Set the last three digit of the AMP version to be the number of cherr…

…y-picks in the branch (#27848)

build-system/common/git.js

@@ -169,12 +169,36 @@ function gitCommitterEmail() {
 }
 
 /**
- * Returns the timestamp of the latest commit on the local branch.
- * @return {number}
+ * Returns list of commit SHAs and their cherry-pick status from master.
+ *
+ * `git cherry <branch>` returns a list of commit SHAs. While the exact
+ * mechanism is too complicated for this comment (run `git help cherry` for a
+ * full explanation), the gist of it is that commits that were cherry-picked
+ * from <branch> are prefixed with '- ', and those that were not are prefixed
+ * with '+ '.
+ *
+ * @return {!Array<{sha: string, isCherryPick: boolean}>}
+ */
+function gitCherryMaster() {
+ return getStdout('git cherry master')
+ .trim()
+ .split('\n')
+ .map((line) => ({
+ isCherryPick: line.substring(0, 2) == '- ',
+ sha: line.substring(2),
+ }));
+}
+
+/**
+ * Returns (UTC) time of a commit on the local branch, in %y%m%d%H%M%S format.
+ *
+ * @param {string} ref a Git reference (commit SHA, branch name, etc.) for the
+ * commit to get the time of.
+ * @return {string}
  */
-function gitCommitFormattedTime() {
+function gitCommitFormattedTime(ref = 'HEAD') {
  return getStdout(
- 'TZ=UTC git log -1 --pretty="%cd" --date=format-local:%y%m%d%H%M%S'
+ `TZ=UTC git log ${ref} -1 --pretty="%cd" --date=format-local:%y%m%d%H%M%S`
  ).trim();
 }
 
@@ -211,6 +235,7 @@ function gitDiffPath(path, commit) {
 module.exports = {
  gitBranchCreationPoint,
  gitBranchName,
+ gitCherryMaster,
  gitCommitFormattedTime,
  gitCommitHash,
  gitCommitterEmail,

build-system/compile/internal-version.js

@@ -16,50 +16,97 @@
 'use strict';
 
 const minimist = require('minimist');
-const {gitCommitFormattedTime} = require('../common/git');
+const {gitCherryMaster, gitCommitFormattedTime} = require('../common/git');
 
 // Allow leading zeros in --version_override, e.g. 0000000000001
 const argv = minimist(process.argv.slice(2), {
  string: ['version_override'],
 });
 
