[wip] automate versioned Homebrew formula publishing

.github/workflows/goreleaser.yml

@@ -7,9 +7,63 @@ on:
       - '!latest'
 
 jobs:
+  # goreleaser-pre copies the main formula in our Homebrew tap for the last release
+  # (second latest tag) to a versioned formula, so that it is preserved when goreleaser
+  # runs and overwrites the main formula with the latest build.
+  goreleaser-pre:
+    name: Copy previous release
+    runs-on: ubuntu-latest
+    outputs:
+      second_latest_tag: ${{ env.second_latest_tag }}
+      latest_tag: ${{ env.latest_tag }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Fetch latest and second-latest tags
+        run: |
+          echo "second_latest_tag=$(git tag --sort=taggerdate | tail -2 | sed -n 1p)" >> $GITHUB_ENV
+          echo "latest_tag=$(git tag --sort=taggerdate | tail -1)" >> $GITHUB_ENV
+      - name: Set versioning variables
+        run: |
+          echo "versioned_formula_file=Formula/src-cli@${{ env.second_latest_tag }}.rb" >> $GITHUB_ENV
+          echo "versioned_classname=SrcCliAT$(echo ${{ env.second_latest_tag }} | sed 's/\.//g')" >> $GITHUB_ENV
+      - name: Log variables
+        run: |
+          echo "Second latest tag: ${{ env.second_latest_tag }}"
+          echo "Versioned formula file: ${{ env.versioned_formula_file }}"
+          echo "Versioned classname: ${{ env.versioned_classname }}"
+      - name: Checkout Homebrew tap
+        uses: actions/checkout@v3
+        with:
+          repository: sourcegraph/homebrew-src-cli
+          fetch-depth: 0
+          token: ${{ secrets.BOT_CROSS_REPO_PAT }}
+      - name: Copy main release formula file to versioned formula file
+        run: cp Formula/src-cli.rb ${{ env.versioned_formula_file }}
+      # Homebrew expects the name of the class in a versioned formula file to be of the
+      # format {Formula}AT{Major}{Minor}{Patch}, but the main formula classname is just
+      # {Formula}, so we manually patch the name: SrcCli -> SrcCliAT###
+      - name: Rename formula classname
+        run: sed -i 's/class SrcCli/class ${{ env.versioned_classname }}/' ${{ env.versioned_formula_file }}
+      - name: Commit result
+        run: |
+          git config user.name sourcegraph-bot
+          git config user.email sourcegraph-bot-github@sourcegraph.com
+          git add .
+          git commit -m "Copy previous release"
+          git push
+
   goreleaser:
     name: release
     runs-on: ubuntu-latest
+    needs: goreleaser-pre
+    # Passthrough for the outputs from the first job so that they're also available in
+    # goreleaser-post
+    outputs:
+      second_latest_tag: ${{ needs.goreleaser-pre.outputs.second_latest_tag }}
+      latest_tag: ${{ needs.goreleaser-pre.outputs.latest_tag }}
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -33,6 +87,41 @@ jobs:
         env:
           # Use separate access token, because we need a scope:repo token to publish the brew formula.
           GITHUB_TOKEN: ${{ secrets.GH_PAT }}
+
+  # goreleaser-post updates the symlink name to refer to the new release version. The
+  # symlink enables users to install the latest src-cli with the versioned command:
+  # $ brew install sourcegraph/src-cli/src-cli@X.Y.Z
+  # alongside the command to install it via the main formula:
+  # $ brew install sourcegraph/src-cli/src-cli
+  goreleaser-post:
+    name: Create new release version symlink
+    runs-on: ubuntu-latest
+    needs: goreleaser
+    steps:
+      - name: Set variables
+        run: |
+          echo "old_symlink_name=Aliases/src-cli@${{ needs.goreleaser.outputs.second_latest_tag }}" >> $GITHUB_ENV
+          echo "new_symlink_name=Aliases/src-cli@${{ needs.goreleaser.outputs.latest_tag }}" >> $GITHUB_ENV
+      - name: Log variables
+        run: |
+          echo "Old symlink: ${{ env.old_symlink_name }}"
+          echo "New symlink: ${{ env.new_symlink_name }}"
+      - name: Checkout Homebrew tap
+        uses: actions/checkout@v3
+        with:
+          repository: sourcegraph/homebrew-src-cli
+          fetch-depth: 0
+          token: ${{ secrets.BOT_CROSS_REPO_PAT }}
+      - name: Replace symlink
+        run: mv ${{ env.old_symlink_name }} ${{ env.new_symlink_name }}
+      - name: Commit result
+        run: |
+          git config user.name sourcegraph-bot
+          git config user.email sourcegraph-bot-github@sourcegraph.com
+          git add .
+          git commit -m "Update latest release symlink"
+          git push
+
   npm:
     runs-on: ubuntu-latest
     needs: goreleaser

.github/workflows/lsif.yml

@@ -1,6 +1,7 @@
 name: LSIF
 on:
   - push
+
 jobs:
   lsif-go:
     runs-on: ubuntu-latest

README.markdown

@@ -41,6 +41,14 @@ curl -L https://sourcegraph.example.com/.api/src-cli/src_darwin_amd64 -o /usr/lo
 chmod +x /usr/local/bin/src
 ```
 
+or, if you know the specific version to target, for example 3.43.2:
+
+```bash
+brew install sourcegraph/src-cli/src-cli@3.43.2
+```
+
+> Note: Versioned formulas are available on Homebrew for Sourcegraph versions 3.43.2 and later.
+
 ### Installation: Linux
 
 #### Latest version