Refactor Docker build workflow to improve semver check and update tagging logic

Author: MatInGit

.github/workflows/docker-build.yml

@@ -1,8 +1,9 @@
 name: Build & Push Docker Images on Tag
+
 on:
   push:
     tags:
-      - 'v*'  # Triggers only on tags like v0.1.2, v0.1.2.dev1, etc.
+      - 'v*'  # Triggers on tags like v0.1.2, v0.1.2.dev1, etc.
   workflow_dispatch:
 
 jobs:
@@ -21,6 +22,15 @@ jobs:
           echo "VERSION=${TAG_NAME}" >> $GITHUB_ENV
           echo "version=${TAG_NAME}" >> $GITHUB_OUTPUT
 
+      - name: Determine if version is pure semver (e.g. v0.1.2)
+        id: semver_check
+        run: |
+          if echo "${{ steps.vars.outputs.version }}" | grep -Eq '^v[0-9]+\.[0-9]+\.[0-9]+$'; then
+            echo "is_release=true" >> $GITHUB_OUTPUT
+          else
+            echo "is_release=false" >> $GITHUB_OUTPUT
+          fi
+
       - name: Log in to Docker Hub
         uses: docker/login-action@v3
         with:
@@ -47,10 +57,10 @@ jobs:
           docker push $IMAGE_BASE:torch-${VERSION}
           docker push $IMAGE_BASE:tensorflow-${VERSION}
 
-      - name: Tag and push latest if version is pure semver
-        if: ${{ steps.vars.outputs.version =~ '^v[0-9]+\\.[0-9]+\\.[0-9]+$' }}
+      - name: Tag and push latest if release version
+        if: ${{ steps.semver_check.outputs.is_release == 'true' }}
         run: |
-          echo "Tag is a pure semver release — tagging latest"
+          echo "Tag is a release — tagging latest"
 
           docker tag $IMAGE_BASE:base-${VERSION} $IMAGE_BASE:base-latest
           docker tag $IMAGE_BASE:torch-${VERSION} $IMAGE_BASE:torch-latest