add explicit GITHUB_BRANCH_NAME - PR is working on a detached commit

Author: artcz

.github/workflows/preview.yml

@@ -9,6 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       PREVIEW_HOSTNAME: ep-preview.click
+      GITHUB_BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
 
     steps:
       - name: Checkout
@@ -41,7 +42,7 @@ jobs:
 
       - name: Get current branch name
         run: |
-          BRANCH_NAME=$(make safe_branch)
+          BRANCH_NAME=$(make safe_branch BRANCH=$GITHUB_BRANCH_NAME)
           echo "BRANCH_NAME=${BRANCH_NAME}" >> $GITHUB_ENV
 
       - name: ssh keyscan

Makefile

@@ -15,7 +15,7 @@ export GIT_VERSION ?= $(shell git rev-parse --short HEAD)
 # Variables for deploy
 # ====================
 # Auto-detect and sanitize current git branch
-BRANCH := $(shell git rev-parse --abbrev-ref HEAD)
+BRANCH ?= $(shell git rev-parse --abbrev-ref HEAD)
 # Replace "/" and other non-alphanumeric characters with "-"
 SAFE_BRANCH := $(shell echo "$(BRANCH)" | sed 's/[^A-Za-z0-9._-]/-/g')
 FORCE_DEPLOY ?= false