feat: switch to Alpine base image and update package installation

.dockerignore

@@ -6,4 +6,4 @@
 !LICENSE
 !README.md
 !entrypoint.sh
-!pip
+!alpine-packages.txt

Dockerfile

@@ -1,33 +1,20 @@
-FROM ubuntu:questing-20251217
-
-# Disable interactive mode
-ENV DEBIAN_FRONTEND=noninteractive
+FROM alpine:3.23.4
 
 # Copy all needed files
 COPY entrypoint.sh /
+COPY alpine-packages.txt /tmp/alpine-packages.txt
 
 # Install needed packages
-SHELL ["/bin/bash", "-euxo", "pipefail", "-c"]
-# hadolint ignore=DL3008
-RUN chmod +x /entrypoint.sh ;\
-  apt-get update -y ;\
-  apt-get install --no-install-recommends -y \
-    gpg-agent \
-    software-properties-common ;\
-  echo 'debconf debconf/frontend select Noninteractive' | debconf-set-selections ;\
-  add-apt-repository ppa:git-core/ppa ;\
-  apt-get update -y ;\
-  apt-get install --no-install-recommends -y \
-    git ;\
-  # Install git-lfs without post-install configuration to avoid dpkg errors \
-  apt-get download git-lfs ;\
-  dpkg --unpack git-lfs*.deb ;\
-  rm -f /var/lib/dpkg/info/git-lfs.postinst ;\
-  dpkg --configure git-lfs ;\
-  apt-get install -f --no-install-recommends -y ;\
-  rm git-lfs*.deb ;\
-  apt-get clean ;\
-  rm -rf /var/lib/apt/lists/*
+SHELL ["/bin/sh", "-euxo", "pipefail", "-c"]
+# hadolint ignore=DL3018
+RUN set -eux; \
+  xargs -r apk add --no-cache < /tmp/alpine-packages.txt; \
+  chmod +x /entrypoint.sh; \
+  git --version; \
+  git-lfs version; \
+  rm -rf /var/cache/*; \
+  rm -rf /root/.cache/*; \
+  rm -rf /tmp/*
 
 # Finish up
 WORKDIR /github/workspace

Taskfile.cicd.yml

@@ -44,9 +44,9 @@ tasks:
       - task: scripts:lint:yamllint
 
   dependency:update:
-    desc: 'No-op: no dedicated dependency updater configured for this profile'
+    desc: Update repository dependencies not covered by Dependabot
     cmds:
-      - task: scripts:dependency:update
+      - task: scripts:packages:update
 
   version:set:
     desc: Update version in README.md and action.yml

Taskfile.scripts.yml

@@ -75,12 +75,9 @@ tasks:
         fi
 
   dependency:update:
-    desc: 'No-op: no dedicated dependency updater configured for this profile'
+    desc: Update dependency metadata for this repository
     cmds:
-      - |
-        echo "INFO: No dedicated dependency updater configured for this repository profile."
-        echo "INFO: Dependabot handles GitHub Actions and package metadata updates."
-        echo "INFO: Keep this task as a safe no-op until a repo-specific dependency updater is defined."
+      - task: packages:update
 
   version:get:
     desc: Get current version
@@ -255,7 +252,22 @@ tasks:
           exit 0
         fi
 
-        base_image="$(sed -nE 's/^FROM[[:space:]]+([^[:space:]]+).*/\1/p' Dockerfile | head -1)"
+        base_image="$(awk '
+          toupper($1) == "FROM" {
+            i = 2
+            while (i <= NF && $i ~ /^--/) {
+              i++
+            }
+            if (i <= NF) {
+              image = $i
+            }
+          }
+          END {
+            if (image != "") {
+              print image
+            }
+          }
+        ' Dockerfile)"
         if [ -z "$base_image" ]; then
           echo "INFO: Could not resolve base image; nothing to update"
           exit 0

