Add pre-commit hook to check licenses

This adds a manual pre-commit hook to check the project for REUSE-compliance. The Check licenses CI job is updated to use the hook.

.gitlab-ci.yml

@@ -25,48 +25,53 @@ workflow:
   variables:
     CI_GITIGNORE_DIR: ${CI_PROJECT_DIR}/.ci_dir
 
-Check licenses:
-  before_script:
-    - python -m pip install --upgrade pip
-    - python -m pip install reuse
-    - reuse --version
-  script:
-    - reuse lint
-  tags:
-    - sphinx
-  rules:
-    - if: $CI_PIPELINE_SOURCE == "web"
-      when: manual
-    - when: always
-  interruptible: true
-
-Check style:
+.common_pre_commit:
   extends: .ci_dir
   variables:
     APK_CACHE_DIR: ${CI_GITIGNORE_DIR}/apk-cache
     PRE_COMMIT_HOME: ${CI_GITIGNORE_DIR}/pre-commit
+    CACHE_POLICY: pull
   before_script:
     - mkdir -p "${APK_CACHE_DIR}"
     - apk update --cache-dir "${APK_CACHE_DIR}"
     - apk add --cache-dir "${APK_CACHE_DIR}" git pre-commit
-  script:
-    - pre-commit run --show-diff-on-failure --color=always --all-files
   tags:
     - alpine
-  rules:
-    - if: $CI_PIPELINE_SOURCE == "web"
-      when: manual
-    - when: always
-  interruptible: true
   cache:
     - key: ${CI_COMMIT_REF_SLUG}
       paths:
         - ${APK_CACHE_DIR}
+      policy: ${CACHE_POLICY}
     - key:
         files:
           - .pre-commit-config.yaml
       paths:
         - ${PRE_COMMIT_HOME}
+      policy: ${CACHE_POLICY}
+
+Check licenses:
+  extends: .common_pre_commit
+  variables:
+    CACHE_POLICY: pull
+  script:
+    - pre-commit run --hook-stage manual reuse
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "web"
+      when: manual
+    - when: always
+  interruptible: true
+
+Check style:
+  extends: .common_pre_commit
+  variables:
+    CACHE_POLICY: pull-push
+  script:
+    - pre-commit run --show-diff-on-failure --color=always --all-files
+  rules:
+    - if: $CI_PIPELINE_SOURCE == "web"
+      when: manual
+    - when: always
+  interruptible: true
 
 include:
   - project: "anw_dienste/ci-templates"