refactor: split out merge strategies from essentials

2026-01-07 21:50:59 +01:00
parent 7fb84560f5
commit df9a2bf7c1
7 changed files with 1164 additions and 177 deletions
--- a/01_essentials/04-merging/README.md
+++ b/01_essentials/04-merging/README.md
@@ -1,13 +1,13 @@
-# Module 04: Merging
+# Module 04: Merging Branches

 ## Learning Objectives

 In this module, you will:
 - Understand what merging means in Git
- Perform a fast-forward merge
- Perform a three-way merge
- Understand when merge commits are created
+- Merge divergent branches together
+- Understand merge commits and their purpose
 - Use `git merge` to combine branches
+- Visualize merge history with `git log --graph`

 ## Challenge

@@ -19,72 +19,217 @@ Run the setup script to create your challenge environment:
 .\setup.ps1
 ```

-This will create a `challenge/` directory with a Git repository that has a main branch and a feature branch ready to merge.
+This will create a `challenge/` directory with a Git repository that has two divergent branches ready to merge.

 ### Your Task

-This challenge has two parts that teach you about the two types of merges in Git:
+You have two branches that have diverged - both `main` and `feature-login` have new commits since they split. Your task is to merge them back together.

-**Part 1: Fast-Forward Merge**
-1. Merge the existing `feature-api` branch into main
-2. Observe that this is a "fast-forward" merge (no merge commit created)
+**Scenario:**
+- You're working on a team project
+- You created a `feature-login` branch to add login functionality
+- While you were working, your teammate added documentation to `main`
+- Now you need to merge your login feature back into main

-**Part 2: Three-Way Merge**
-3. Create a new branch called `feature-ui`
-4. Make commits on the feature-ui branch
-5. Switch back to main and make a commit there too (creates divergence)
-6. Merge feature-ui into main
-7. Observe that this creates a merge commit (three-way merge)
-
-**Suggested Approach:**
+**Steps:**

 1. Navigate to the challenge directory: `cd challenge`
 2. Check current branch: `git branch` (should be on main)
-3. View existing branches: `git branch -a`
-4. Merge feature-api: `git merge feature-api`
-5. View the log: `git log --oneline --graph`
-6. Create feature-ui branch: `git switch -c feature-ui`
-7. Create a new file `ui.py` and commit it
-8. Make another commit on feature-ui (modify ui.py)
-9. Switch back to main: `git switch main`
-10. Make a change on main (modify api.py) and commit it
-11. Merge feature-ui: `git merge feature-ui`
-12. View the merge history: `git log --oneline --graph --all`
+3. View the branch structure: `git log --oneline --graph --all`
+4. Merge the feature-login branch: `git merge feature-login`
+5. View the merge result: `git log --oneline --graph --all`
+6. Examine the merge commit: `git show HEAD`

 > **Important Notes:**
-> - A **fast-forward merge** happens when main hasn't changed since the feature branch was created
-> - A **three-way merge** creates a merge commit when both branches have diverged
-> - You can see merge commits with `git log --merges`
-> - The `--graph` option helps visualize the branch history
-> - After merging, the feature branch still exists but you can delete it with `git branch -d`
+> - When both branches have new commits, Git creates a **merge commit**
+> - The merge commit has TWO parent commits (one from each branch)
+> - Git will open an editor for you to write a merge commit message
+> - You can use the default message or customize it
+> - The `--graph` option helps visualize how branches merged

 ## Key Concepts

- **Merge**: Combining changes from different branches into one branch.
- **Fast-Forward Merge**: When the target branch hasn't changed, Git simply moves the branch pointer forward. No merge commit is created.
- **Three-Way Merge**: When both branches have new commits, Git creates a merge commit that has two parent commits.
- **Merge Commit**: A special commit with two (or more) parent commits, representing the point where branches were merged.
- **Divergent Branches**: Branches that have different commits since they split from a common ancestor.
+### What is Merging?
+
+**Merging** combines changes from different branches into one branch. When you merge, you're telling Git: "Take all the changes from branch X and incorporate them into my current branch."
+
+### Divergent Branches
+
+When two branches have different commits since they split, they are **divergent**:
+
+```
+main:    A---B---C
+              \
+feature:       D---E
+```
+
+- Both branches split from commit B
+- `main` has commit C
