./reviews.js')const reviewKey = 'prepare'const supportedSystems = require('./supportedSystems.js')
module.exports = async ({ github, context, core, dry }) => { const pull_number = context.payload.pull_request.number
for (const retryInterval of [5, 10, 20, 40, 80]) { core.info('Checking whether the pull request can be merged...') const prInfo = ( await github.rest.pulls.get({ ...context.repo, pull_number, }) ).data
if (prInfo.state !== 'open') throw new Error('PR is not open anymore.')
if (prInfo.mergeable == null) { core.info( `GitHub is still computing whether this PR can be merged, waiting ${retryInterval} seconds before trying again...`, ) await new Promise((resolve) => setTimeout(resolve, retryInterval * 1000)) continue }
const { base, head } = prInfo
const baseClassification = classify(base.ref) core.setOutput('base', baseClassification) console.log('base classification:', baseClassification)
const headClassification = base.repo.full_name === head.repo.full_name ? classify(head.ref) : // PRs from forks are always considered WIP. { type: ['wip'] } core.setOutput('head', headClassification) console.log('head classification:', headClassification)
if (baseClassification.type.includes('channel')) { const { stable, version } = baseClassification const correctBranch = stable ? `release-${version}` : 'master' const body = [ 'The `nixos-*` and `nixpkgs-*` branches are pushed to by the channel release script and should not be merged into directly.', '', `Please target \`${correctBranch}\` instead.`, ].join('\n')
await postReview({ github, context, core, dry, body, reviewKey })
throw new Error('The PR targets a channel branch.') }
if (headClassification.type.includes('wip')) { // In the following, we look at the git history to determine the base branch that // this Pull Request branched off of. This is *supposed* to be the branch that it // merges into, but humans make mistakes. Once that happens we want to error out as // early as possible.
// To determine the "real base", we are looking at the merge-base of primary development // branches and the head of the PR. The merge-base which results in the least number of // commits between that base and head is the real base. We can query for this via GitHub's // REST API. There can be multiple candidates for the real base with the same number of // commits. In this case we pick the "best" candidate by a fixed ordering of branches, // as defined in ci/supportedBranches.js. // // These requests take a while, when comparing against the wrong release - they need // to look at way more than 10k commits in that case. Thus, we try to minimize the // number of requests across releases: // - First, we look at the primary development branches only: master and release-xx.yy. // The branch with the fewest commits gives us the release this PR belongs to. // - We then compare this number against the relevant staging branches for this release // to find the exact branch that this belongs to.
// All potential development branches const branches = ( await github.paginate(github.rest.repos.listBranches, { ...context.repo, per_page: 100, }) ).map(({ name }) => classify(name))
// All stable primary development branches from latest to oldest. const releases = branches .filter(({ stable, type }) => type.includes('primary') && stable) .sort((a, b) => b.version.localeCompare(a.version))
async function mergeBase({ branch, order, version }) { const { data } = await github.rest.repos.compareCommitsWithBasehead({ ...context.repo, basehead: `${branch}...${head.sha}`, // Pagination for this endpoint is about the commits listed, which we don't care about. per_page: 1, // Taking the second page skips the list of files of this changeset. page: 2, }) return { branch, order, version, commits: data.total_commits, sha: data.merge_base_commit.sha, } }
// Multiple branches can be OK at the same time, if the PR was created of a merge-base, // thus storing as array. let candidates = [await mergeBase(classify('master'))] for (const release of releases) { const nextCandidate = await mergeBase(release) if (candidates[0].commits === nextCandidate.commits) candidates.push(nextCandidate) if (candidates[0].commits > nextCandidate.commits) candidates = [nextCandidate] // The number 10000 is principally arbitrary, but the GitHub API returns this value // when the number of commits exceeds it in reality. The difference between two stable releases // is certainly more than 10k commits, thus this works for us as well: If we're targeting // a wrong release, the number *will* be 10000. if (candidates[0].commits < 10000) break }
core.info(`This PR is for NixOS ${candidates[0].version}.`)
// Secondary development branches for the selected version only. const secondary = branches.filter( ({ branch, type, version }) => type.includes('secondary') && version === candidates[0].version, )
// Make sure that we always check the current target as well, even if its a WIP branch. secondary.push(classify(base.ref))
for (const branch of secondary) { const nextCandidate = await mergeBase(branch) if (candidates[0].commits === nextCandidate.commits) candidates.push(nextCandidate) if (candidates[0].commits > nextCandidate.commits) candidates = [nextCandidate] }
// If the current branch is among the candidates, this is always better than any other, // thus sorting at -1. candidates = candidates .map((candidate) => candidate.branch === base.ref ? { ...candidate, order: -1 } : candidate, ) .sort((a, b) => a.order - b.order)
const best = candidates.at(0)
core.info('The base branches for this PR are:') core.info(`github: ${base.ref}`) core.info( `candidates: ${candidates.map(({ branch }) => branch).join(',')}`, ) core.info(`best candidate: ${best.branch}`)
if (best.branch !== base.ref) { const current = await mergeBase(classify(base.ref)) const body = [ `The PR's base branch is set to \`${current.branch}\`, but ${current.commits === 10000 ? 'at least 10000' : current.commits - best.commits} commits from the \`${best.branch}\` branch are included. Make sure you know the [right base branch for your changes](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#branch-conventions), then:`, `- If the changes should go to the \`${best.branch}\` branch, [change the base branch](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/changing-the-base-branch-of-a-pull-request).`, `- If the changes should go to the \`${current.branch}\` branch, rebase your PR onto the correct merge-base:`, ' ```bash', ` # git rebase --onto $(git merge-base upstream/${current.branch} HEAD) $(git merge-base upstream/${best.branch} HEAD)`, ` git rebase --onto ${current.sha} ${best.sha}`, ` git push --force-with-lease`, ' ```', ].join('\n')
await postReview({ github, context, core, dry, body, reviewKey })
throw new Error(`The PR contains commits from a different base.`) } }
await dismissReviews({ github, context, core, dry, reviewKey })
let mergedSha, targetSha
if (prInfo.mergeable) { core.info('The PR can be merged.')
mergedSha = prInfo.merge_commit_sha targetSha = ( await github.rest.repos.getCommit({ ...context.repo, ref: prInfo.merge_commit_sha, }) ).data.parents[0].sha } else { core.warning('The PR has a merge conflict.')
mergedSha = head.sha targetSha = ( await github.rest.repos.compareCommitsWithBasehead({ ...context.repo, basehead: `${base.sha}...${head.sha}`, }) ).data.merge_base_commit.sha }
core.info( `Checking the commits:\nmerged: ${mergedSha}\ntarget: ${targetSha}`, ) core.setOutput('mergedSha', mergedSha) core.setOutput('targetSha', targetSha)
const systems = await supportedSystems({ github, context, targetSha }) core.setOutput('systems', systems)
const files = ( await github.paginate(github.rest.pulls.listFiles, { ...context.repo, pull_number: context.payload.pull_request.number, per_page: 100, }) ).map((file) => file.filename)
const touched = [] if (files.includes('ci/pinned.json')) touched.push('pinned') core.setOutput('touched', touched)
return } throw new Error( "Not retrying anymore. It's likely that GitHub is having internal issues: check https://www.githubstatus.com.", )}