Prevent master deletion on delete-merged-branch

helper/git-extra-utility

@@ -5,15 +5,56 @@ git_extra_mktemp() {
     mktemp -t "$(basename "$0")".XXXXXXX
 }
 
+# Determine the default branch name
+#
+# The detection follows this order:
+# 1. Check explicit config 'git-extras.default-branch'
+# 2. Remote HEAD auto-detection
+# 3. Check git's default branch config 'init.defaultBranch' config
+# 4. Common branch detection - Checks if main, master, trunk, development, stable, release, prod, production exist locally
+# 5. Fallback to 'main' as last resort
 git_extra_default_branch() {
-    local extras_default_branch init_default_branch
+    local extras_default_branch init_default_branch remote_default_branch remote_name
+
+    # heck git-extras specific config
     extras_default_branch=$(git config --get git-extras.default-branch)
-    init_default_branch=$(git config --get init.defaultBranch)
     if [ -n "$extras_default_branch" ]; then
         echo "$extras_default_branch"
-    elif [ -n "$init_default_branch" ]; then
+        return
+    fi
+
+    # Auto-detect from remote HEAD
+    # First, try to get a list of remotes
+    local remotes
+    remotes=$(git remote 2>/dev/null)
+    if [ -n "$remotes" ]; then
+        # Try 'origin' first, then use the first available remote
+        for remote_name in origin $remotes; do
+            remote_default_branch=$(git rev-parse --abbrev-ref "$remote_name/HEAD" 2>/dev/null)
+            if [ -n "$remote_default_branch" ] && [ "$remote_default_branch" != "$remote_name/HEAD" ]; then
+                # Strip the remote name prefix (e.g., "origin/master" -> "master")
+                echo "${remote_default_branch#*/}"
+                return
+            fi
+        done
+    fi
+
+    # Check init.defaultBranch config
+    init_default_branch=$(git config --get init.defaultBranch)
+    if [ -n "$init_default_branch" ]; then
         echo "$init_default_branch"
-    else
-        echo "main"
+        return
     fi
+
+    # Check if common default branches exist locally
+    local common_branches="main master trunk development stable release prod production"
+    for branch in $common_branches; do
+        if git show-ref --verify --quiet "refs/heads/$branch"; then
+            echo "$branch"
+            return
+        fi
+    done
+
+    # Final fallback
+    echo "main"
 }

