From f2aeabff78c6735d61b7e70f16f01556cc606d96 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoit@matrix.org>
Date: Fri, 23 Dec 2022 14:22:43 +0100
Subject: [PATCH] Setup git lfs

---
 .gitattributes                     |  1 +
 .github/workflows/validate-lfs.yml | 15 +++++++++++++++
 tools/git/validate_lfs.sh          | 29 +++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 .gitattributes
 create mode 100644 .github/workflows/validate-lfs.yml
 create mode 100755 tools/git/validate_lfs.sh

diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000000..0542767eff
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+**/snapshots/**/*.png filter=lfs diff=lfs merge=lfs -text
diff --git a/.github/workflows/validate-lfs.yml b/.github/workflows/validate-lfs.yml
new file mode 100644
index 0000000000..417b95ce2c
--- /dev/null
+++ b/.github/workflows/validate-lfs.yml
@@ -0,0 +1,15 @@
+name: Validate Git LFS
+
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Validate
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          lfs: 'true'
+
+      - run: |
+          ./tools/git/validate_lfs.sh
diff --git a/tools/git/validate_lfs.sh b/tools/git/validate_lfs.sh
new file mode 100755
index 0000000000..ce121057b6
--- /dev/null
+++ b/tools/git/validate_lfs.sh
@@ -0,0 +1,29 @@
+#! /bin/bash
+
+#
+# Copyright (c) 2022 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Based on https://cashapp.github.io/paparazzi/#git-lfs
+
+# Compare the output of `git ls-files ':(attr:filter=lfs)'` against `git lfs ls-files`
+# If there's no diff we assume the files have been committed using git lfs
+diff <(git ls-files ':(attr:filter=lfs)' | sort) <(git lfs ls-files -n | sort) >/dev/null
+
+ret=$?
+if [[ $ret -ne 0 ]]; then
+  echo >&2 "Detected files committed without using Git LFS."
+  echo >&2 "Install git lfs (eg brew install git-lfs) and run 'git lfs install --local' within the root repository directory and re-commit your files."
+  exit 1
+fi