+- `feature` has commits D and E
+- They have **diverged** - each has unique work
+
+### The Merge Commit
+
+When you merge divergent branches, Git creates a special **merge commit**:
+
+```
+Before merge:
+main:    A---B---C
+              \
+feature:       D---E
+
+After merge (on main):
+main:    A---B---C-------M
+              \         /
+feature:       D---E---/
+```
+
+**Merge commit (M)** is special because:
+- It has **two parent commits**: C and E
+- It represents the point where branches came back together
+- It contains the combined changes from both branches
+
+### How Git Merges
+
+Git uses a **three-way merge** algorithm:
+
+1. **Common ancestor** (B) - Where the branches split
+2. **Your branch** (C) - Latest commit on main
+3. **Their branch** (E) - Latest commit on feature
+
+Git compares all three to figure out what changed on each branch and combines them intelligently.
+
+## Understanding Merge Output
+
+When you run `git merge feature-login`, you'll see:
+
+```
+Merge made by the 'ort' strategy.
+ login.py | 25 +++++++++++++++++++++++++
+ 1 file changed, 25 insertions(+)
+ create mode 100644 login.py
+```
+
+**What this means:**
+- **"Merge made by the 'ort' strategy"** - Git used its merge algorithm to combine changes
+- The summary shows what files changed in the merge
+- A new merge commit was created
+
+### The Merge Commit Message
+
+Git will open your editor with a default message:
+
+```
+Merge branch 'feature-login'
+
+# Please enter a commit message to explain why this merge is necessary,
+# especially if it merges an updated upstream into a topic branch.
+```
+
+**Tips for merge messages:**
+- The default message is usually fine for simple merges
+- For important merges, explain WHY you're merging
+- Example: "Merge feature-login - adds user authentication system"
+
+## Visualizing Merges
+
+Use `git log --graph` to see the branch structure:
+
+```bash
+git log --oneline --graph --all
+```
+
+**Example output:**
+```
+*   a1b2c3d (HEAD -> main) Merge branch 'feature-login'
+|\
+| * e5f6g7h (feature-login) Implement login validation
+| * h8i9j0k Add login form
+* | k1l2m3n Update README with setup instructions
+|/
+* n4o5p6q Initial project structure
+```
+
+**Reading the graph:**
+- `*` = A commit
+- `|` = Branch line continuing
+- `/` and `\` = Branch splitting or merging
+- `(HEAD -> main)` = Current branch position
+- The merge commit has two lines coming into it

 ## Useful Commands

+### Merging
+
 ```bash
-git merge <branch>           # Merge branch into current branch
-git log --oneline --graph    # View merge history visually
-git log --graph --all        # View all branches and merges
-git log --merges             # Show only merge commits
-git branch -d <branch>       # Delete a merged branch (optional)
+git merge <branch>              # Merge branch into current branch
+git merge --abort               # Cancel a merge in progress
 ```

+### Viewing Merge History
+
+```bash
+git log --oneline --graph       # Simple graph view
+git log --oneline --graph --all # Show all branches
+git log --merges                # Show only merge commits
+git show <commit>               # View details of a merge commit
+```
+
+### Branch Management
+
+```bash
+git branch                      # List local branches
+git branch -a                   # List all branches (including remote)
+git branch -d <branch>          # Delete a merged branch
+```
+
+## Common Questions
+
+### "What if the merge fails?"
+
+Sometimes Git can't automatically merge changes (this is called a **merge conflict**). Don't worry! We'll cover this in the next module (Module 05: Merge Conflicts).
+
+If you see a conflict and want to cancel:
+```bash
+git merge --abort
+```
+
+### "Can I undo a merge?"
+
+Before you've pushed to remote:
+```bash
+git reset --hard HEAD~1    # Undo the merge commit
+```
+
+We'll cover more advanced undoing in later modules.
+
+### "Should I delete the feature branch after merging?"
+
+It's common practice to delete feature branches after merging:
+
+```bash
+git branch -d feature-login    # Safe delete (only works if merged)
+```
+
+This cleans up your branch list. The commits are still in the history - the branch pointer is just removed.
+
+### "What does 'ort strategy' mean?"
+
+Git uses different merge algorithms:
+- **ort** (default in Git 2.34+) - Newer, faster merge algorithm
+- **recursive** (older) - Traditional merge algorithm
+
+You don't need to worry about this - Git picks the best one automatically!
+
 ## Verification

-Once you've completed both merges, verify your solution:
+Once you've completed the merge, verify your solution:

