Implements smart merge v2 (#4177)

Author: arcanis

.github/workflows/pr-smart-merge.yml

@@ -1,41 +1,47 @@
 on:
-  workflow_dispatch:
-    inputs:
-      pr:
-        description: 'The pull request to update'
-        required: true
+  pull_request_target:
+    types: [labeled]
 
-name: 'Smart master merge'
+name: 'Smart merge'
 jobs:
-  merge:
-    name: 'Merge master into the PR'
+  reset:
+    name: 'Remove the label'
     runs-on: ubuntu-latest
+    if: |
+      github.event.label.name == 'infra: pending update'
 
     steps:
-    - uses: actions/checkout@master
+      - name: 'Remove the label'
+        uses: actions/github-script@v6
+        with:
+          script: |
+            await github.rest.issues.removeLabel({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               issue_number: context.issue.number,
+               name: context.payload.label.name,
+            });
+
+  generate:
+    name: 'Generate an update changeset'
+    runs-on: ubuntu-latest
+    needs: reset
+    permissions:
+      contents: read
+
+    steps:
+    - uses: actions/checkout@v3
       with:
-        ref: master
-        token: ${{secrets.YARNBOT_TOKEN}}
+        ref: ${{github.event.pull_request.head.sha}}
         fetch-depth: 0
 
     - uses: ./.github/actions/prepare
 
-    - name: 'Update, commit, and upload the artifacts'
+    - name: 'Generate the changeset'
       run: |
-        PR_META=$(curl https://api.github.com/repos/yarnpkg/berry/pulls/'${{github.event.inputs.pr}}')
+        git fetch origin master
 
-        PR_REPO=$(jq -r .head.repo.full_name <<< "$PR_META")
-        PR_REF=$(jq -r .head.ref <<< "$PR_META")
-
-        git config user.name "Yarn Bot"
-        git config user.email [email protected]
-
-        git remote add pr-source https://'${{secrets.YARNBOT_TOKEN}}'@github.com/"$PR_REPO".git
-
-        git fetch pr-source "$PR_REF":local
-        git checkout local
-
-        if ! git merge origin/master; then
+        if ! git merge --no-commit origin/master; then
           export YARN_ENABLE_IMMUTABLE_INSTALLS=0
 
           if git diff --name-only --diff-filter=U | grep .pnp.cjs; then
@@ -63,9 +69,58 @@ jobs:
             git checkout --theirs packages/yarnpkg-parsers/sources/grammars/shell.js
             yarn grammar:shell
           fi
-
-          git add .pnp.cjs packages/yarnpkg-pnp/sources/hook.js packages/yarnpkg-pnp/sources/esm-loader/built-loader.js packages/yarnpkg-parsers/sources/grammars/shell.js
-          git commit -m 'Auto-merge with master'
         fi
 
-        git push pr-source local:"$PR_REF"
+        yarn test:lint --fix
+
+    - name: Generate the artifacts
+      run: |
+        git config user.name "Yarn Bot"
+        git config user.email [email protected]
+
+        git diff > merge-conflict-resolution.patch
+
+    - name: Store the merge conflict resolution
+      uses: actions/upload-artifact@v3
+      with:
+        name: merge-conflict-resolution
+        path: merge-conflict-resolution.patch
+
+  apply:
+    name: 'Apply the update changeset'
+    runs-on: ubuntu-latest
+    needs: generate
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: ${{github.event.pull_request.head.sha}}
+          fetch-depth: 0
+
+      - name: Retrieve the merge conflict resolution
+        uses: actions/download-artifact@v3
+        with:
+          name: merge-conflict-resolution
+
+      - name: Apply the changeset
+        env:
+          GH_BOT_TOKEN: ${{secrets.YARNBOT_TOKEN}}
+          GH_REPO_NAME: ${{github.event.pull_request.head.repo.full_name}}
+          GH_HEAD_REF: ${{github.event.pull_request.head.ref}}
+        run: |
+          git config user.name "Yarn Bot"
+          git config user.email [email protected]
+
+          git remote add pr-source https://"${GH_BOT_TOKEN}"@github.com/"${GH_REPO_NAME}".git
+
+          git fetch pr-source "$GH_HEAD_REF":local
+          git checkout local
+
+          git fetch origin master
+          git merge --no-commit origin/master || true
+          git add -A
+
+          git apply --allow-empty merge-conflict-resolution.patch
+          git commit --allow-empty -m 'Auto-merge with master'
+
+          git push pr-source local:"$GH_HEAD_REF"

.gitignore

@@ -15,6 +15,9 @@ yarn-error.log
 
 junit.xml
 
+# This file is generated by the Smart Merge workflow
+/merge-conflict-resolution.patch
+
 # The tarballs generated by "yarn pack" are never kept either
 package.tgz
 

packages/yarnpkg-parsers/sources/grammars/shell.js

@@ -176,6 +176,7 @@ GlobText
 
 EnvVariable
   = [a-zA-Z0-9_]+ { return text() }
+  / [A-Za-z0-9_]+ { return text() }
 
 Identifier
   = [$@*?#a-zA-Z0-9_-]+ { return text() }

packages/yarnpkg-parsers/sources/grammars/shell.pegjs

@@ -19,6 +19,9 @@ declare var $$SETUP_STATE: (hrs: typeof hydrateRuntimeState, basePath?: NativePa
 const localFs: typeof fs = {...fs};
 const nodeFs = new NodeFS(localFs);
 
+// This is just a test, I'll remove it asap
+(nodeFs as any).__test = true;
+
 const defaultRuntimeState = $$SETUP_STATE(hydrateRuntimeState);
 const defaultPnpapiResolution = __filename;
 

packages/yarnpkg-pnp/sources/hook.js

@@ -0,0 +1 @@
+test