ci/github-script/prepare: classify branches

.github/workflows/pr.yml

@@ -23,8 +23,8 @@ jobs:
   prepare:
     runs-on: ubuntu-24.04-arm
     outputs:
-      baseBranch: ${{ steps.branches.outputs.base }}
-      headBranch: ${{ steps.branches.outputs.head }}
+      baseBranch: ${{ steps.prepare.outputs.base }}
+      headBranch: ${{ steps.prepare.outputs.head }}
       mergedSha: ${{ steps.prepare.outputs.mergedSha }}
       targetSha: ${{ steps.prepare.outputs.targetSha }}
       systems: ${{ steps.prepare.outputs.systems }}
@@ -44,26 +44,6 @@ jobs:
               core,
             })
 
-      - name: Determine branch type
-        id: branches
-        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
-        with:
-          script: |
-            const { classify } = require('./ci/supportedBranches.js')
-            const { base, head } = context.payload.pull_request
-
-            const baseClassification = classify(base.ref)
-            core.setOutput('base', baseClassification)
-            core.info('base classification:', baseClassification)
-
-            const headClassification =
-              (base.repo.full_name == head.repo.full_name) ?
-              classify(head.ref) :
-              // PRs from forks are always considered WIP.
-              { type: ['wip'] }
-            core.setOutput('head', headClassification)
-            core.info('head classification:', headClassification)
-
       - name: Determine changed files
         id: files
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1

ci/github-script/prepare.js

@@ -1,3 +1,5 @@
+const { classify } = require('../supportedBranches.js')
+
 module.exports = async ({ github, context, core }) => {
   const pull_number = context.payload.pull_request.number
 
@@ -20,6 +22,8 @@ module.exports = async ({ github, context, core }) => {
       continue
     }
 
+    const { base, head } = prInfo
+
     let mergedSha, targetSha
 
     if (prInfo.mergeable) {
@@ -39,7 +43,7 @@ module.exports = async ({ github, context, core }) => {
       targetSha = (
         await github.rest.repos.compareCommitsWithBasehead({
           ...context.repo,
-          basehead: `${prInfo.base.sha}...${prInfo.head.sha}`,
+          basehead: `${base.sha}...${head.sha}`,
         })
       ).data.merge_base_commit.sha
     }
@@ -52,6 +56,18 @@ module.exports = async ({ github, context, core }) => {
 
     core.setOutput('systems', require('../supportedSystems.json'))
 
+    const baseClassification = classify(base.ref)
+    core.setOutput('base', baseClassification)
+    core.info('base classification:', baseClassification)
+
+    const headClassification =
+      base.repo.full_name === head.repo.full_name
+        ? classify(head.ref)
+        : // PRs from forks are always considered WIP.
+          { type: ['wip'] }
+    core.setOutput('head', headClassification)
+    core.info('head classification:', headClassification)
+
     return
   }
   throw new Error(