git: abstract landing session over session

Author: joyeecheung

components/git/git-node-land

@@ -2,15 +2,11 @@
 
 const getMetadata = require('../metadata');
 const CLI = require('../../lib/cli');
-const cli = new CLI(process.stderr);
 const Request = require('../../lib/request');
-const req = new Request();
 const {
-  runPromise, runAsync, runSync, forceRunAsync
+  runPromise
 } = require('../../lib/run');
-const Session = require('../../lib/landing_session');
-const dir = process.cwd();
-const args = process.argv.slice(2);
+const LandingSession = require('../../lib/landing_session');
 
 const START = 'START';
 const APPLY = 'APPLY';
@@ -28,9 +24,15 @@ const states = [
   [ABORT, (args) => args[0] === '--abort']
 ];
 
+const cli = new CLI(process.stderr);
+const req = new Request();
+const dir = process.cwd();
+const args = process.argv.slice(2);
+
 const result = states.filter(([state, pred]) => pred(args));
 if (result.length) {
-  runPromise(main(result[0][0], args).catch((err) => {
+  const state = result[0][0];
+  runPromise(main(state, args).catch((err) => {
     if (cli.spinner.enabled) {
       cli.spinner.fail();
     }
@@ -42,14 +44,13 @@ if (result.length) {
 }
 
 async function main(state, args) {
-  let session;
+  let session = new LandingSession(cli, req, dir);
 