 ```powershell
 .\verify.ps1
 ```

-The verification script will check that you've successfully merged both feature branches and understand the different merge types.
+The verification script will check that you've successfully merged the feature branch.

 ## Need to Start Over?

@@ -95,3 +240,9 @@ If you want to reset the challenge and start fresh:
 ```

 This will remove the challenge directory and run the setup script again, giving you a clean slate.
+
+## What's Next?
+
+Now that you understand basic merging, the next module covers **Merge Conflicts** - what happens when Git can't automatically merge changes and how to resolve them manually.
+
+**Advanced Topic:** In Module 06 (Advanced section), you'll learn about different merge strategies including fast-forward merges and when to use `--no-ff`.
--- a/01_essentials/04-merging/setup.ps1
+++ b/01_essentials/04-merging/setup.ps1
@@ -5,8 +5,7 @@

 .DESCRIPTION
    This script creates a challenge directory with a Git repository that
-    contains a main branch and a feature branch ready to merge. Students
-    will practice both fast-forward and three-way merges.
+    contains two divergent branches ready to merge (three-way merge scenario).
 #>

 Write-Host "`n=== Setting up Module 04 Challenge ===" -ForegroundColor Cyan
@@ -30,99 +29,121 @@ git init | Out-Null
 git config user.name "Workshop Student"
 git config user.email "student@example.com"

-# Commit 1: Initial API file on main
-Write-Host "Creating initial API structure on main..." -ForegroundColor Green
-$apiContent = @"
-# api.py - API module
+# Commit 1: Initial project structure on main
+Write-Host "Creating initial project structure..." -ForegroundColor Green
+$readmeContent = @"
+# My Project

-def api_handler():
-    print("API Handler initialized")
-    return True
+A simple web application project.
+
+## Setup
+
+Coming soon...
 "@
-Set-Content -Path "api.py" -Value $apiContent
+Set-Content -Path "README.md" -Value $readmeContent
+
+$appContent = @"
+# app.py - Main application file
+
+def main():
+    print("Welcome to My App!")
+    pass
+
+if __name__ == "__main__":
+    main()
+"@
+Set-Content -Path "app.py" -Value $appContent

 git add .
-git commit -m "Initial API setup" | Out-Null
+git commit -m "Initial project structure" | Out-Null

-# Commit 2: Add more API functionality on main
-$apiContent = @"
-# api.py - API module
+# Create feature-login branch
+Write-Host "Creating feature-login branch..." -ForegroundColor Green
+git switch -c feature-login | Out-Null

-def api_handler():
-    print("API Handler initialized")
+# Commit on feature-login: Add login module
+Write-Host "Adding login functionality on feature-login..." -ForegroundColor Green
+$loginContent = @"
+# login.py - User login module
+
+def login(username, password):
+    """Authenticate a user."""
+    print(f"Authenticating user: {username}")
+    # TODO: Add actual authentication logic
    return True

-def get_data():
-    print("Fetching data from API...")
-    return {"status": "ok"}
+def logout(username):
+    """Log out a user."""
+    print(f"Logging out user: {username}")
+    return True
 "@
-Set-Content -Path "api.py" -Value $apiContent
+Set-Content -Path "login.py" -Value $loginContent

 git add .
-git commit -m "Add get_data function" | Out-Null
+git commit -m "Add login module" | Out-Null

-# Create feature-api branch and add commits
-Write-Host "Creating feature-api branch..." -ForegroundColor Green
-git checkout -b feature-api 2>$null | Out-Null
+# Second commit on feature-login: Integrate login with app
+$appContent = @"
+# app.py - Main application file
+from login import login, logout

