Automate release process via Changesets (#3915)

Co-authored-by: Francisco <fg@frang.io>

scripts/release/workflow/state.js

@@ -0,0 +1,104 @@
+const { readPreState } = require('@changesets/pre');
+const { default: readChangesets } = require('@changesets/read');
+const { join } = require('path');
+const { version } = require(join(__dirname, '../../../package.json'));
+
+module.exports = async ({ github, context, core }) => {
+  const state = await getState({ github, context, core });
+
+  function setOutput(key, value) {
+    core.info(`State ${key} = ${value}`);
+    core.setOutput(key, value);
+  }
+
+  // Jobs to trigger
+  setOutput('start', shouldRunStart(state));
+  setOutput('promote', shouldRunPromote(state));
+  setOutput('changesets', shouldRunChangesets(state));
+  setOutput('publish', shouldRunPublish(state));
+  setOutput('merge', shouldRunMerge(state));
+
+  // Global Variables
+  setOutput('is_prerelease', state.prerelease);
+};
+
+function shouldRunStart({ isMaster, isWorkflowDispatch, botRun }) {
+  return isMaster && isWorkflowDispatch && !botRun;
+}
+
+function shouldRunPromote({ isReleaseBranch, isWorkflowDispatch, botRun }) {
+  return isReleaseBranch && isWorkflowDispatch && !botRun;
+}
+
+function shouldRunChangesets({ isReleaseBranch, isPush, isWorkflowDispatch, botRun }) {
+  return (isReleaseBranch && isPush) || (isReleaseBranch && isWorkflowDispatch && botRun);
+}
+
+function shouldRunPublish({ isReleaseBranch, isPush, hasPendingChangesets }) {
+  return isReleaseBranch && isPush && !hasPendingChangesets;
+}
+
+function shouldRunMerge({
+  isReleaseBranch,
+  isPush,
+  prerelease,
+  isCurrentFinalVersion,
+  hasPendingChangesets,
+  prBackExists,
+}) {
+  return isReleaseBranch && isPush && !prerelease && isCurrentFinalVersion && !hasPendingChangesets && prBackExists;
+}
+
+async function getState({ github, context, core }) {
+  // Variables not in the context
+  const refName = process.env.GITHUB_REF_NAME;
+  const botRun = process.env.TRIGGERING_ACTOR === 'github-actions[bot]';
+
+  const { changesets, preState } = await readChangesetState();
+
+  // Static vars
+  const state = {
+    refName,
+    hasPendingChangesets: changesets.length > 0,
+    prerelease: preState?.mode === 'pre',
+    isMaster: refName === 'master',
+    isReleaseBranch: refName.startsWith('release-v'),
+    isWorkflowDispatch: context.eventName === 'workflow_dispatch',
+    isPush: context.eventName === 'push',
+    isCurrentFinalVersion: !version.includes('-rc.'),
+    botRun,
+  };
+
+  // Async vars
+  const { data: prs } = await github.rest.pulls.list({
+    owner: context.repo.owner,
+    repo: context.repo.repo,
+    head: `${context.repo.owner}:merge/${state.refName}`,
+    base: 'master',
+    state: 'open',
+  });
+
+  state.prBackExists = prs.length === 0;
+
+  // Log every state value in debug mode
+  if (core.isDebug()) for (const [key, value] of Object.entries(state)) core.debug(`${key}: ${value}`);
+
+  return state;
+}
+
+// From https://github.com/changesets/action/blob/v1.4.1/src/readChangesetState.ts
+async function readChangesetState(cwd = process.cwd()) {
+  const preState = await readPreState(cwd);
+  const isInPreMode = preState !== undefined && preState.mode === 'pre';
+
+  let changesets = await readChangesets(cwd);
+
+  if (isInPreMode) {
+    changesets = changesets.filter(x => !preState.changesets.includes(x.id));
+  }
+
+  return {
+    preState: isInPreMode ? preState : undefined,
+    changesets,
+  };
+}