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// @ts-check
const { classify } = require('../supportedBranches.js')
const { postReview, dismissReviews } = require('./reviews.js')
const reviewKey = 'prepare'
/**
* Prepares a PR for CI by checking mergeability and branch targeting.
*
* Outputs:
* - base: base branch classification
* - head: head branch classification
* - mergedSha: the merge commit SHA (or head SHA if conflict)
* - targetSha: the target comparison SHA
*
* @param {{
* github: InstanceType<import('@actions/github/lib/utils').GitHub>,
* context: import('@actions/github/lib/context').Context,
* core: import('@actions/core'),
* dry?: boolean,
* }} PrepareProps
*/
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 mergeability, waiting ${retryInterval}s...`,
)
await new Promise((resolve) => setTimeout(resolve, retryInterval * 1000))
continue
}
const { base, head } = prInfo
const baseClassification = classify(base.ref)
core.setOutput('base', baseClassification)
console.log('base classification:', baseClassification)
const headClassification =
base.repo.full_name === head.repo.full_name
? classify(head.ref)
: { type: ['wip'] }
core.setOutput('head', headClassification)
console.log('head classification:', headClassification)
// Warn if targeting a release branch with a non-backport/fix branch
if (
baseClassification.stable &&
baseClassification.type.includes('primary')
) {
const headPrefix = head.ref.split('-')[0]
if (!['backport', 'fix', 'revert'].includes(headPrefix)) {
core.warning(
`This PR targets release branch \`${base.ref}\`. ` +
'New features should typically target \`master\`.',
)
}
}
// Check base branch targeting
if (headClassification.type.includes('wip')) {
// Determine the best base branch candidate
const branches = (
await github.paginate(github.rest.repos.listBranches, {
...context.repo,
per_page: 100,
})
).map(({ name }) => classify(name))
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}`,
per_page: 1,
page: 2,
})
return {
branch,
order,
version,
commits: data.total_commits,
sha: data.merge_base_commit.sha,
}
}
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]
if (candidates[0].commits < 10000) break
}
const best = candidates.sort((a, b) => a.order - b.order).at(0)
core.info(`Best base branch candidate: ${best.branch}`)
if (best.branch !== base.ref) {
const current = await mergeBase(classify(base.ref))
const body = [
`This PR targets \`${current.branch}\`, but based on the commit history ` +
`\`${best.branch}\` appears to be a better fit ` +
`(${current.commits - best.commits} fewer commits ahead).`,
'',
`If this is intentional, you can ignore this message. Otherwise:`,
`- [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) to \`${best.branch}\`.`,
].join('\n')
await postReview({ github, context, core, dry, body, reviewKey })
core.warning(`PR may target the wrong base branch.`)
} else {
await dismissReviews({ github, context, core, dry, reviewKey })
}
} else {
await dismissReviews({ github, context, core, dry, reviewKey })
}
let mergedSha, targetSha
if (prInfo.mergeable) {
core.info('The PR can be merged.')
mergedSha = prInfo.merge_commit_sha
targetSha = (
await github.rest.repos.getCommit({
...context.repo,
ref: prInfo.merge_commit_sha,
})
).data.parents[0].sha
} else {
core.warning('The PR has a merge conflict.')
mergedSha = head.sha
targetSha = (
await github.rest.repos.compareCommitsWithBasehead({
...context.repo,
basehead: `${base.sha}...${head.sha}`,
})
).data.merge_base_commit.sha
}
core.info(`merged: ${mergedSha}\ntarget: ${targetSha}`)
core.setOutput('mergedSha', mergedSha)
core.setOutput('targetSha', targetSha)
// Detect touched CI-relevant files
const files = (
await github.paginate(github.rest.pulls.listFiles, {
...context.repo,
pull_number,
per_page: 100,
})
).map((file) => file.filename)
const touched = []
if (files.some((f) => f.startsWith('ci/'))) touched.push('ci')
if (files.includes('ci/pinned.json')) touched.push('pinned')
if (files.some((f) => f.startsWith('.github/'))) touched.push('github')
core.setOutput('touched', touched)
return
}
throw new Error(
'Timed out waiting for GitHub to compute mergeability. Check https://www.githubstatus.com.',
)
}
|
