Bugfix/lfs

Dockerfile

@@ -2,7 +2,9 @@ FROM alpine:3.11
 
 RUN apk add --no-cache bash
 RUN apk --no-cache add git
+RUN apk --no-cache add git-lfs
 RUN apk --no-cache add jq
 
+
 COPY entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]

README.md

@@ -10,6 +10,9 @@ The path to the submodule, this is required. Do not include leading or trailing
 ### `branch` (optional)
 The name of a branch that the submodule hash must be on (after the push or on the head PR branch)
 
+### `first_parent` (optional)
+Require the submodule's checked-out commit to be an ancestor of the specified branch strictly along the path following first parents only.  That is, the submodule's current HEAD must either currently be or have at some point in the past been the tip of the branch specified.
+
 ### `pass_if_unchanged` (optional)
 For pull request only, if this is included the check will automatically pass if none of the commits modify the submodule. 
 
@@ -52,6 +55,7 @@ jobs:
       with:
         path: "path/to/submodule"
         branch: "main"
+        first_parent: true
         fetch_depth: "50"
         pass_if_unchanged: true
         require_head: true

action.yml

@@ -12,6 +12,10 @@ inputs:
     description: "Which branch the submodule must be on"
     required: false
     default: ''
+  first_parent:
+    description: "Require submodule commit to be an ancestor of specified branch strictly along first-parent path"
+    required: false
+    default: ''
   pass_if_unchanged:
     description: "If the check should always pass if the submodule hasn't been changed on a branch/commit"
     required: false
@@ -32,6 +36,7 @@ inputs:
     description: "Override the path to the github event json file. Used for testing."
     required: false
     default: ''
+
 outputs:
   fails:
     description: "Cause of failure, if run failed"

entrypoint.sh

@@ -176,6 +176,14 @@ if [[ ! -z "${INPUT_BRANCH}" ]]; then
 	echo "${BRANCHES}" | grep "/${INPUT_BRANCH}$" || fail "Submodule ${INPUT_PATH} Hash ${SUBMODULE_HASH} is not on branch ${INPUT_BRANCH}"
 	echo "Submodule is on branch ${INPUT_BRANCH}"
 	echo "::endgroup::"
+
+	if [[ ! -z "${INPUT_FIRST_PARENT}" ]]; then
+		echo "::group::Check First-Parent Ancestry"
+		git rev-list --first-parent ${INPUT_BRANCH} --not ${SUBMODULE_HASH}^@ | grep "${SUBMODULE_HASH}" || fail "Commit ${SUBMODULE_HASH} is not a first-parent ancestor of the tip of ${INPUT_BRANCH}"
+		echo "Commit ${SUBMODULE_HASH} is a first-parent ancestor of the tip of ${INPUT_BRANCH}"
+		echo "::endgroup::"
+	fi
+
 fi