CircleCI: Don't tag hotfix releases with latest during publish job,…

… allow prerelease tags (#1086)

Summary:
Currently, when we `npm publish --workspaces` on tag creation, NPM implicitly tags with "latest". This is fine in the regular release flow, but when we release a hotfix (a patch release on an old minor, from a release branch) the tag is incorrect.

This causes issues that some folks notice within minutes: #931, #1057. Currently, it has to be manually corrected using `dist-tag` on each package after publishing.

This adds some logic in CircleCI to automatically tag with `latest` explicitly *only if* the tag is present on `main`, and not on any release branch (of the form `0.79.x`). OTOH, if the release looks like a hotfix (present on a release branch but *not* on `main`) we tag with the release branch name. There is no way in NPM not to have any dist-tag, so specifying *something* is the only way to prevent it assuming `latest`.

If the release is ambiguous (edge case: we go back and tag a common ancestor of `main` and `0.123.x` with `v0.123.0-alpha`) the publish aborts.

Pull Request resolved: #1086

Test Plan:
- Tested (after many iterations!) at my fork https://github.com/robhogan/metro, eg https://app.circleci.com/pipelines/github/robhogan/metro/74/workflows/5a375202-5863-43fd-b633-4a983b0ed4b8/jobs/264
 - I'm about to run a hotfix release to pull some bug fixes back for RN 0.72, so that'll be the first "live" test.

Reviewed By: huntie

Differential Revision: D49461403

Pulled By: robhogan

fbshipit-source-id: 26fd37d90ccae9d2125e9ef1cc8ba538ee6beb85

.circleci/config.yml

@@ -110,7 +110,9 @@ jobs:
       - checkout
       - yarn_install
       - run: echo "//registry.npmjs.org/:_authToken=$NPM_TOKEN" >> ~/.npmrc
-      - run: npm run publish
+      - run:
+          name: Infer dist-tag and run npm run publish
+          command: ./.circleci/scripts/publish.sh
       - run: rm ~/.npmrc
 
 workflows:
@@ -134,4 +136,4 @@ workflows:
             branches:
               ignore: /.*/
             tags:
-              only: /v[0-9]+(\.[0-9]+)*/
+              only: /v\d+(\.\d+){2}(-.*)?/

.circleci/scripts/publish.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Reduce a semver tag name to a Metro's release branch naming convention, eg v0.1.2-alpha.3 -> 0.1.x
+RELEASE_BRANCH=$(echo "$CIRCLE_TAG" | awk -F. '{print substr($1, 2) "." $2 ".x"}')
+
+# Does a release branch contain this tag (hotfix workflow)
+TAG_ON_RELEASE_BRANCH=$(git branch -a --contains "$CIRCLE_TAG" | grep -cFx "  remotes/origin/$RELEASE_BRANCH" || true)
+echo "Tag is on release branch $RELEASE_BRANCH: $TAG_ON_RELEASE_BRANCH"
+
+# Does main contain this tag (regular release workflow)
+TAG_ON_MAIN=$(git branch -a --contains "$CIRCLE_TAG" | grep -cFx '  remotes/origin/main' || true)
+echo "Tag is on main branch: $TAG_ON_MAIN"
+
+if [ $TAG_ON_RELEASE_BRANCH -eq $TAG_ON_MAIN ]; then
+    echo "Could not determine whether this tag is 'latest' or a hotfix. Aborting."
+    exit 1
+fi
+
+NPM_TAG="latest"
+[ "$TAG_ON_RELEASE_BRANCH" -eq 1 ] && NPM_TAG=$RELEASE_BRANCH
+echo "Publishing with --tag=$NPM_TAG"
+
+npm run publish --tag="$NPM_TAG"