tests/git-extra-utility.bats

@@ -0,0 +1,243 @@
+#!/usr/bin/env bats
+# shellcheck shell=bash
+
+source "$BATS_TEST_DIRNAME/test_util.sh"
+
+setup_file() {
+	test_util.setup_file
+}
+
+setup() {
+	test_util.cd_test
+	test_util.git_init
+
+	# Source the utility file
+	source "$BATS_TEST_DIRNAME/../helper/git-extra-utility"
+}
+
+# Tests for git_extra_mktemp
+@test "git_extra_mktemp: creates a temporary file" {
+	local temp_file
+	temp_file=$(git_extra_mktemp)
+
+	# Check that file was created
+	[[ -e "$temp_file" ]]
+
+	# Cleanup
+	rm -f "$temp_file"
+}
+
+@test "git_extra_mktemp: creates files with unique names" {
+	local temp_file1 temp_file2
+	temp_file1=$(git_extra_mktemp)
+	temp_file2=$(git_extra_mktemp)
+
+	# Check that files are different
+	[[ "$temp_file1" != "$temp_file2" ]]
+
+	# Cleanup
+	rm -f "$temp_file1" "$temp_file2"
+}
+
+@test "git_extra_mktemp: temp files are writable" {
+	local temp_file
+	temp_file=$(git_extra_mktemp)
+
+	# Write to the file
+	echo "test content" > "$temp_file"
+
+	# Verify content
+	[[ "$(cat "$temp_file")" == "test content" ]]
+
+	# Cleanup
+	rm -f "$temp_file"
+}
+
+# Tests for git_extra_default_branch
+@test "git_extra_default_branch: respects git-extras.default-branch config" {
+	git config git-extras.default-branch "custom-branch"
+
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "custom-branch" ]]
+}
+
+@test "git_extra_default_branch: detects from remote HEAD when origin exists" {
+	# Setup a remote with main branch (we're already on main from setup)
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	# Create a bare repo to act as remote
+	local remote_dir="$BATS_TEST_TMPDIR/remote.git"
+	git init --bare "$remote_dir"
+	git remote add origin "$remote_dir"
+	git push -u origin main
+	git remote set-head origin main
+
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "main" ]]
+}
+
+@test "git_extra_default_branch: respects init.defaultBranch config when no remote" {
+	git config init.defaultBranch "develop"
+
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "develop" ]]
+}
+
+@test "git_extra_default_branch: detects 'main' branch when it exists locally" {
+	# We're already on main from setup
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "main" ]]
+}
+
+@test "git_extra_default_branch: detects 'master' branch when it exists locally" {
+	# Create a new repo with master branch
+	cd "$BATS_TEST_TMPDIR"
+	rm -rf test_master
+	mkdir test_master
+	cd test_master
+	git init --initial-branch master
+	git config user.name 'Name'
+	git config user.email '[email protected]'
+	# Need to create a commit so the branch actually exists
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	source "$BATS_TEST_DIRNAME/../helper/git-extra-utility"
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "master" ]]
+}
+
+@test "git_extra_default_branch: prefers 'main' over 'master' when both exist" {
+	# First commit to establish main branch
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	# Create master branch
+	git checkout -b master
+	echo "content2" > file2.txt
+	git add file2.txt
+	git commit -m "master commit"
+
+	# Switch back to main
+	git checkout main
+
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "main" ]]
+}
+
+@test "git_extra_default_branch: detects 'trunk' branch" {
+	# Create a new repo with trunk branch
+	cd "$BATS_TEST_TMPDIR"
+	rm -rf test_trunk
+	mkdir test_trunk
+	cd test_trunk
+	git init --initial-branch trunk
+	git config user.name 'Name'
+	git config user.email '[email protected]'
+	# Need to create a commit so the branch actually exists
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	source "$BATS_TEST_DIRNAME/../helper/git-extra-utility"
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "trunk" ]]
+}
+
+@test "git_extra_default_branch: detects 'development' branch" {
+	# Create a new repo with development branch
+	cd "$BATS_TEST_TMPDIR"
+	rm -rf test_dev
+	mkdir test_dev
+	cd test_dev
+	git init --initial-branch development
+	git config user.name 'Name'
+	git config user.email '[email protected]'
+	# Need to create a commit so the branch actually exists
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	source "$BATS_TEST_DIRNAME/../helper/git-extra-utility"
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "development" ]]
+}
+
+@test "git_extra_default_branch: falls back to 'main' when no branches exist" {
+	# Create a completely empty repo
+	cd "$BATS_TEST_TMPDIR"
+	rm -rf test_empty
+	mkdir test_empty
+	cd test_empty
+	git init
+	git config user.name 'Name'
+	git config user.email '[email protected]'
+
+	source "$BATS_TEST_DIRNAME/../helper/git-extra-utility"
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "main" ]]
+}
+
+@test "git_extra_default_branch: git-extras.default-branch takes precedence over remote HEAD" {
+	# Setup a remote with main branch (we're already on main from setup)
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	local remote_dir="$BATS_TEST_TMPDIR/remote.git"
+	git init --bare "$remote_dir"
+	git remote add origin "$remote_dir"
+	git push -u origin main
+	git remote set-head origin main
+
+	# Set a different default in config
+	git config git-extras.default-branch "custom"
+
+	result=$(git_extra_default_branch)
+
+	# Should use config value, not remote HEAD
+	[[ "$result" == "custom" ]]
+}
+
+@test "git_extra_default_branch: git-extras.default-branch takes precedence over init.defaultBranch" {
+	git config init.defaultBranch "develop"
+	git config git-extras.default-branch "custom"
+
+	result=$(git_extra_default_branch)
+
+	[[ "$result" == "custom" ]]
+}
+
+@test "git_extra_default_branch: remote HEAD takes precedence over init.defaultBranch" {
+	# Setup a remote with main branch
+	echo "content" > file.txt
+	git add file.txt
+	git commit -m "initial commit"
+
+	local remote_dir="$BATS_TEST_TMPDIR/remote.git"
+	git init --bare "$remote_dir"
+	git remote add origin "$remote_dir"
+	git push -u origin main
+	git remote set-head origin main
+
+	# Set a different default in init config
+	git config init.defaultBranch "develop"
+
+	result=$(git_extra_default_branch)
+
+	# Should use remote HEAD, not init.defaultBranch
+	[[ "$result" == "main" ]]
+}