-# Commit on feature-api: Add API routes
-$routesContent = @"
-# api-routes.py - API Routes module
+def main():
+    print("Welcome to My App!")
+    # Add login integration
+    if login("testuser", "password"):
+        print("Login successful!")
+    pass

-def setup_routes():
-    print("Setting up API routes...")
-    routes = {
-        "/api/data": "get_data",
-        "/api/status": "get_status"
-    }
-    return routes
+if __name__ == "__main__":
+    main()
 "@
-Set-Content -Path "api-routes.py" -Value $routesContent
+Set-Content -Path "app.py" -Value $appContent

 git add .
-git commit -m "Add API routes" | Out-Null
-
-# Second commit on feature-api: Enhance routes
-$routesContent = @"
-# api-routes.py - API Routes module
-
-def setup_routes():
-    print("Setting up API routes...")
-    routes = {
-        "/api/data": "get_data",
-        "/api/status": "get_status",
-        "/api/health": "health_check"
-    }
-    return routes
-
-def health_check():
-    return {"healthy": True}
-"@
-Set-Content -Path "api-routes.py" -Value $routesContent
-
-git add .
-git commit -m "Add health check route" | Out-Null
+git commit -m "Integrate login with main app" | Out-Null

 # Switch back to main branch
 Write-Host "Switching back to main branch..." -ForegroundColor Green
-git checkout main 2>$null | Out-Null
+git switch main | Out-Null
+
+# Make a commit on main (creates divergence)
+Write-Host "Adding documentation on main (creates divergence)..." -ForegroundColor Green
+$readmeContent = @"
+# My Project
+
+A simple web application project.
+
+## Setup
+
+1. Install Python 3.8 or higher
+2. Run: python app.py
+
+## Features
+
+- User authentication (coming soon)
+- Data management (coming soon)
+
+## Contributing
+
+Please follow our coding standards when contributing.
+"@
+Set-Content -Path "README.md" -Value $readmeContent
+
+git add .
+git commit -m "Update README with setup instructions" | Out-Null

 # Return to module directory
 Set-Location ..

 Write-Host "`n=== Setup Complete! ===" -ForegroundColor Green
 Write-Host "`nYour challenge environment is ready in the 'challenge/' directory." -ForegroundColor Cyan
-Write-Host "`nYou have:" -ForegroundColor Cyan
-Write-Host "  - A main branch with API code" -ForegroundColor White
-Write-Host "  - A feature-api branch with API routes ready to merge" -ForegroundColor White
+Write-Host "`nScenario: You have two divergent branches!" -ForegroundColor Yellow
+Write-Host "  - main: Has updated documentation" -ForegroundColor White
+Write-Host "  - feature-login: Has new login functionality" -ForegroundColor White
 Write-Host "`nNext steps:" -ForegroundColor Cyan
 Write-Host "  1. cd challenge" -ForegroundColor White
-Write-Host "  2. View branches: git branch -a" -ForegroundColor White
-Write-Host "  3. Merge feature-api: git merge feature-api (fast-forward merge)" -ForegroundColor White
-Write-Host "  4. Create feature-ui branch: git checkout -b feature-ui" -ForegroundColor White
-Write-Host "  5. Make commits on feature-ui" -ForegroundColor White
-Write-Host "  6. Switch back to main and make a commit there" -ForegroundColor White
-Write-Host "  7. Merge feature-ui: git merge feature-ui (three-way merge)" -ForegroundColor White
-Write-Host "  8. View merge history: git log --oneline --graph --all" -ForegroundColor White
-Write-Host "  9. Run '..\verify.ps1' to check your solution" -ForegroundColor White
+Write-Host "  2. View the branch structure: git log --oneline --graph --all" -ForegroundColor White
+Write-Host "  3. Merge feature-login into main: git merge feature-login" -ForegroundColor White
+Write-Host "  4. View the merge result: git log --oneline --graph --all" -ForegroundColor White
+Write-Host "  5. Run '..\verify.ps1' to check your solution" -ForegroundColor White
 Write-Host ""
--- a/01_essentials/04-merging/verify.ps1
+++ b/01_essentials/04-merging/verify.ps1
@@ -8,9 +8,9 @@
    - The challenge directory exists
    - A Git repository exists
    - Currently on main branch
-    - feature-api has been merged into main
-    - feature-ui branch exists and has been merged
-    - A merge commit exists (from three-way merge)
+    - feature-login has been merged into main
+    - A merge commit exists (three-way merge)
+    - Login functionality is present on main
 #>

