diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a250a675017..2a38624a091 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,6 +8,9 @@ on:
   pull_request:
     branches:
       - main
+  pull_request_review:
+    types:
+      - submitted
 
 jobs:
   shellcheck:
@@ -116,6 +119,29 @@ jobs:
         shell:
           bash
 
+  test-similar-base-and-commit-sha:
+    name: Test changed-files similar base and commit sha
+    runs-on: ${{ matrix.platform }}
+    strategy:
+      fail-fast: false
+      max-parallel: 4
+      matrix:
+        platform: [ubuntu-latest, windows-latest, macos-latest, macos-11, ubuntu-18.04, windows-2022]
+
+    steps:
+      - name: Checkout to branch
+        uses: actions/checkout@v3
+
+      - name: Run changed-files with a single commit history
+        id: changed-files
+        uses: ./
+
+      - name: Show output
+        run: |
+          echo '${{ toJSON(steps.changed-files.outputs) }}'
+        shell:
+          bash
+
   test-non-existent-base-sha:
     name: Test changed-files non existent base sha
     runs-on: ${{ matrix.platform }}
diff --git a/diff-sha.sh b/diff-sha.sh
index 2ded6dd0679..50e57d061c8 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -25,7 +25,7 @@ fi
 echo "::debug::Getting HEAD SHA..."
 
 if [[ -z $INPUT_SHA ]]; then
-  CURRENT_SHA=$(git rev-list --no-merges -n 1 HEAD 2>&1) && exit_status=$? || exit_status=$?
+  CURRENT_SHA=$(git rev-list -n 1 "HEAD" 2>&1) && exit_status=$? || exit_status=$?
 else
   CURRENT_SHA=$INPUT_SHA && exit_status=$? || exit_status=$?
 fi
@@ -37,25 +37,32 @@ if [[ $exit_status -ne 0 ]]; then
   git --version
   echo "::error::You seem to be missing 'fetch-depth: 0' or 'fetch-depth: 2'. See https://github.com/tj-actions/changed-files#usage"
   exit 1
+else
+  echo "::debug::Current SHA: $CURRENT_SHA"
 fi
 
 if [[ -z $GITHUB_BASE_REF ]]; then
   TARGET_BRANCH=${GITHUB_REF/refs\/heads\//}
   CURRENT_BRANCH=$TARGET_BRANCH
 
+  echo "::debug::GITHUB_BASE_REF unset using $TARGET_BRANCH..."
+
   if [[ -z $INPUT_BASE_SHA ]]; then
-    git fetch --no-tags -u --progress --depth=2 origin "${CURRENT_BRANCH}":"${CURRENT_BRANCH}" &&
-    exit_status=$? || exit_status=$?
+    git fetch --no-tags -u --progress --depth=2 origin "${CURRENT_BRANCH}":"${CURRENT_BRANCH}" && exit_status=$? || 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=$? || exit_status=$?
+    if [[ $(git rev-list --count "HEAD") -gt 1 ]]; then
+      PREVIOUS_SHA=$(git rev-list -n 1 "HEAD^1" 2>&1) && exit_status=$? || exit_status=$?
+      echo "::debug::Previous SHA: $PREVIOUS_SHA"
     else
       PREVIOUS_SHA=$CURRENT_SHA && exit_status=$? || exit_status=$?
       echo "::debug::Initial commit detected"
+      echo "::debug::Previous SHA: $PREVIOUS_SHA"
     fi
   else
     PREVIOUS_SHA=$INPUT_BASE_SHA && exit_status=$? || exit_status=$?
     TARGET_BRANCH=$(git name-rev --name-only "$PREVIOUS_SHA" 2>&1) && exit_status=$? || exit_status=$?
+    echo "::debug::Previous SHA: $PREVIOUS_SHA"
+    echo "::debug::Target branch: $TARGET_BRANCH"
   fi
 
   git rev-parse --quiet --verify "$PREVIOUS_SHA^{commit}" 1>/dev/null 2>&1 && exit_status=$? || exit_status=$?
@@ -69,19 +76,25 @@ else
   TARGET_BRANCH=$GITHUB_BASE_REF
   CURRENT_BRANCH=$GITHUB_HEAD_REF
 
+  echo "::debug::GITHUB_BASE_REF: $TARGET_BRANCH..."
+
   if [[ -z $INPUT_BASE_SHA ]]; then
     if [[ "$INPUT_USE_FORK_POINT" == "true" ]]; then
       echo "::debug::Getting fork point..."
       git fetch --no-tags -u --progress origin "${TARGET_BRANCH}":"${TARGET_BRANCH}" && exit_status=$? || exit_status=$?
       PREVIOUS_SHA=$(git merge-base --fork-point "${TARGET_BRANCH}" "$(git name-rev --name-only "$CURRENT_SHA")") && exit_status=$? || exit_status=$?
+      echo "::debug::Previous SHA: $PREVIOUS_SHA"
     else
       git fetch --no-tags -u --progress origin --depth=1 "${TARGET_BRANCH}":"${TARGET_BRANCH}" && exit_status=$? || exit_status=$?
-      PREVIOUS_SHA=$(git rev-list --no-merges -n 1 "${TARGET_BRANCH}" 2>&1) && exit_status=$? || exit_status=$?
+      PREVIOUS_SHA=$(git rev-list -n 1 "${TARGET_BRANCH}" 2>&1) && exit_status=$? || exit_status=$?
+      echo "::debug::Previous SHA: $PREVIOUS_SHA"
     fi
   else
     git fetch --no-tags -u --progress origin --depth=1 "$INPUT_BASE_SHA" && exit_status=$? || exit_status=$?
     PREVIOUS_SHA=$INPUT_BASE_SHA
     TARGET_BRANCH=$(git name-rev --name-only "$PREVIOUS_SHA" 2>&1) && exit_status=$? || exit_status=$?
+    echo "::debug::Previous SHA: $PREVIOUS_SHA"
+    echo "::debug::Target branch: $TARGET_BRANCH"
   fi
 
   echo "::debug::Verifying commit SHA..."
@@ -94,6 +107,12 @@ else
   fi
 fi
 
+if [[ -n "$PREVIOUS_SHA" && -n "$CURRENT_SHA" && "$PREVIOUS_SHA" == "$CURRENT_SHA" ]]; then
+  echo "::error::Similar commit hashes detected: previous sha: $PREVIOUS_SHA is equivalent to the current sha: $CURRENT_SHA"
+  echo "::error::You seem to be missing 'fetch-depth: 0' or 'fetch-depth: 2'. See https://github.com/tj-actions/changed-files#usage"
+  exit 1
+fi
+
 echo "::set-output name=target_branch::$TARGET_BRANCH"
 echo "::set-output name=current_branch::$CURRENT_BRANCH"
 echo "::set-output name=previous_sha::$PREVIOUS_SHA"