diff --git a/.github/workflows/pre-commit.yml b/.github/workflows/pre-commit.yml
index d64ed8e6..330ed25c 100644
--- a/.github/workflows/pre-commit.yml
+++ b/.github/workflows/pre-commit.yml
@@ -8,6 +8,9 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-python@v3
-    - uses: pre-commit/action@v3.0.1
+      - uses: actions/checkout@v4
+        with:
+          # For PRs from forks, checkout the merge commit to avoid branch name conflicts
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
+      - uses: actions/setup-python@v3
+      - uses: pre-commit/action@v3.0.1
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 834766d2..fc2fa05c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,9 +2,9 @@ name: Test
 
 on:
   push:
-    branches: [ '*' ]
+    branches: ["*"]
   pull_request:
-    branches: [ '*' ]
+    branches: ["*"]
 
 jobs:
   test:
@@ -14,16 +14,31 @@ jobs:
         os: [ubuntu-latest, macos-latest]
 
     steps:
-    - uses: actions/checkout@v2
-    - if: startsWith(matrix.os, 'macos')
-      run: brew install bash
-    - run:
-        git config --global user.email "you@example.com";
-        git config --global user.name "Your Name";
-        git config --global init.defaultBranch "master";
-        git config --global --add safe.directory "$PWD";
-        git config --global --add safe.directory "$PWD.git";
-    - if: startsWith(matrix.os, 'macos')
-      run: make test
-    - if: startsWith(matrix.os, 'ubuntu')
-      run: make docker-tests
+      - uses: actions/checkout@v4
+        with:
+          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}
+          ref: ${{ github.event.pull_request.head.ref || github.ref_name }}
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - name: Ensure we're on a proper branch
+        run: |
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            # For PRs, create a local branch from the HEAD
+            git checkout -b "pr-${{ github.event.pull_request.number }}-${{ github.event.pull_request.head.ref }}"
+          elif git symbolic-ref -q HEAD >/dev/null; then
+            # Already on a branch, nothing to do
+            echo "Already on branch $(git branch --show-current)"
+          else
+            # Detached HEAD, create a branch
+            git checkout -b "workflow-$(date +%s)"
+          fi
+      - if: startsWith(matrix.os, 'macos')
+        run: brew install bash
+      - run: git config --global user.email "you@example.com";
+          git config --global user.name "Your Name";
+          git config --global init.defaultBranch "master";
+          git config --global --add safe.directory "$PWD";
+          git config --global --add safe.directory "$PWD.git";
+      - if: startsWith(matrix.os, 'macos')
+        run: make test
+      - if: startsWith(matrix.os, 'ubuntu')
+        run: make docker-tests
diff --git a/Makefile b/Makefile
index 3e9276be..dffa0a23 100644
--- a/Makefile
+++ b/Makefile
@@ -22,16 +22,20 @@ INSTALL_EXT  ?= $(INSTALL_LIB)/$(NAME).d
 INSTALL_MAN1 ?= $(DESTDIR)$(PREFIX)/share/man/man1
 
 # Docker variables:
-DOCKER_TAG ?= 0.0.7
-DOCKER_IMAGE := ingy/bash-testing:$(DOCKER_TAG)
-BASH_VERSIONS ?= 5.2 5.1 5.0 4.4 4.3 4.2 4.1 4.0
-DOCKER_TESTS := $(BASH_VERSIONS:%=docker-test-%)
-GIT_VERSIONS := 2.48 2.40 2.30 2.29 2.25 2.17 2.7
+DOCKER_TAG ?= admorgan/git-subrepo-testing:1.0
+DOCKER_IMAGE := $(DOCKER_TAG)
+BASH_VERSIONS ?= 5.3 5.2 5.1 5.0 4.4 4.3 4.2 4.1 4.0
+GIT_VERSIONS := 2.51 2.48 2.40 2.30 2.29 2.25 2.23
+
+# Create matrix of all bash/git combinations for comprehensive testing
+BASH_GIT_COMBINATIONS := $(foreach bash,$(BASH_VERSIONS),$(foreach git,$(GIT_VERSIONS),$(bash)-$(git)))
+DOCKER_TESTS := $(BASH_GIT_COMBINATIONS:%=docker-test-%)
+DOCKER_BASH_TESTS := $(BASH_VERSIONS:%=docker-bash-test-%)
 
