From a53d74f700f2982646d538e66ce35cbfc8d4e826 Mon Sep 17 00:00:00 2001
From: Tonye Jack <jtonye@ymail.com>
Date: Sat, 26 Feb 2022 05:09:14 -0500
Subject: [PATCH] fix: handle errors for repositories without any previous
 commit history (#404)

* fix: Handle errors for repositories without any previous commit history

Fixes: #365

* Update diff-sha.sh
---
 diff-sha.sh | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/diff-sha.sh b/diff-sha.sh
index fe2bcd48..153b5414 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -52,7 +52,11 @@ if [[ -z $GITHUB_BASE_REF ]]; then
   CURRENT_BRANCH=$TARGET_BRANCH
 
   if [[ -z $INPUT_BASE_SHA ]]; then
-    PREVIOUS_SHA=$(git rev-list --no-merges -n 1 HEAD^1 2>&1) && exit_status=$? || exit_status=$?
+    if [[ $(git rev-list --count HEAD) -gt 1 ]]; then
+      PREVIOUS_SHA=$(git rev-list --no-merges -n 1 HEAD^1 2>&1) && exit_status=$? || exit_status=$?
+    else
+      PREVIOUS_SHA=$CURRENT_SHA
+    fi
   else
     PREVIOUS_SHA=$INPUT_BASE_SHA && exit_status=$? || exit_status=$?
     TARGET_BRANCH=$(git name-rev --name-only "$PREVIOUS_SHA" 2>&1) && exit_status=$? || exit_status=$?