alpine-packages.txt

@@ -0,0 +1,3 @@
+bash~=5.3
+git~=2.52
+git-lfs~=3.7

entrypoint.sh

@@ -38,8 +38,60 @@ if [[ "${REPOSITORY_PATH}" == /* ]]; then
   exit 1
 fi
 
-WORKSPACE_DIR="$(realpath -m "${GITHUB_WORKSPACE}")"
-REPO_DIR="$(realpath -m "${GITHUB_WORKSPACE}/${REPOSITORY_PATH}")"
+if [[ -z "${GITHUB_WORKSPACE}" || ! -d "${GITHUB_WORKSPACE}" ]]; then
+  echo "[ERROR] GITHUB_WORKSPACE must point to an existing directory."
+  exit 1
+fi
+
+normalize_relative_path() {
+  local path part normalized
+  local -a parts stack
+
+  path="${1:-.}"
+  IFS='/' read -r -a parts <<< "${path}"
+  stack=()
+
+  for part in "${parts[@]}"; do
+    case "${part}" in
+      ""|".")
+        ;;
+      "..")
+        if (( ${#stack[@]} > 0 )) && [[ "${stack[-1]}" != ".." ]]; then
+          unset 'stack[-1]'
+        else
+          stack+=("..")
+        fi
+        ;;
+      *)
+        stack+=("${part}")
+        ;;
+    esac
+  done
+
+  if (( ${#stack[@]} == 0 )); then
+    printf '.'
+    return
+  fi
+
+  normalized="${stack[0]}"
+  for part in "${stack[@]:1}"; do
+    normalized+="/${part}"
+  done
+  printf '%s' "${normalized}"
+}
+
+WORKSPACE_DIR="$(cd "${GITHUB_WORKSPACE}" && pwd -P)"
+NORMALIZED_REPOSITORY_PATH="$(normalize_relative_path "${REPOSITORY_PATH}")"
+if [[ "${NORMALIZED_REPOSITORY_PATH}" == ".." || "${NORMALIZED_REPOSITORY_PATH}" == ../* ]]; then
+  echo "[ERROR] Input 'repository_path' resolves outside GITHUB_WORKSPACE."
+  exit 1
+fi
+
+if [[ "${NORMALIZED_REPOSITORY_PATH}" == "." ]]; then
+  REPO_DIR="${WORKSPACE_DIR}"
+else
+  REPO_DIR="${WORKSPACE_DIR}/${NORMALIZED_REPOSITORY_PATH}"
+fi
 if [[ "${REPO_DIR}" != "${WORKSPACE_DIR}" && "${REPO_DIR}" != "${WORKSPACE_DIR}"/* ]]; then
   echo "[ERROR] Input 'repository_path' resolves outside GITHUB_WORKSPACE."
   exit 1

tests/docker/local-image.yml

@@ -4,25 +4,22 @@ commandTests:
   - name: OS version check
     command: cat
     args: [/etc/os-release]
-    expectedOutput: [VERSION_ID="25\.10"]
+    expectedOutput: [VERSION_ID=3\.23]
 
   - name: Required tools installed
     command: bash
     args:
       - -lc
       - command -v bash >/dev/null 2>&1 && command -v git >/dev/null 2>&1 && command -v git-lfs >/dev/null 2>&1
 
-  - name: Apt cache cleaned
+  - name: Temporary and APK cache cleaned
     command: bash
     args:
       - -lc
-      - test ! -d /var/lib/apt/lists || test -z "$(find /var/lib/apt/lists -mindepth 1 -maxdepth 1 2>/dev/null)"
-
-  - name: Temporary apt artifacts removed
-    command: bash
-    args:
-      - -lc
-      - test ! -e /git-lfs*.deb
+      - >-
+        test ! -f /tmp/alpine-packages.txt &&
+        (test ! -d /var/cache/apk || test -z "$(find /var/cache/apk -mindepth 1 -maxdepth 1 2>/dev/null)") &&
+        (test ! -d /root/.cache || test -z "$(find /root/.cache -mindepth 1 -maxdepth 1 2>/dev/null)")
 
   - name: Entrypoint handles default repository path
     command: bash