 Write-Host "`n=== Verifying Module 04 Solution ===" -ForegroundColor Cyan
@@ -38,82 +38,63 @@ if ($currentBranch -eq "main") {
    Write-Host "[PASS] Currently on main branch" -ForegroundColor Green
 } else {
    Write-Host "[FAIL] Not on main branch (currently on: $currentBranch)" -ForegroundColor Red
-    Write-Host "[HINT] Switch to main with: git checkout main" -ForegroundColor Yellow
+    Write-Host "[HINT] Switch to main with: git switch main" -ForegroundColor Yellow
    $allChecksPassed = $false
 }

-# Check if feature-api branch exists
-$featureApiBranch = git branch --list "feature-api" 2>$null
-if ($featureApiBranch) {
-    Write-Host "[PASS] Branch 'feature-api' exists" -ForegroundColor Green
+# Check if feature-login branch exists
+$featureLoginBranch = git branch --list "feature-login" 2>$null
+if ($featureLoginBranch) {
+    Write-Host "[PASS] Branch 'feature-login' exists" -ForegroundColor Green
 } else {
-    Write-Host "[INFO] Branch 'feature-api' not found (may have been deleted after merge)" -ForegroundColor Cyan
+    Write-Host "[INFO] Branch 'feature-login' not found (may have been deleted after merge)" -ForegroundColor Cyan
 }

-# Check if commits from feature-api are in main
-$apiRoutesCommit = git log --all --grep="Add API routes" --oneline 2>$null
-$healthCheckCommit = git log --all --grep="Add health check route" --oneline 2>$null
+# Check if login.py exists (should be on main after merge)
+if (Test-Path "login.py") {
+    Write-Host "[PASS] File 'login.py' exists on main (from feature-login merge)" -ForegroundColor Green
+} else {
+    Write-Host "[FAIL] File 'login.py' not found on main" -ForegroundColor Red
+    Write-Host "[HINT] This file should appear after merging feature-login into main" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}

-if ($apiRoutesCommit -and $healthCheckCommit) {
-    # Check if these commits are in main's history
-    $apiRoutesInMain = git log --grep="Add API routes" --oneline 2>$null
-    $healthCheckInMain = git log --grep="Add health check route" --oneline 2>$null
-
-    if ($apiRoutesInMain -and $healthCheckInMain) {
-        Write-Host "[PASS] Commits from feature-api are merged into main" -ForegroundColor Green
+# Check if app.py contains login integration
+if (Test-Path "app.py") {
+    $appContent = Get-Content "app.py" -Raw
+    if ($appContent -match "login") {
+        Write-Host "[PASS] app.py contains login integration" -ForegroundColor Green
    } else {
-        Write-Host "[FAIL] Commits from feature-api not found in main" -ForegroundColor Red
-        Write-Host "[HINT] Merge feature-api with: git merge feature-api" -ForegroundColor Yellow
+        Write-Host "[FAIL] app.py doesn't contain login integration" -ForegroundColor Red
+        Write-Host "[HINT] After merging, app.py should import and use the login module" -ForegroundColor Yellow
        $allChecksPassed = $false
    }
 } else {
-    Write-Host "[FAIL] Expected commits from feature-api not found" -ForegroundColor Red
-    Write-Host "[HINT] Did you run setup.ps1?" -ForegroundColor Yellow
+    Write-Host "[FAIL] app.py not found" -ForegroundColor Red
    $allChecksPassed = $false
 }

