diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index 1490c6a..a2c680b 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -10,6 +10,8 @@ on:
     branches: [ "main", "devel" ]
     # Publish semver tags as releases.
     tags: [ 'v*.*.*' ]
+  pull_request:
+    branches: [main, devel]
   workflow_dispatch:
 
 env:
diff --git a/Dockerfile b/Dockerfile
index 1407623..1c8d604 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -22,12 +22,14 @@ ENV RENV_CONFIG_SANDBOX_ENABLED=FALSE
 
 COPY ./renv ./renv
 COPY .Rprofile .
+
+# Both renv.lock and DESCRIPTION are needed to restore the R environment
 COPY renv.lock .
+COPY DESCRIPTION .
 
 RUN R -e 'renv::restore()'
 
 COPY .Rbuildignore .
-COPY DESCRIPTION .
 COPY NAMESPACE .
 COPY inst/ ./inst
 COPY R/ ./R