From 180763a87d1ef1c44c73f6555ed172b969761c25 Mon Sep 17 00:00:00 2001
From: Bert Goethals <bert@bertg.be>
Date: Thu, 28 Jan 2021 20:10:31 +0100
Subject: [PATCH] Provide bare action implementation

---
 action.yml    | 23 +++++++++++++++++++++++
 entrypoint.sh | 22 ++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 action.yml
 create mode 100755 entrypoint.sh

diff --git a/action.yml b/action.yml
new file mode 100644
index 0000000..c3c7692
--- /dev/null
+++ b/action.yml
@@ -0,0 +1,23 @@
+name: Detect path Changes
+inputs:
+  base_branch:
+    description: "Branch to compare with"
+    required: false
+    default: ${{ github.event.repository.default_branch  }}
+  pathspec:
+    description: "Pattern used to limit paths in the `git diff-tree` command."
+    required: false
+    default: ""
+outputs:
+  changed:
+    description: "Whether or not files matched by the pathspec were changed."
+    value: ${{ steps.run.outputs.changed }}
+  fork_point_sha:
+    description: "The sha we compared with"
+    value: ${{ steps.run.outputs.fork_point_sha }}
+runs:
+  using: 'composite'
+  steps:
+    - id: run
+      run: ${{ github.action_path }}/entrypoint.sh ${{ inputs.base_branch }} ${{ inputs.pathspec }}
+      shell: bash
diff --git a/entrypoint.sh b/entrypoint.sh
new file mode 100755
index 0000000..b69dc63
--- /dev/null
+++ b/entrypoint.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+set -e
+
+BASE_BRANCH="remotes/origin/$1"
+PATHSPEC=$2
+FORK_POINT_SHA=$(git merge-base --fork-point $BASE_BRANCH)
+
+echo ::set-output name=fork_point_sha::$FORK_POINT_SHA
+
+function check() {
+
+  if [[ -z "$(git diff --name-only $FORK_POINT_SHA $PATHSPEC)" ]];
+  then
+    echo "Detected no changes on $PATHSPEC since $FORK_POINT_SHA"
+    echo ::set-output name=changed::false
+  else
+    echo "Detected changes on $PATHSPEC since $FORK_POINT_SHA"
+    echo ::set-output name=changed::true
+  fi
+}
+
+check