   try {
-    session = Session.restore(dir);
+    session.restore();
   } catch (err) { // JSON error?
     if (state === ABORT) {
-      session = new Session(dir);
-      await abort(session);
+      await session.abort();
       return;
     }
     cli.warn(
@@ -66,246 +67,19 @@ async function main(state, args) {
       cli.log('run `git node land --abort` before starting a new session');
       return;
     }
-    session = new Session(dir, parseInt(args[0]));
-    await start(session);
+    session = new LandingSession(cli, req, dir, parseInt(args[0]));
+    const { repo, owner, prid } = session;
+    const metadata = await getMetadata({ repo, owner, prid }, cli);
+    return session.start(metadata);
   } else if (state === APPLY) {
-    await apply(session);
+    return session.apply();
   } else if (state === AMEND) {
-    await amend(session);
+    return session.amend();
   } else if (state === FINAL) {
-    await final(session);
+    return session.final();
   } else if (state === ABORT) {
-    await abort(session);
+    return session.abort();
   } else if (state === CONTINUE) {
-    await continueSession(session);
-  }
-}
-
-async function start(session) {
-  session.start();
-  const { repo, owner, prid } = session;
-  const result = await getMetadata({ repo, owner, prid }, cli);
-
-  const status = result.status ? 'should be ready' : 'is not ready';
-  const response = await cli.prompt(
-    `This PR ${status} to land, do you want to continue?`);
-  if (response) {
-    session.saveMetadata(result);
-    session.startApplying();
-    return apply(session);
-  } else {
-    await abort(session);
-    process.exit();
-  }
-}
-
-function getNotYetPushedCommits(session, verbose) {
-  const upstream = session.upstream;
-  const branch = session.branch;
-  var revs;
-  if (verbose) {
-    revs = runSync('git',
-      ['log', '--oneline', `${upstream}/${branch}...HEAD`]);
-  } else {
-    revs = runSync('git', ['rev-list', `${upstream}/${branch}...HEAD`]);
-  }
-
-  if (!revs.trim()) {
-    return [];
-  }
-  return revs.trim().split('\n');
-}
-
-async function tryAbortAm(session, cli) {
-  if (session.amInProgress()) {
-    const shouldAbortAm = await cli.prompt(
-      'Abort previous git am sessions?');
-    if (shouldAbortAm) {
-      await forceRunAsync('git', ['am', '--abort']);
-      cli.ok('Aborted previous git am sessions');
-    }
-  } else {
-    cli.ok('No git am in progress');
-  }
-}
-
-async function tryAbortRebase(session, cli) {
-  if (session.rebaseInProgress()) {
-    const shouldAbortRebase = await cli.prompt(
-      'Abort previous git rebase sessions?');
-    if (shouldAbortRebase) {
-      await forceRunAsync('git', ['rebase', '--abort']);
-      cli.ok('Aborted previous git rebase sessions');
-    }
-  } else {
-    cli.ok('No git rebase in progress');
-  }
-}
-
-async function tryResetHead(session, cli) {
-  const branch = `${session.upstream}/${session.branch}`;
-  cli.startSpinner(`Bringing ${branch} up to date`);
-  await runAsync('git',
-    ['fetch', session.upstream, session.branch]);
-  cli.stopSpinner(`${branch} is now up-to-date`);
-  const notYetPushed = getNotYetPushedCommits(session, true);
-  if (notYetPushed.length) {
-    const branch = `${session.upstream}/${session.branch}`;
-    cli.log(`Found strayed commits in ${branch}:\n` +
-      ` - ${notYetPushed.join('\n - ')}`);
-    const shouldReset = await cli.prompt(`Reset to ${branch}?`);
-    if (shouldReset) {
-      await runAsync('git', ['reset', '--hard', branch]);
-      cli.ok(`Reset to ${branch}`);
-    }
-  }
-}
-
-async function tryResetBranch(session, cli) {
-  await tryAbortAm(session, cli);
-  await tryAbortRebase(session, cli);
-
-  const branch = `${session.upstream}/${session.branch}`;
-  const shouldResetHead = await cli.prompt(
-    `Do you want to try reset the branch to ${branch}?`);
-  if (shouldResetHead) {
-    await tryResetHead(session, cli);
-  }
-}
-
-async function abort(session) {
-  session.abort();
-  await tryResetBranch(session, cli);
-  cli.log(`Aborted \`git node land\` session in ${session.ncuDir}`);
-}
-
-async function apply(session) {
-  if (!session.readyToApply()) {
-    cli.warn('This session can not proceed to apply patches, ' +
-      'run `git node land --abort`');
-    return;
-  }
-
-  await tryResetBranch(session, cli);
-
-  const { repo, owner, prid } = session;
-  // TODO: restore previously downloaded patches
-  cli.startSpinner(`Downloading patch for ${prid}`);
-  const patch = await req.promise({
-    url: `https://github.com/${owner}/${repo}/pull/${prid}.patch`
-  });
-  session.savePatch(patch);
-  cli.stopSpinner(`Downloaded patch to ${session.patchPath}`);
-
-  // TODO: check that patches downloaded match metadata.commits
-  await runAsync('git', ['am', '--whitespace=fix', session.patchPath]);
-  cli.ok('Patches applied');
-
-  session.startAmending();
-  if (/Subject: \[PATCH\]/.test(patch)) {
-    const shouldAmend = await cli.prompt(
-      'There is only one commit in this PR.\n' +
-      'do you want to amend the commit message?');
-    if (shouldAmend) {
-      const canFinal = await amend(session);
-      if (canFinal) {
-        return final(session);
-      }
-    }
-  } else {
-    const re = /Subject: \[PATCH 1\/(\d+)\]/;
-    const match = patch.match(re);
-    if (!match) {
-      cli.warn('Cannot get number of commits in the patch. ' +
-        'It seems to be malformed');
-      return;
-    }
-    const upstream = session.upstream;
-    const branch = session.branch;
-    cli.log(
-      `There are ${match[1]} commits in the PR.\n` +
-      `Please run \`git rebase ${upstream}/${branch} -i\` ` +
-      'and use `git node land --amend` to amend the commit messages');
-    // TODO: do git rebase automatically?
-  }
-}
-
-async function amend(session) {
-  if (!session.readyToAmend()) {
-    cli.warn('Not yet ready to amend, run `git node land --abort`');
-    return;
-  }
-
-  const rev = runSync('git', ['rev-parse', 'HEAD']);
-  const original = runSync('git', ['show', 'HEAD', '-s', '--format=%B']).trim();
-  const metadata = session.metadata.trim().split('\n');
-  const amended = original.split('\n');
-  if (amended[amended.length - 1] !== '') {
-    amended.push('');
-  }
-
-  for (const line of metadata) {
-    if (original.includes(line)) {
-      if (line) {
-        cli.warn(`Found ${line}, skipping..`);
-      }
-    } else {
-      amended.push(line);
-    }
-  }
-
-  const message = amended.join('\n') + '\n';
-  const messageFile = session.saveMessage(rev, message);
-  cli.separator('New Message');
-  cli.log(message.trim());
-  cli.separator();
-  const takeMessage = await cli.prompt('Use this message?');
-  if (takeMessage) {
-    await runAsync('git', ['commit', '--amend', '-F', messageFile]);
-    // session.markAsAmended(rev);
-    return true;
-  }
-
-  cli.log(`Please manually edit ${messageFile}, then run\n` +
-    `\`git commit --amend -F ${messageFile}\` to finish amending the message`);
-  return false;
-};
-
-async function final(session) {
-  if (!session.readyToFinal()) {  // check git rebase/am has been done
-    cli.warn('Not yet ready to final');
-    return;
-  }
-  const upstream = session.upstream;
-  const branch = session.branch;
-  const notYetPushed = getNotYetPushedCommits(session);
-  const notYetPushedVerbose = getNotYetPushedCommits(session, true);
-  await runAsync('core-validate-commit', notYetPushed);
-  cli.separator();
-  cli.log('The following commits are ready to be pushed to ' +
-    `${upstream}/${branch}`);
-  cli.log(`- ${notYetPushedVerbose.join('\n- ')}`);
-  cli.separator();
-  cli.log(`run \`git push ${upstream} ${branch}\` to finish landing`);
-  const shouldClean = await cli.prompt('Clean up generated temporary files?');
-  if (shouldClean) {
-    session.cleanFiles();
-  }
-}
-
-async function continueSession(session) {
-  if (session.readyToFinal()) {
-    return final(session);
-  }
-  if (session.readyToAmend()) {
-    return amend(session);
-  }
-  if (session.readyToApply()) {
-    return apply(session);
-  }
-  if (session.hasStarted()) {
-    return apply(session);
+    return session.continue();
   }
-  cli.log(
-    'Please run `git node land <PRID> to start a landing session`');
 }