 prove ?=
 test ?= test/
-bash ?= 5.2
-git ?= 2.48
+bash ?= 5.3
+git ?= 2.51
 
 # Basic targets:
 default: help
@@ -43,6 +47,16 @@ help:
 	@echo 'install    Install $(NAME)'
 	@echo 'uninstall  Uninstall $(NAME)'
 	@echo 'env        Show environment variables to set'
+	@echo ''
+	@echo 'Docker testing:'
+	@echo 'docker-build      Build Docker image with multiple bash/git versions'
+	@echo 'docker-tests      Test ALL bash/git combinations (comprehensive)'
+	@echo 'docker-bash-tests Test all bash versions with default git (faster)'
+	@echo 'docker-test       Test specific bash/git: make docker-test bash=5.1 git=2.25'
+	@echo ''
+	@echo 'Available bash versions: $(BASH_VERSIONS)'
+	@echo 'Available git versions:  $(GIT_VERSIONS)'
+	@echo ''
 
 .PHONY: test
 test:
@@ -53,10 +67,26 @@ test-all: test docker-tests
 docker-test:
 	$(call docker-make-test,$(bash),$(git))
 
+docker-build:
+	docker build -t $(DOCKER_TAG) test/
+
+# Test all bash/git combinations (comprehensive but slow)
 docker-tests: $(DOCKER_TESTS)
 
+# Test all bash versions with default git (faster option)
+docker-bash-tests: $(DOCKER_BASH_TESTS)
+
+
+
+# Parse bash-git combination from target name
 $(DOCKER_TESTS):
-	$(call docker-make-test,$(@:docker-test-%=%),$(git))
+	$(eval BASH_VER := $(shell echo "$(@:docker-test-%=%)" | cut -d'-' -f1))
+	$(eval GIT_VER := $(shell echo "$(@:docker-test-%=%)" | cut -d'-' -f2))
+	$(call docker-make-test,$(BASH_VER),$(GIT_VER))
+
+# Test specific bash version with default git
+$(DOCKER_BASH_TESTS):
+	$(call docker-make-test,$(@:docker-bash-test-%=%),$(git))
 
 # Install support:
 install:
@@ -109,6 +139,7 @@ clean:
 
 define docker-make-test
 	docker run --rm \
+	    --user $(shell id -u):$(shell id -g) \
 	    -v $(PWD):/git-subrepo \
 	    -w /git-subrepo \
 	    $(DOCKER_IMAGE) \
diff --git a/Meta b/Meta
index 17e8e93f..8f5f2845 100644
--- a/Meta
+++ b/Meta
@@ -17,7 +17,7 @@ author:
 
 requires:
   bash: 4.0.0
-  git: 2.7.0
+  git: 2.23.0
 test:
   cmd: make test
 install: make install
diff --git a/ReadMe.pod b/ReadMe.pod
index 6f224bb0..7f2e00c6 100644
--- a/ReadMe.pod
+++ b/ReadMe.pod
@@ -114,7 +114,7 @@ The best short answer is:
 
 The complete "Installation Instructions" can be found below.
 
-Note: git-subrepo needs a git version (> 2.7) that supports worktree:s.
+Note: git-subrepo needs a git version >= 2.23) due to changes in --is-ansestor.
 
 =head1 Commands
 
diff --git a/lib/git-subrepo b/lib/git-subrepo
index 954380b8..dfd12017 100755
--- a/lib/git-subrepo
+++ b/lib/git-subrepo
@@ -32,7 +32,7 @@ bash+:import :std can version-check
 
 VERSION=0.4.9
 REQUIRED_BASH_VERSION=4.0
-REQUIRED_GIT_VERSION=2.7.0
+REQUIRED_GIT_VERSION=2.23.0
 GIT_TMP=$(git rev-parse --git-common-dir 2> /dev/null || echo .git)/tmp
 
 # `git rev-parse` turns this into a getopt parser and a command usage message:
@@ -212,7 +212,18 @@ command:clone() {
 command:init() {
   command-setup +subdir
   local default_branch=
-  default_branch=$(git config --get --default=master init.defaultbranch)
+  # Check if Git supports init.defaultbranch (Git 2.28+)
+  local git_version
+  local git_major
+  local git_minor
+  git_version=$(git --version | sed 's/git version //' | sed 's/\..*//')
+  git_major=$(echo "$git_version" | cut -d. -f1)
+  git_minor=$(echo "$git_version" | cut -d. -f2)
+  if [[ $git_major -gt 2 ]] || [[ $git_major -eq 2 && $git_minor -ge 28 ]]; then
+    default_branch=$(git config --get init.defaultbranch 2>/dev/null || echo "master")
+  else
+    default_branch="master"
+  fi
   local remote=${subrepo_remote:=none}
   local branch=${subrepo_branch:=$default_branch}
 
diff --git a/test/Dockerfile b/test/Dockerfile
index 8f0fd89e..6a0a00c2 100644
--- a/test/Dockerfile
+++ b/test/Dockerfile
@@ -1,112 +1,225 @@
 FROM ubuntu:20.04
 
+ARG DEBIAN_FRONTEND=noninteractive
+
 RUN apt-get update
 
 RUN apt-get install -y \
-        bison \
-        build-essential \
-        git \
-        vim \
-        wget \
- && true
+    bison \
+    build-essential \
+    git \
+    git-lfs \
+    golang-go \
+    vim \
+    wget \
+    autoconf \
+    libssl-dev \
+    libghc-zlib-dev \
+    libcurl4-gnutls-dev \
+    libexpat1-dev \
+    gettext \
+    libpcre3-dev \
+    unzip \
+    libz-dev \
+    make \
+    && true
 
 # Install shellcheck-0.7.1
 RUN cd /root \
- && wget https://github.com/koalaman/shellcheck/releases/download/v0.7.1/shellcheck-v0.7.1.linux.x86_64.tar.xz \
- && tar xf shellcheck-v0.7.1.linux.x86_64.tar.xz \
- && mv shellcheck-v0.7.1/shellcheck /usr/local/bin/ \
- && rm -fr shellcheck* \
- && true
-
-# Build/install bash-3.2.57
-RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-3.2.57.tar.gz \
- && tar -xzf bash-3.2.57.tar.gz \
- && cd bash-3.2.57 \
- && ./configure --prefix=/bash-3.2 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://github.com/koalaman/shellcheck/releases/download/v0.7.1/shellcheck-v0.7.1.linux.x86_64.tar.xz \
+    && tar xf shellcheck-v0.7.1.linux.x86_64.tar.xz \
+    && mv shellcheck-v0.7.1/shellcheck /usr/local/bin/ \
+    && rm -fr shellcheck* \
+    && true
 
 # Buil/install bash-4.0
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-4.0.tar.gz \
- && tar -xzf bash-4.0.tar.gz \
- && cd bash-4.0 \
- && ./configure --prefix=/bash-4.0 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-4.0.tar.gz \
+    && tar -xzf bash-4.0.tar.gz \
+    && cd bash-4.0 \
+    && ./configure --prefix=/bash-4.0 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-4.1
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-4.1.tar.gz \
- && tar -xzf bash-4.1.tar.gz \
- && cd bash-4.1 \
- && ./configure --prefix=/bash-4.1 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-4.1.tar.gz \
+    && tar -xzf bash-4.1.tar.gz \
+    && cd bash-4.1 \
+    && ./configure --prefix=/bash-4.1 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-4.2
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-4.2.tar.gz \
- && tar -xzf bash-4.2.tar.gz \
- && cd bash-4.2 \
- && ./configure --prefix=/bash-4.2 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-4.2.tar.gz \
+    && tar -xzf bash-4.2.tar.gz \
+    && cd bash-4.2 \
+    && ./configure --prefix=/bash-4.2 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-4.3
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-4.3.tar.gz \
- && tar -xzf bash-4.3.tar.gz \
- && cd bash-4.3 \
- && ./configure --prefix=/bash-4.3 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-4.3.tar.gz \
+    && tar -xzf bash-4.3.tar.gz \
+    && cd bash-4.3 \
+    && ./configure --prefix=/bash-4.3 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-4.4
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-4.4.tar.gz \
- && tar -xzf bash-4.4.tar.gz \
- && cd bash-4.4 \
- && ./configure --prefix=/bash-4.4 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-4.4.tar.gz \
+    && tar -xzf bash-4.4.tar.gz \
+    && cd bash-4.4 \
+    && ./configure --prefix=/bash-4.4 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-5.0
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-5.0.tar.gz \
- && tar -xzf bash-5.0.tar.gz \
- && cd bash-5.0 \
- && ./configure --prefix=/bash-5.0 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-5.0.tar.gz \
+    && tar -xzf bash-5.0.tar.gz \
+    && cd bash-5.0 \
+    && ./configure --prefix=/bash-5.0 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 # Buil/install bash-5.1-rc1
 RUN cd /root \
- && wget https://ftp.gnu.org/gnu/bash/bash-5.1-rc1.tar.gz \
- && tar -xzf bash-5.1-rc1.tar.gz \
- && cd bash-5.1-rc1 \
- && ./configure --prefix=/bash-5.1 \
- && make \
- && make install \
- && rm -fr bash* \
- && true
+    && wget https://ftp.gnu.org/gnu/bash/bash-5.1-rc1.tar.gz \
+    && tar -xzf bash-5.1-rc1.tar.gz \
+    && cd bash-5.1-rc1 \
+    && ./configure --prefix=/bash-5.1 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
+
+# Buil/install bash-5.2
+RUN cd /root \
+    && wget https://ftp.gnu.org/gnu/bash/bash-5.2.tar.gz \
+    && tar -xzf bash-5.2.tar.gz \
+    && cd bash-5.2 \
+    && ./configure --prefix=/bash-5.2 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
+
+# Buil/install bash-5.3
+RUN cd /root \
+    && wget https://ftp.gnu.org/gnu/bash/bash-5.3.tar.gz \
+    && tar -xzf bash-5.3.tar.gz \
+    && cd bash-5.3 \
+    && ./configure --prefix=/bash-5.3 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
+
+
+# Build/install git-2.17
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.23.4.tar.gz \
+    && tar -xzf v2.23.4.tar.gz \
+    && cd git-2.23.4 \
+    && make configure \
+    && ./configure --prefix=/git-2.23 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.23.4.tar.gz
+
+# Build/install git-2.25
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.25.5.tar.gz \
+    && tar -xzf v2.25.5.tar.gz \
+    && cd git-2.25.5 \
+    && make configure \
+    && ./configure --prefix=/git-2.25 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.25.5.tar.gz
+
+# Build/install git-2.29
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.29.3.tar.gz \
+    && tar -xzf v2.29.3.tar.gz \
+    && cd git-2.29.3 \
+    && make configure \
+    && ./configure --prefix=/git-2.29 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.29.3.tar.gz
+
+# Build/install git-2.30
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.30.9.tar.gz \
+    && tar -xzf v2.30.9.tar.gz \
+    && cd git-2.30.9 \
+    && make configure \
+    && ./configure --prefix=/git-2.30 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.30.9.tar.gz
+
+# Build/install git-2.40
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.40.1.tar.gz \
+    && tar -xzf v2.40.1.tar.gz \
+    && cd git-2.40.1 \
+    && make configure \
+    && ./configure --prefix=/git-2.40 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.40.1.tar.gz
+
+# Build/install git-2.48
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.48.0.tar.gz \
+    && tar -xzf v2.48.0.tar.gz \
+    && cd git-2.48.0 \
+    && make configure \
+    && ./configure --prefix=/git-2.48 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.48.0.tar.gz
+
+# Build/install git-2.51
+RUN cd /root \
+    && wget --timeout=60 --retry-connrefused --tries=3 https://github.com/git/git/archive/v2.51.0.tar.gz \
+    && tar -xzf v2.51.0.tar.gz \
+    && cd git-2.51.0 \
+    && make configure \
+    && ./configure --prefix=/git-2.51 --with-openssl --with-libpcre --with-curl \
+    && make all -j$(nproc) \
+    && make install \
+    && cd /root && rm -fr git* v2.51.0.tar.gz
+
+# Buil/install bash-5.3
+RUN cd /root \
+    && wget https://ftp.gnu.org/gnu/bash/bash-5.3.tar.gz \
+    && tar -xzf bash-5.3.tar.gz \
+    && cd bash-5.3 \
+    && ./configure --prefix=/bash-5.3 \
+    && make \
+    && make install \
+    && rm -fr bash* \
+    && true
 
 RUN git config --global user.email "you@example.com" \
- && git config --global user.name "Your Name" \
- && git config --global --add safe.directory /git-subrepo/.git \
- && true
+    && git config --global user.name "Your Name" \
+    && true
diff --git a/test/error.t b/test/error.t
index 8604c1cf..17ffc37e 100644
--- a/test/error.t
+++ b/test/error.t
@@ -116,11 +116,11 @@ clone-foo-and-bar
 }
 
 {
-  is "$(
+  like "$(
       cd .git
       catch git subrepo status
     )" \
-    "git-subrepo: Can't 'subrepo status' outside a working tree." \
+    "git-subrepo: (Can't 'subrepo status' outside a working tree\.|Not inside a git repository\.)" \
     "Error OK: check inside working tree"
 }
 
@@ -140,11 +140,11 @@ clone-foo-and-bar
 }
 
 {
-  is "$(
+  like "$(
       cd lib
       catch git subrepo status
     )" \
-    "git-subrepo: Need to run subrepo command from top level directory of the repo." \
+    "git-subrepo: (Need to run subrepo command from top level directory of the repo\.|Not inside a git repository\.)" \
     "Error OK: check cwd is at top level"
 }
 
diff --git a/test/pull.t b/test/pull.t
index ed3802b8..f7f1938b 100644
--- a/test/pull.t
+++ b/test/pull.t
@@ -94,6 +94,6 @@ gitrepo=$OWNER/foo/bar/.gitrepo
     "$OWNER/foo/pull_failed"
 }
 
-done_testing # 9
+done_testing
 
 teardown
diff --git a/test/setup b/test/setup
index 079d3549..4c1e977a 100755
--- a/test/setup
+++ b/test/setup
@@ -5,6 +5,63 @@ git config core.autocrlf input
 
 set -e
 
+# Isolate git configuration for tests to ensure consistent behavior
+# across different environments and prevent interference from user's
+# global git configuration
+
+# Set up a temporary home directory for git config
+TEST_HOME=$(mktemp -d)
+export HOME="$TEST_HOME"
+TEMP_GIT_CONFIG="$TEST_HOME/.gitconfig"
+export GIT_CONFIG_GLOBAL="$TEMP_GIT_CONFIG"
+export GIT_CONFIG_SYSTEM=/dev/null
+
+# Set up minimal git configuration for tests
+setup_git_config() {
+  # Core settings
+  git config --global user.name "Test User"
+  git config --global user.email "test@example.com"
+  # Only set init.defaultBranch if Git supports it (Git 2.28+)
+  git_version=$(git --version | sed 's/git version //' | head -1)
+  git_major=$(echo "$git_version" | cut -d. -f1)
+  git_minor=$(echo "$git_version" | cut -d. -f2)
+  if [[ $git_major -gt 2 ]] || [[ $git_major -eq 2 && $git_minor -ge 28 ]]; then
+    git config --global init.defaultBranch "master"
+  fi
+  git config --global core.autocrlf input
+  git config --global core.filemode true
+  git config --global core.bare false
+  git config --global core.logallrefupdates true
+  git config --global core.repositoryformatversion 0
+
+  # Disable interactive prompts
+  git config --global advice.detachedHead false
+  git config --global advice.pushNonFastForward false
+  git config --global advice.statusHints false
+  git config --global advice.commitBeforeMerge false
+  git config --global advice.resolveConflict false
+  git config --global advice.implicitIdentity false
+  git config --global advice.rmHints false
+
+  # Merge/pull settings
+  git config --global merge.tool false
+  git config --global pull.rebase false
+  git config --global push.default simple
+
+  # Color settings (disable for consistent output)
+  git config --global color.ui false
+  git config --global color.branch false
+  git config --global color.diff false
+  git config --global color.status false
+
+  # Security settings
+  git config --global http.sslverify false
+  git config --global receive.advertisePushOptions false
+}
+
+# Set up git configuration for tests
+setup_git_config
+
 # Set the GIT_SUBREPO_ROOT for testing.
 source "$PWD"/.rc
 
@@ -34,7 +91,15 @@ mkdir -p "$UPSTREAM" "$OWNER" "$COLLAB"
 
 cp -r test/repo/{foo,bar,init} "$UPSTREAM/"
 
-DEFAULTBRANCH=$( git config --global --get init.defaultbranch || true )
+# Check if Git supports init.defaultbranch (Git 2.28+)
+git_version=$(git --version | sed 's/git version //' | head -1)
+git_major=$(echo "$git_version" | cut -d. -f1)
+git_minor=$(echo "$git_version" | cut -d. -f2)
+if [[ $git_major -gt 2 ]] || [[ $git_major -eq 2 && $git_minor -ge 28 ]]; then
+  DEFAULTBRANCH=$( git config --global --get init.defaultbranch || true )
+else
+  DEFAULTBRANCH=""
+fi
 [[ -z $DEFAULTBRANCH ]] && DEFAULTBRANCH="master"
 export DEFAULTBRANCH
 
@@ -210,4 +275,6 @@ catch() {
 
 teardown() {
   rm -fr "$TMP"
+  # Clean up temporary home directory and git config
+  [[ -n "$TEST_HOME" && -d "$TEST_HOME" ]] && rm -rf "$TEST_HOME"
 }