diff --git a/get-changed-paths.sh b/get-changed-paths.sh
index 92260706..d2ca0f1d 100755
--- a/get-changed-paths.sh
+++ b/get-changed-paths.sh
@@ -8,6 +8,11 @@ INPUT_SEPARATOR="${INPUT_SEPARATOR//$'\n'/'%0A'}"
 INPUT_SEPARATOR="${INPUT_SEPARATOR//$'\r'/'%0D'}"
 
 GITHUB_OUTPUT=${GITHUB_OUTPUT:-""}
+DIFF="..."
+
+if [[ -z $GITHUB_BASE_REF ]]; then
+  DIFF=".."
+fi
 
 if [[ $INPUT_QUOTEPATH == "false" ]]; then
   git config --global core.quotepath off
@@ -24,8 +29,8 @@ function get_diff() {
   sha="$2"
   filter="$3"
   while IFS='' read -r sub; do
-    sub_commit_pre="$(git diff "$base"..."$sha" -- "$sub" | grep '^[-]Subproject commit' | awk '{print $3}')"
-    sub_commit_cur="$(git diff "$base"..."$sha" -- "$sub" | grep '^[+]Subproject commit' | awk '{print $3}')"
+    sub_commit_pre="$(git diff "$base$DIFF$sha" -- "$sub" | grep '^[-]Subproject commit' | awk '{print $3}')"
+    sub_commit_cur="$(git diff "$base$DIFF$sha" -- "$sub" | grep '^[+]Subproject commit' | awk '{print $3}')"
     if [ -n "$sub_commit_cur" ]; then
     (
       cd "$sub" && (
@@ -37,9 +42,9 @@ function get_diff() {
   done < <(git submodule | awk '{print $2}')
 
   if [[ "$INPUT_DIR_NAMES" == "true" ]]; then
-    git diff --diff-filter="$filter" --name-only --ignore-submodules=all "$base"..."$sha" | xargs -I {} dirname {} | uniq
+    git diff --diff-filter="$filter" --name-only --ignore-submodules=all "$base$DIFF$sha" | xargs -I {} dirname {} | uniq
   else
-    git diff --diff-filter="$filter" --name-only --ignore-submodules=all "$base"..."$sha"
+    git diff --diff-filter="$filter" --name-only --ignore-submodules=all "$base$DIFF$sha"
   fi
 }
 
@@ -47,8 +52,8 @@ function get_renames() {
   base="$1"
   sha="$2"
   while IFS='' read -r sub; do
-    sub_commit_pre="$(git diff "$base"..."$sha" -- "$sub" | grep '^[-]Subproject commit' | awk '{print $3}')"
-    sub_commit_cur="$(git diff "$base"..."$sha" -- "$sub" | grep '^[+]Subproject commit' | awk '{print $3}')"
+    sub_commit_pre="$(git diff "$base$DIFF$sha" -- "$sub" | grep '^[-]Subproject commit' | awk '{print $3}')"
+    sub_commit_cur="$(git diff "$base$DIFF$sha" -- "$sub" | grep '^[+]Subproject commit' | awk '{print $3}')"
     if [ -n "$sub_commit_cur" ]; then
     (
       cd "$sub" && (
@@ -60,9 +65,9 @@ function get_renames() {
   done < <(git submodule | awk '{print $2}')
 
   if [[ "$INPUT_DIR_NAMES" == "true" ]]; then
-    git log --name-status --ignore-submodules=all "$base"..."$sha" | grep -E "^R" | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}' | xargs -I {} dirname {} | uniq
+    git log --name-status --ignore-submodules=all "$base$DIFF$sha" | grep -E "^R" | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}' | xargs -I {} dirname {} | uniq
   else
-    git log --name-status --ignore-submodules=all "$base"..."$sha" | grep -E "^R" | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}'
+    git log --name-status --ignore-submodules=all "$base$DIFF$sha" | grep -E "^R" | awk -F '\t' -v d="$INPUT_OLD_NEW_SEPARATOR" '{print $2d$3}'
   fi
 }