chore(ci): refactor out set up steps (#10249)

Want to keep working on CI every now and then. Starting by cleaning up
some things so it's easier to reason about. Most jobs run the following
steps:

- enable corepack (this should go away one day when the setup node
action supports it)
- set up node
- enable corepack again (for windows)
- set up yarn cache
- yarn install
- build

Refactoring these out into a composite action so that we can save some
lines in ci.yml which is starting to get quite long. I can also document
some things better this way.

.github/actions/set-up-job/action.yml

@@ -0,0 +1,61 @@
+name: Set up job
+description: >
+  Everything you need to run a job in CI.
+  Checkout this repo (redwoodjs/redwood), set up Node.js, yarn install, and build.
+
+inputs:
+  set-up-yarn-cache:
+    description: >
+      For some actions, setting up the yarn cache takes longer than it would to just yarn install.
+    required: false
+    default: true
+
+  yarn-install-directory:
+    description: >
+      The directory to run `yarn install` in.
+    required: false
+
+  build:
+    description: >
+      Whether or not to run `yarn build` to build all the framework packages.
+    required: false
+    default: true
+
+runs:
+  using: composite
+
+  steps:
+    - name: ⬢ Enable Corepack
+      shell: bash
+      run: corepack enable
+
+    - name: ⬢ Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: 20
+
+    # We have to enable Corepack again for Windows. 🤷
+    # In general, we're waiting on [this issue](https://github.com/actions/setup-node/issues/531)
+    # to be resolved so that `actions/setup-node@v4` has first-class Corepack support.
+    - name: ⬢ Enable Corepack
+      if: runner.os == 'Windows'
+      shell: bash
+      run: corepack enable
+
+    - name: 🐈 Set up yarn cache
+      if: inputs.set-up-yarn-cache == 'true'
+      uses: ./.github/actions/set-up-yarn-cache
+
+    # One of our dependencies is on GitHub instead of NPM and without authentication
+    # we'll get rate limited and this step becomes flaky.
+    - name: 🐈 Yarn install
+      shell: bash
+      working-directory: ${{ inputs.yarn-install-directory }}
+      env:
+        GITHUB_TOKEN: ${{ github.token }}
+      run: yarn install --inline-builds
+
+    - name: 🏗️ Build
+      if: inputs.build == 'true'
+      shell: bash
+      run: yarn build

.github/workflows/check-changelog.yml

@@ -16,16 +16,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-
-      - name: Enable Corepack
-        run: corepack enable
-
-      - uses: actions/setup-node@v4
+      - name: Set up job
+        uses: ./.github/actions/set-up-job
         with:
-          node-version: 20
-
-      - run: yarn install
-        working-directory: ./.github/actions/check_changesets
+          set-up-yarn-cache: false
+          yarn-install-directory: ./.github/actions/check_changesets
+          build: false
 
       - name: Check changesets
         uses: ./.github/actions/check_changesets

.github/workflows/check-create-redwood-app.yml

@@ -16,16 +16,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-
-      - name: Enable Corepack
-        run: corepack enable
-
-      - uses: actions/setup-node@v4
+      - name: Set up job
+        uses: ./.github/actions/set-up-job
         with:
-          node-version: 20
-
-      - run: yarn install
-        working-directory: ./.github/actions/check_create_redwood_app
+          set-up-yarn-cache: false
+          yarn-install-directory: ./.github/actions/check_create_redwood_app
+          build: false
 
       - name: Check create redwood app
         uses: ./.github/actions/check_create_redwood_app

.github/workflows/check-test-project-fixture.yml

@@ -17,27 +17,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Enable Corepack
-        run: corepack enable
-
-      - name: ⬢ Set up Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: 20
-
-      - name: 🐈 Set up yarn cache
-        if: "!contains(github.event.pull_request.labels.*.name, 'fixture-ok')"
-        uses: ./.github/actions/set-up-yarn-cache
-
-      - name: 🐈 Yarn install
-        if: "!contains(github.event.pull_request.labels.*.name, 'fixture-ok')"
-        run: yarn install --inline-builds
-        env:
-          GITHUB_TOKEN: ${{ github.token }}
-
-      - name: 🔨 Build
+      - name: Set up job
         if: "!contains(github.event.pull_request.labels.*.name, 'fixture-ok')"
-        run: yarn build
+        uses: ./.github/actions/set-up-job
 
       - name: Rebuild test-project fixture
         if: "!contains(github.event.pull_request.labels.*.name, 'fixture-ok')"