+/**
+ * Generates the AMP version number.
+ *
+ * Version numbers are determined using the following algorithm:
+ * - Count the number (<X>) of cherry-picked commits on this branch that came
+ * from the `master` branch, until reaching `master` or the first commit that
+ * was added directly on this branch (if the current commit is on `master`'s
+ * commit history, or only contains new commits that are not cherry-picked
+ * from `master`, then <X> is 0).
+ * - Find the commit (<C>) before the last cherry-picked commit from the
+ * `master` branch (if the current branch is `master`, or otherwise in
+ * `master`'s commit history, then the current commit is <C>).
+ * - Find the commit time of <C> (<C>.time). Note that commit time might be
+ * different from author time! e.g., commit time might be the time that a PR
+ * was merged into `master`, or a commit was cherry-picked onto the branch;
+ * author time is when the original author of the commit ran the "git commit"
+ * command.
+ * - The version number is <C>.time.format("YYmmDDHHMM", "UTC") + <X> (the
+ * pseudo-code assumes standard `.strftime` formatting, and <X> gets
+ * zero-padded until it is three digits long).
+ * - The maximum number of cherry-picks in a single branch is 999. More than
+ * that will fail to build. This should never happen.
+ *
+ * Examples:
+ * 1. The version number of a release built from the HEAD commit on `master`,
+ * where that HEAD commit was committed on April 25, 2020 2:31 PM EDT would
+ * be `2004251831000`.
+ * - EDT is UTC-4, so the hour value changes from EDT's 14 to UTC's 18.
+ * - The last three digits are 000 as this commit is on `master`.
+ *
+ * 2. The version number of a release built from a local working branch (e.g.,
+ * on a developer's workstation) that was split off from a `master` commit
+ * from May 6, 2021 10:40 AM PDT and has multiple commits that exist only on
+ * local working branch would be `2105061840000`.
+ * - PDT is UTC-7, so the hour value changes from PDT's 10 to UTC's 17.
+ * - The last three digits are 000 as this commit is on a branch that was
+ * split from `master`, and does not have any cherry-picked commits.
+ *
+ * 3. For a release built from a local working branch that was split off from a
+ * `master` commit from November 9, 2021 11:48 PM PST, and then:
+ * - had one commit that was cherry-picked from `master`,
+ * - followed by two commits that were created directly on the branch, the
+ * last of which was commited on November 23, 2021 6:38 PM PST,
+ * - followed by twelve commits that were cherry-picked from `master`, then
+ * its version number would be `2111240238012`.
+ * - The latest twelve commits are cherry-picks from `master`, and the one
+ * before them is not, so our last three digits are set to 012.
+ * - PST is UTC-8, so the hour value changes from PST's 18 to UTC's 2, and
+ * one day is added.
+ *
+ * The version number can be manually overridden by passing --version_override
+ * to the `gulp build`/`gulp dist` command.
+ *
+ * @return {string} AMP version number (always 13 digits long)
+ */
 function getVersion() {
  if (argv.version_override) {
  const version = String(argv.version_override);
- // #27579: What are allowed version strings...?
  if (!/^\d{13}$/.test(version)) {
  throw new Error('--version_override only accepts a 13-digit version');
  }
  return version;
- } else {
- // Generate a consistent version number by using the commit* time of the
- // latest commit on the active branch as the twelve digits. The last,
- // thirteenth digit defaults to 0, but can be changed by setting the
- // --custom_version_mark flag to a different value. This should rarely be
- // used by AMP release engineers.
- //
- // e.g., the version number of a clean (no uncommited changes) tree that was
- // commited on August 1, 2018 at 14:31:11 EDT would be `1808011831110`
- // (notice that due to timezone shift, the hour value changes from EDT's 14
- // to UTC's 18. The last digit is the default value of 0 as
- // --custom_version_mark was not set.)
- //
- // *Commit time is different from author time! Commit time is the time that
- // the PR was merged into master; author time is when the author ran the
- // "git commit" command.
- const lastCommitFormattedTime = gitCommitFormattedTime();
- let lastDigit = 0;
- if (argv.custom_version_mark) {
- lastDigit = parseInt(argv.custom_version_mark, 10);
- if (isNaN(lastDigit) || lastDigit < 0 || lastDigit > 9) {
- throw new Error(
- `--custom_version_mark is set to ${argv.custom_version_mark}, ` +
- 'expected value between 0 and 9!'
- );
- }
+ }
+
+ let numberOfCherryPicks = 0;
+ const commitCherriesInfo = gitCherryMaster().reverse();
+ for (const {isCherryPick} of commitCherriesInfo) {
+ if (!isCherryPick) {
+ break;
  }
- return `${lastCommitFormattedTime}${lastDigit}`;
+ numberOfCherryPicks++;
  }
+ if (numberOfCherryPicks > 999) {
+ throw new Error(
+ `This branch has ${numberOfCherryPicks} cherry-picks, which is more than 999, the maximum allowed number of cherry-picks!`
+ );
+ }
+
+ const lastCommitFormattedTime = gitCommitFormattedTime(
+ `HEAD~${numberOfCherryPicks}`
+ ).slice(0, -2);
+
+ numberOfCherryPicks = String(numberOfCherryPicks).padStart(3, '0');
+ return `${lastCommitFormattedTime}${numberOfCherryPicks}`;
 }
 
 // Used to e.g. references the ads binary from the runtime to get version lock.

build-system/tasks/build.js

@@ -110,7 +110,6 @@ build.flags = {
  core_runtime_only: ' Builds only the core runtime.',
  coverage: ' Adds code coverage instrumentation to JS files using istanbul.',
  version_override: ' Overrides the version written to AMP_CONFIG',
- custom_version_mark: ' Set final digit (0-9) on auto-generated version',
  watch: ' Watches for changes in files, re-builds when detected',
  define_experiment_constant:
  ' Builds runtime with the EXPERIMENT constant set to true',

build-system/tasks/default-task.js

@@ -85,7 +85,6 @@ defaultTask.flags = {
  disable_nailgun:
  " Doesn't use nailgun to invoke closure compiler (much slower)",
  version_override: ' Overrides the version written to AMP_CONFIG',
- custom_version_mark: ' Set final digit (0-9) on auto-generated version',
  host: ' Host to serve the project on. localhost by default.',
  port: ' Port to serve the project on. 8000 by default.',
  define_experiment_constant:

build-system/tasks/dist.js

@@ -463,7 +463,6 @@ dist.flags = {
  type: ' Points sourcemap to fetch files from the correct GitHub tag',
  esm: ' Does not transpile down to ES5',
  version_override: ' Override the version written to AMP_CONFIG',
- custom_version_mark: ' Set final digit (0-9) on auto-generated version',
  watch: ' Watches for changes in files, re-compiles when detected',
  closure_concurrency: ' Sets the number of concurrent invocations of closure',
  debug: ' Outputs the file contents during compilation lifecycles',