Skip the images build when no images changed

Implements #743

.travis.yml

@@ -12,6 +12,9 @@ addons:
     packages:
       - docker-ce
 
+before_install:
+  - source functions.sh && images_updated $TRAVIS_COMMIT_RANGE || tests_updated $TRAVIS_COMMIT_RANGE || travis_terminate
+
 script: ./test-build.sh $NODE_VERSION $VARIANT
 
 stages:

functions.sh

@@ -239,3 +239,54 @@ function sort_versions() {
 
   echo "${sorted[@]}"
 }
+
+function commit_range() {
+  local commit_id_end=${1}
+  shift
+  local commit_id_start=${1}
+
+  if [ -z "${commit_id_start}" ]; then
+    if [ -z "${commit_id_end}" ]; then
+      echo "HEAD~1..HEAD"
+    elif [[ "${commit_id_end}" =~ .. ]]; then
+      echo "${commit_id_end}"
+    else
+      echo "${commit_id_end}~1..${commit_id_end}"
+    fi
+  else
+    echo "${commit_id_end}..${commit_id_start}"
+  fi
+}
+
+function images_updated() {
+  local commit_range
+  local versions
+  local images_changed
+
+  commit_range="$(commit_range "$@")"
+
+  IFS=' ' read -ra versions <<<"$(
+    IFS=','
+    get_versions
+  )"
+  images_changed=$(git diff --name-only "${commit_range}" "${versions[@]}")
+
+  if [ -z "${images_changed}" ]; then
+    return 1
+  fi
+  return 0
+}
+
+function tests_updated() {
+  local commit_range
+  local test_changed
+
+  commit_range="$(commit_range "$@")"
+
+  test_changed=$(git diff --name-only "${commit_range}" test*)
+
+  if [ -z "${test_changed}" ]; then
+    return 1
+  fi
+  return 0
+}

generate-stackbrew-pr.sh

@@ -31,22 +31,6 @@ UPSTREAM_SLUG="docker-library/${REPO_NAME}"
 DOCKER_SLUG="nodejs/docker-node"
 gitpath="../${REPO_NAME}"
 
-function updated() {
-  local versions
-  local images_changed
-
-  IFS=' ' read -ra versions <<<"$(
-    IFS=','
-    get_versions
-  )"
-  images_changed=$(git diff --name-only "${COMMIT_ID}".."${COMMIT_ID}"~1 "${versions[@]}")
-
-  if [ -z "${images_changed}" ]; then
-    return 1
-  fi
-  return 0
-}
-
 function auth_header() {
   echo "Authorization: token ${GITHUB_API_TOKEN}"
 }
@@ -104,7 +88,7 @@ function comment_payload() {
   }"
 }
 
-if updated; then
+if images_updated "${COMMIT_ID}"; then
 
   permission_check
 

travis.yml.template

@@ -10,6 +10,9 @@ addons:
     packages:
       - docker-ce
 
+before_install:
+  - source functions.sh && images_updated $TRAVIS_COMMIT_RANGE || tests_updated $TRAVIS_COMMIT_RANGE || travis_terminate
+
 script: ./test-build.sh $NODE_VERSION $VARIANT
 
 stages: