diff --git a/src/scripts/darwin.sh b/src/scripts/darwin.sh
index 9289b1bf..c2caf8f7 100644
--- a/src/scripts/darwin.sh
+++ b/src/scripts/darwin.sh
@@ -10,7 +10,7 @@ self_hosted_helper() {
 # Disable dependency extensions
 disable_dependency_extensions() {
   local extension=$1
-  formula_file="$tap_dir/$ext_tap/Formula/$extension@${version:?}.rb"
+  formula_file="${tap_dir:?}/$ext_tap/Formula/$extension@${version:?}.rb"
   if [ -e "$formula_file" ]; then
     IFS=" " read -r -a dependency_extensions <<< "$(grep -Eo "shivammathur.*@" "$formula_file" | xargs -I {} -n 1 basename '{}' | cut -d '@' -f 1 | tr '\n' ' ')"
     for dependency_extension in "${dependency_extensions[@]}"; do
@@ -33,33 +33,6 @@ disable_extension_helper() {
   echo '' | sudo tee /tmp/extdisabled/"$version"/"$extension" >/dev/null 2>&1
 }
 
-# Function to fetch a brew tap.
-fetch_brew_tap() {
-  tap=$1
-  tap_user=$(dirname "$tap")
-  tap_name=$(basename "$tap")
-  mkdir -p "$tap_dir/$tap_user"
-  get -s -n "" "https://github.com/$tap/archive/master.tar.gz" | sudo tar -xzf - -C "$tap_dir/$tap_user"
-  if [ -d "$tap_dir/$tap_user/$tap_name-master" ]; then
-    sudo mv "$tap_dir/$tap_user/$tap_name-master" "$tap_dir/$tap_user/$tap_name"
-  fi
-}
-
-# Function to add a brew tap.
-add_brew_tap() {
-  tap=$1
-  if ! [ -d "$tap_dir/$tap" ]; then
-    if [ "${runner:?}" = "self-hosted" ]; then
-      brew tap "$tap" >/dev/null 2>&1
-    else
-      fetch_brew_tap "$tap" >/dev/null 2>&1
-      if ! [ -d "$tap_dir/$tap" ]; then
-        brew tap "$tap" >/dev/null 2>&1
-      fi
-    fi
-  fi
-}
-
 # Function to get extension name from brew formula.
 get_extension_from_formula() {
   local formula=$1
@@ -76,7 +49,7 @@ copy_brew_extensions() {
   deps="$(grep -Eo 'depends_on "shivammathur[^"]+' "$formula_file" | cut -d '/' -f 3 | tr '\n' ' ')"
   IFS=' ' read -r -a deps <<< "$formula@$version $deps"
   for dependency in "${deps[@]}"; do
-    extension_file="$brew_prefix/opt/$dependency/$(get_extension_from_formula "${dependency%@*}").so"
+    extension_file="${brew_prefix:?}/opt/$dependency/$(get_extension_from_formula "${dependency%@*}").so"
     [ -e "$extension_file" ] && sudo cp "$extension_file" "$ext_dir"
   done
   sudo find -- "$brew_prefix"/Cellar/"$formula"@"$version" -name "*.dylib" -exec cp {} "$ext_dir" \;
@@ -93,7 +66,7 @@ add_brew_extension() {
   else
     add_brew_tap "$php_tap"
     add_brew_tap "$ext_tap"
-    sudo mv "$tap_dir"/"$ext_tap"/.github/deps/"$formula"/* "$core_repo/Formula/" 2>/dev/null || true
+    sudo mv "$tap_dir"/"$ext_tap"/.github/deps/"$formula"/* "${core_repo:?}/Formula/" 2>/dev/null || true
     update_dependencies >/dev/null 2>&1
     disable_dependency_extensions "$extension" >/dev/null 2>&1
     brew install -f "$ext_tap/$formula@$version" >/dev/null 2>&1
@@ -142,7 +115,7 @@ link_libraries() {
 
 # Patch brew to overwrite packages.
 patch_brew() {
-  formula_installer="$brew_repo"/Library/Homebrew/formula_installer.rb
+  formula_installer="${brew_repo:?}"/Library/Homebrew/formula_installer.rb
   code=" keg.link\(verbose: verbose\?"
   sudo sed -Ei '' "s/$code.*/$code, overwrite: true\)/" "$formula_installer"
   # shellcheck disable=SC2064
@@ -280,12 +253,6 @@ version=${1:-'8.1'}
 ini=${2:-'production'}
 src=${0%/*}/..
 php_formula=shivammathur/php/php@"$version"
-brew_path="$(command -v brew)"
-brew_path_dir="$(dirname "$brew_path")"
-brew_prefix="$brew_path_dir"/..
-brew_repo="$brew_path_dir/$(dirname "$(readlink "$brew_path")")"/..
-tap_dir="$brew_repo"/Library/Taps
-core_repo="$tap_dir"/homebrew/homebrew-core
 scripts="$src"/scripts
 ext_tap=shivammathur/homebrew-extensions
 php_tap=shivammathur/homebrew-php
@@ -298,9 +265,11 @@ export HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK=1
 
 # shellcheck source=.
 . "${scripts:?}"/unix.sh
+. "${scripts:?}"/tools/brew.sh
 . "${scripts:?}"/tools/add_tools.sh
 . "${scripts:?}"/extensions/source.sh
 . "${scripts:?}"/extensions/add_extensions.sh
+configure_brew
 read_env
 self_hosted_setup
 setup_php
diff --git a/src/scripts/tools/brew.sh b/src/scripts/tools/brew.sh
new file mode 100644
index 00000000..11ac8be7
--- /dev/null
+++ b/src/scripts/tools/brew.sh
@@ -0,0 +1,71 @@
+# Function to configure brew constants.
+configure_brew() {
+  brew_path="$(command -v brew)"
+  brew_path_dir="$(dirname "$brew_path")"
+  brew_prefix="$brew_path_dir"/..
+  brew_repo="$brew_path_dir/$(dirname "$(readlink "$brew_path")")"/..
+  tap_dir="$brew_repo"/Library/Taps
+  core_repo="$tap_dir"/homebrew/homebrew-core
+
+  export HOMEBREW_CHANGE_ARCH_TO_ARM=1
+  export HOMEBREW_DEVELOPER=1
+  export HOMEBREW_NO_AUTO_UPDATE=1
+  export HOMEBREW_NO_ENV_HINTS=1
+  export HOMEBREW_NO_INSTALL_CLEANUP=1
+  export HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK=1
+  export brew_path
+  export brew_path_dir
+  export brew_prefix
+  export brew_repo
+  export tap_dir
+  export core_repo
+}
+
+# Function to fetch a brew tap.
+fetch_brew_tap() {
+  tap=$1
+  tap_user=$(dirname "$tap")
+  tap_name=$(basename "$tap")
+  mkdir -p "$tap_dir/$tap_user"
+  branch="$(get -s -n "" "https://api.github.com/repos/$tap" | grep default_branch | cut -d: -f 2 | grep -Eo '[^\", ]+' | tr -d '\n')"
+  get -s -n "" "https://github.com/$tap/archive/$branch.tar.gz" | sudo tar -xzf - -C "$tap_dir/$tap_user"
+  sudo mv "$tap_dir/$tap_user/$tap_name-$branch" "$tap_dir/$tap_user/$tap_name"
+}
+
+# Function to add a brew tap.
+add_brew_tap() {
+  tap=$1
+  if ! [ -d "$tap_dir/$tap" ]; then
+    if [ "${runner:?}" = "self-hosted" ]; then
+      brew tap "$tap" >/dev/null 2>&1
+    else
+      fetch_brew_tap "$tap" >/dev/null 2>&1
+      if ! [ -d "$tap_dir/$tap" ]; then
+        brew tap "$tap" >/dev/null 2>&1
+      fi
+    fi
+  fi
+}
+
+# Function to configure brew constants.
+configure_brew() {
+  brew_path="$(command -v brew)"
+  brew_path_dir="$(dirname "$brew_path")"
+  brew_prefix="$brew_path_dir"/..
+  brew_repo="$brew_path_dir/$(dirname "$(readlink "$brew_path")")"/..
+  tap_dir="$brew_repo"/Library/Taps
+  core_repo="$tap_dir"/homebrew/homebrew-core
+
+  export HOMEBREW_CHANGE_ARCH_TO_ARM=1
+  export HOMEBREW_DEVELOPER=1
+  export HOMEBREW_NO_AUTO_UPDATE=1
+  export HOMEBREW_NO_ENV_HINTS=1
+  export HOMEBREW_NO_INSTALL_CLEANUP=1
+  export HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK=1
+  export brew_path
+  export brew_path_dir
+  export brew_prefix
+  export brew_repo
+  export tap_dir
+  export core_repo
+}