feat: Test building with swift:slim, as a matrix strategy in ci.

.gitea/workflows/ci.yaml

@@ -15,6 +15,9 @@ env:
 # There is a single job in this workflow. It's configured to run on the latest available version of Ubuntu.
 jobs:
   build-and-push-image:
+    strategy:
+      matrix:
+        version: ["latest", "slim"]
     runs-on: ubuntu-latest
     # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.
     permissions:
@@ -48,6 +51,7 @@ jobs:
           tags: |
             type=ref,event=branch
             type=sha
+            type=raw,${{ matrix.version }}
       - name: Build and push Docker image
         id: push
         uses: docker/build-push-action@v6
@@ -55,5 +59,7 @@ jobs:
           context: .
           file: Dockerfile
           push: true
+          build-args: |
+            SWIFT_VERSION="swift:${{ matrix.version }}"
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}

.gitea/workflows/release.yaml

@@ -50,7 +50,7 @@ jobs:
             type=ref,event=branch
             type=semver,pattern={{version}}
             type=sha
-            type=raw,value=latest
+            type=raw,value=${{ matrix.version }}
       - name: Build and push Docker image
         id: push
         uses: docker/build-push-action@v6

Dockerfile

@@ -1,4 +1,6 @@
-FROM docker.io/swift:latest AS build
+ARG SWIFT_VERSION="swift:latest"
+
+FROM docker.io/${SWIFT_VERSION} AS build
 
 RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true \
     && apt-get -q update \
@@ -13,7 +15,7 @@ RUN rustup default stable && \
 	/root/.cargo/bin/bob install nightly && \
 	/root/.cargo/bin/bob use nightly
 
-FROM docker.io/swift:latest
+FROM docker.io/${SWIFT_VERSION}
 
 RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true \
     && apt-get -q update \