Add --commit param to release scripts (#20703)

Alternative to `--build`. Uses same logic as sizebot and www
sync script.

Immediate motivation is I want sizebot to use the
`download-experimental-build` command in CI. Will do that next.

scripts/release/download-experimental-build.js

@@ -19,7 +19,7 @@ const run = async () => {
   try {
     addDefaultParamValue('-r', '--releaseChannel', 'experimental');
 
-    const params = parseParams();
+    const params = await parseParams();
     params.cwd = join(__dirname, '..', '..');
     params.packages = await getPublicPackages(true);
 

scripts/release/get-build-id-for-commit.js

@@ -0,0 +1,34 @@
+'use strict';
+
+const fetch = require('node-fetch');
+
+async function getBuildIdForCommit(sha) {
+  let ciBuildId = null;
+  const statusesResponse = await fetch(
+    `https://api.github.com/repos/facebook/react/commits/${sha}/status`
+  );
+
+  if (!statusesResponse.ok) {
+    throw Error('Could not find commit for: ' + sha);
+  }
+
+  const {statuses, state} = await statusesResponse.json();
+  if (state === 'failure') {
+    throw new Error(`Base commit is broken: ${sha}`);
+  }
+  for (let i = 0; i < statuses.length; i++) {
+    const status = statuses[i];
+    if (status.context === `ci/circleci: process_artifacts_combined`) {
+      if (status.state === 'success') {
+        ciBuildId = /\/facebook\/react\/([0-9]+)/.exec(status.target_url)[1];
+        break;
+      }
+      if (status.state === 'pending') {
+        throw new Error(`Build job for base commit is still pending: ${sha}`);
+      }
+    }
+  }
+  return ciBuildId;
+}
+
+module.exports = getBuildIdForCommit;

scripts/release/prepare-release-from-ci.js

@@ -15,7 +15,7 @@ const testTracingFixture = require('./shared-commands/test-tracing-fixture');
 
 const run = async () => {
   try {
-    const params = parseParams();
+    const params = await parseParams();
     params.cwd = join(__dirname, '..', '..');
 
     if (!params.build) {

scripts/release/shared-commands/parse-params.js

@@ -3,13 +3,22 @@
 'use strict';
 
 const commandLineArgs = require('command-line-args');
+const getBuildIdForCommit = require('../get-build-id-for-commit');
 
 const paramDefinitions = [
   {
     name: 'build',
     type: Number,
     description:
       'Circle CI build identifier (e.g. https://circleci.com/gh/facebook/react/<build>)',
+    defaultValue: null,
+  },
+  {
+    name: 'commit',
+    type: String,
+    description:
+      'GitHub commit SHA. When provided, automatically finds corresponding CI build.',
+    defaultValue: null,
   },
   {
     name: 'skipTests',
@@ -25,9 +34,29 @@ const paramDefinitions = [
   },
 ];
 
-module.exports = () => {
+module.exports = async () => {
   const params = commandLineArgs(paramDefinitions);
 
+  if (params.build !== null) {
+    if (params.commit !== null) {
+      console.error(
+        '`build` and `commmit` params are mutually exclusive. Choose one or the other.`'
+      );
+      process.exit(1);
+    }
+  } else {
+    if (params.commit === null) {
+      console.error('Must provide either `build` or `commit`.');
+      process.exit(1);
+    }
+    try {
+      params.build = await getBuildIdForCommit(params.commit);
+    } catch (error) {
+      console.error(error.message);
+      process.exit(1);
+    }
+  }
+
   const channel = params.releaseChannel;
   if (channel !== 'experimental' && channel !== 'stable') {
     console.error(