Add some comments

.woodpecker.yml

@@ -1,19 +1,24 @@
-variables:
-  - &flutter_version '3.13.6'
-
 steps:
   docker-build:
     image: woodpeckerci/plugin-docker-buildx
     settings:
+      # Push to my registry
       repo: git.polynom.me/papatutuwawa/docker-flutter
       registry: git.polynom.me
-      platforms: linux/arm64/v8
-      tag: *flutter_version
-      build_args:
-        - FLUTTER_VERSION=3.13.6
-      auto_tag: true
       username:
         from_secret: repository_username
       password:
         from_secret: repository_password
+      # Build only for ARM64
+      platforms: linux/arm64/v8
+      # Build the correct version
+      build_args:
+        - FLUTTER_VERSION=3.13.6
+      # Tag :<version> and :latest
+      tag: 3.13.6
+      auto_tag: true
+      # Save storage
+      purge: true
     secrets: [ repository_username, repository_password ]
+    when:
+      event: [push]

Dockerfile

@@ -3,18 +3,17 @@ FROM debian:bookworm-20230919-slim
 # The version of Flutter to use
 ARG FLUTTER_VERSION
 
-RUN echo $FLUTTER_VERSION
-
-# Set environment variables
+# Add Flutter to the PATH
 ENV PATH="$PATH:/opt/flutter/bin"
 
+# It turns out that the provided tarballs all expect x86 and thus bundle
+# the x86 build of Dart, which obviously does not work. Thus, we have to
+# fetch the repo from Github and use that instead. Then Flutter fetches the
+# correct Dart build and everything should work.
 RUN apt-get update && apt-get install -y git curl unzip
 RUN mkdir -p /opt && \
     git clone --depth=1 -b $FLUTTER_VERSION https://github.com/flutter/flutter.git /opt/flutter
 
-# Install Flutter's Linux dependencies and pre-cache dependencies
-#RUN apt-get install clang cmake ninja-build pkg-config libgtk3-dev liblzma-dev libstdc++-12-dev && \
-#    flutter precache && \
-#    rm -rf /var/lib/apt/lists/*
+# Pre-cache dependencies
 RUN flutter precache && \
     rm -rf /var/lib/apt/lists/*