refactor: check for main branch

01-essentials/03-branching-and-merging/setup.ps1

@@ -31,6 +31,19 @@ git init | Out-Null
 git config user.name "Workshop Student"
 git config user.email "student@example.com"
 
+# Detect the default branch name (could be main, master, etc.)
+# First commit creates the branch, so we detect it after that
+$mainBranch = git branch --show-current
+if (-not $mainBranch) {
+    # Fallback: Get default branch name from git config
+    $mainBranch = git config --get init.defaultBranch
+    if (-not $mainBranch) {
+        # Ultimate fallback: use "main"
+        $mainBranch = "main"
+    }
+}
+Write-Host "Default branch detected: $mainBranch" -ForegroundColor Yellow
+
 # ============================================================================
 # Create a realistic project history with multiple merged branches
 # ============================================================================
@@ -96,8 +109,8 @@ Set-Content -Path "login.py" -Value $loginContent
 git add .
 git commit -m "Add password validation" | Out-Null
 
-# Switch back to main and make more commits
-git switch main | Out-Null
+# Switch back to main branch
+git switch $mainBranch | Out-Null
 
 $appContent = @"
 # app.py - Application entry point
@@ -163,8 +176,8 @@ Set-Content -Path "api.py" -Value $apiContent
 git add .
 git commit -m "Add delete endpoint to API" | Out-Null
 
-# Switch back to main and add documentation
-git switch main | Out-Null
+# Switch back to main branch and add documentation
+git switch $mainBranch | Out-Null
 
 $readmeContent = @"
 # My Application
@@ -241,8 +254,22 @@ Set-Content -Path "database.py" -Value $dbContent
 git add .
 git commit -m "Add disconnect method" | Out-Null
 
-# Switch to main and merge
-git switch main | Out-Null
+# Switch to main branch and add another commit (to create divergent history)
+git switch $mainBranch | Out-Null
+
+$configContent = @"
+{
+  "app": {
+    "port": 3000,
+    "debug": false
+  }
+}
+"@
+Set-Content -Path "config.json" -Value $configContent
+git add .
+git commit -m "Add configuration file" | Out-Null
+
+# Merge feature-database (will be three-way merge since main diverged)
 Write-Host "Merging feature-database into main..." -ForegroundColor Green
 git merge feature-database --no-edit | Out-Null
 
@@ -278,7 +305,7 @@ Write-Host "`n=== Setup Complete! ===" -ForegroundColor Green
 Write-Host "`nYour challenge environment is ready in the 'challenge/' directory." -ForegroundColor Cyan
 Write-Host "`nThe repository contains a realistic project history:" -ForegroundColor Yellow
 Write-Host "  - Multiple feature branches (login, api, database)" -ForegroundColor White
-Write-Host "  - All branches have been merged into main" -ForegroundColor White
+Write-Host "  - All branches have been merged into $mainBranch" -ForegroundColor White
 Write-Host "  - View the history: git log --oneline --graph --all" -ForegroundColor White
 Write-Host "`nNext steps:" -ForegroundColor Cyan
 Write-Host "  1. Read the README.md for detailed instructions" -ForegroundColor White