Merge pull request #746 from heroku/da/detect-yarn2

Detect Yarn2 and give error message

CHANGELOG.md

@@ -4,6 +4,7 @@
 - Bump rake from 12.3.1 to 12.3.3 ([#742](https://github.com/heroku/heroku-buildpack-nodejs/pull/742))
 - Upgrade Go to 1.14 ([#744](https://github.com/heroku/heroku-buildpack-nodejs/pull/744))
 - Bump `npm ci` usage for installing dependencies to 20% ([#745](https://github.com/heroku/heroku-buildpack-nodejs/pull/745))
+- Detect Yarn 2 usage, produce error message, and fail build (until supported) ([#746](https://github.com/heroku/heroku-buildpack-nodejs/pull/746))
 
 ## v167 (2020-02-06)
 - Make minor upgrades to gems ([#735](https://github.com/heroku/heroku-buildpack-nodejs/pull/735))

README.md

@@ -55,7 +55,7 @@ Having trouble? Dig it? Feature request?
 For local development, you may need the following tools:
 
 - [Docker](https://hub.docker.com/search?type=edition&offering=community)
-- [Go 1.14]((https://golang.org/doc/install#install))
+- [Go 1.14](https://golang.org/doc/install#install)
 - [upx](https://upx.github.io/)
 
 ### Deploying an app with a fork or branch

bin/compile

@@ -52,6 +52,8 @@ source "$BP_DIR/lib/metadata.sh"
 source "$BP_DIR/lib/features.sh"
 # shellcheck source=lib/builddata.sh
 source "$BP_DIR/lib/builddata.sh"
+# shellcheck source=lib/yarn2.sh
+source "$BP_DIR/lib/yarn2.sh"
 
 export PATH="$BUILD_DIR/.heroku/node/bin:$BUILD_DIR/.heroku/yarn/bin":$PATH
 
@@ -85,7 +87,7 @@ trap 'handle_failure' ERR
 meta_init "$CACHE_DIR"
 # Make sure that it's empty and save any previous build's data
 meta_setup
-# the "build-step" key keeps track of where we are in the execution 
+# the "build-step" key keeps track of where we are in the execution
 # so that we can see where failed builds errored
 meta_set "build-step" "init"
 
@@ -99,14 +101,15 @@ meta_set "build-step" "init"
 features_init "nodejs" "$BUILD_DIR" "$CACHE_DIR" "$BP_DIR/features"
 log_initial_state
 generate_uuids
- 
+
 ### Failures that should be caught immediately
 
 fail_dot_heroku "$BUILD_DIR"
 fail_dot_heroku_node "$BUILD_DIR"
 fail_invalid_package_json "$BUILD_DIR"
 fail_multiple_lockfiles "$BUILD_DIR"
 fail_iojs_unsupported "$BUILD_DIR"
+fail_yarn2_unsupported "$YARN" "$BUILD_DIR"
 warn_prebuilt_modules "$BUILD_DIR"
 warn_missing_package_json "$BUILD_DIR"
 

lib/failure.sh

@@ -102,17 +102,43 @@ fail_iojs_unsupported() {
        }
 
        io.js merged back into Nodejs.org in 2015 and has been unsupported
-       for many years. It is likely to contain several large security 
+       for many years. It is likely to contain several large security
        vulnerabilities that have been patched in Node.
 
-       You can update your app to use the official Node.js release by 
+       You can update your app to use the official Node.js release by
        removing the version specfication under \"engines\" in your
        package.json.
        "
     fail
   fi
 }
 
+fail_yarn2_unsupported() {
+  local uses_yarn="$1"
+  local build_dir="$2"
+  local uses_yarn2
+
+  uses_yarn2=$(detect_yarn2 "$uses_yarn" "$build_dir")
+
+  if [[ "$uses_yarn2" == "true" ]]; then
+    mcount "failures.yarn2-unsupported"
+    meta_set "failure" "yarn2-unsupported"
+    warn "
+      Thanks for trying Heroku with Yarn 2!
+
+      We are busy working to support Yarn 2, but it's not quite there yet.
+      Thanks for your patience while we work to give full support to
+      all of our Yarn users.
+
+      To use Yarn 1, set the local environment to use Yarn 1 and regenerate the
+      yarn.lock file for this app. When checking in the regenerated lockfile,
+      remember to remove files that have been generated by Yarn 2, which may
+      include yarnrc.yml, .yarn directory, pnp.js.
+      "
+    fail
+  fi
+}
+
 fail_multiple_lockfiles() {
   local has_modern_lockfile=false
   if [ -f "${1:-}/yarn.lock" ] || [ -f "${1:-}/package-lock.json" ]; then

lib/yarn2.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+YQ="$BP_DIR/etc/vendor/yq-$(get_os)"
+
+detect_yarn2() {
+  local uses_yarn="$1"
+  local build_dir="$2"
+  local yml_metadata
+  local version
+
+  yml_metadata=$($YQ r "$build_dir/yarn.lock" __metadata 2>&1)
+
+  # grep for version in case the output is a parsing error
+  version=$(echo "$yml_metadata" | grep version)
+
+  if [[ "$uses_yarn" == "true" && "$version" != "" ]]; then
+    echo "true"
+  else
+    echo "false"
+  fi
+}

test/fixtures/yarn-2-without-cache/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "yarn-2-without-cache",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "engines": {
+    "yarn": "1.x"
+  },
+  "dependencies": {
+    "lodash": "^4.16.4"
+  },
+  "devDependencies": {
+    "debug": "^4.1.1"
+  }
+}

test/fixtures/yarn-2-without-cache/yarn.lock

@@ -0,0 +1,37 @@
+# This file is generated by running "yarn install" inside your project.
+# Manual changes might be lost - proceed with caution!
+
+__metadata:
+  version: 4
+
+"debug@npm:^4.1.1":
+  version: 4.1.1
+  resolution: "debug@npm:4.1.1"
+  dependencies:
+    ms: ^2.1.1
+  checksum: e3bfa1544ced80ac5764aa313530150af442e5ce53f91090f00e3aff33a8b535ce60a7502d1451b3cbc2b9cd6994b3a08a38fbd3ff7a2ec801ad79d8b457b8e8
+  languageName: node
+  linkType: hard
+
+"lodash@npm:^4.16.4":
+  version: 4.17.15
+  resolution: "lodash@npm:4.17.15"
+  checksum: b018ec8d4c95f14a4b57005a247eca1bc25639322939471a1958d3bc721b4f18e90edb6ea564854593a8bc1f94956a0352cf0cd372991b98c42d61c0cd11e5a3
+  languageName: node
+  linkType: hard
+
+"ms@npm:^2.1.1":
+  version: 2.1.2
+  resolution: "ms@npm:2.1.2"
+  checksum: 2a3d955e5199024d4b18630ff47c21b52703a5e892615ae233486b8108f26b5493736009754263eebae765ab79d6e20327dad6e52d7843b689d404245e286549
+  languageName: node
+  linkType: hard
+
+"yarn-2-without-cache@workspace:.":
+  version: 0.0.0-use.local
+  resolution: "yarn-2-without-cache@workspace:."
+  dependencies:
+    debug: ^4.1.1
+    lodash: ^4.16.4
+  languageName: unknown
+  linkType: soft