-# Check if api-routes.py exists (should be on main after merge)
-if (Test-Path "api-routes.py") {
-    Write-Host "[PASS] File 'api-routes.py' exists on main (from feature-api merge)" -ForegroundColor Green
-} else {
-    Write-Host "[FAIL] File 'api-routes.py' not found on main" -ForegroundColor Red
-    Write-Host "[HINT] This file should appear after merging feature-api" -ForegroundColor Yellow
-    $allChecksPassed = $false
-}
-
-# Check if feature-ui branch exists
-$featureUiBranch = git branch --list "feature-ui" 2>$null
-if ($featureUiBranch) {
-    Write-Host "[PASS] Branch 'feature-ui' exists" -ForegroundColor Green
-
-    # Check if feature-ui has commits
-    $uiCommitCount = git rev-list main..feature-ui --count 2>$null
-    if ($uiCommitCount -gt 0) {
-        Write-Host "[INFO] Branch 'feature-ui' has $uiCommitCount commit(s)" -ForegroundColor Cyan
-    }
-} else {
-    Write-Host "[FAIL] Branch 'feature-ui' not found" -ForegroundColor Red
-    Write-Host "[HINT] Create feature-ui with: git checkout -b feature-ui" -ForegroundColor Yellow
-    $allChecksPassed = $false
-}
-
-# Check for merge commits (indicates three-way merge happened)
+# Check for merge commit (indicates three-way merge happened)
 $mergeCommits = git log --merges --oneline 2>$null
 if ($mergeCommits) {
-    Write-Host "[PASS] Merge commit(s) found (three-way merge completed)" -ForegroundColor Green
+    Write-Host "[PASS] Merge commit found (three-way merge completed)" -ForegroundColor Green
+
+    # Get the merge commit message
+    $mergeMessage = git log --merges --format=%s -1 2>$null
+    Write-Host "[INFO] Merge commit message: '$mergeMessage'" -ForegroundColor Cyan
 } else {
-    Write-Host "[FAIL] No merge commits found" -ForegroundColor Red
-    Write-Host "[HINT] Create divergence: make commits on both main and feature-ui, then merge" -ForegroundColor Yellow
+    Write-Host "[FAIL] No merge commit found" -ForegroundColor Red
+    Write-Host "[HINT] Merge feature-login into main with: git merge feature-login" -ForegroundColor Yellow
    $allChecksPassed = $false
 }

-# Check if ui.py exists (should be on main after merge)
-if (Test-Path "ui.py") {
-    Write-Host "[PASS] File 'ui.py' exists on main (from feature-ui merge)" -ForegroundColor Green
+# Check if both branches contributed commits (true three-way merge)
+$totalCommits = git rev-list --count HEAD 2>$null
+if ($totalCommits -ge 4) {
+    Write-Host "[PASS] Repository has $totalCommits commits (branches diverged properly)" -ForegroundColor Green
 } else {
-    Write-Host "[FAIL] File 'ui.py' not found on main" -ForegroundColor Red
-    Write-Host "[HINT] Create ui.py on feature-ui branch and merge it into main" -ForegroundColor Yellow
-    $allChecksPassed = $false
+    Write-Host "[WARN] Repository has only $totalCommits commits (expected at least 4)" -ForegroundColor Yellow
+    Write-Host "[INFO] This might still be correct if you deleted commits" -ForegroundColor Cyan
 }

 Set-Location ..
@@ -124,13 +105,14 @@ if ($allChecksPassed) {
    Write-Host "=====================================" -ForegroundColor Green
    Write-Host "   CONGRATULATIONS! CHALLENGE PASSED!" -ForegroundColor Green
    Write-Host "=====================================" -ForegroundColor Green
-    Write-Host "`nYou've successfully learned about Git merging!" -ForegroundColor Cyan
+    Write-Host "`nYou've successfully completed your first branch merge!" -ForegroundColor Cyan
    Write-Host "You now understand:" -ForegroundColor Cyan
-    Write-Host "  - Fast-forward merges (when main hasn't changed)" -ForegroundColor White
-    Write-Host "  - Three-way merges (when branches have diverged)" -ForegroundColor White
-    Write-Host "  - How to use git merge to combine branches" -ForegroundColor White
-    Write-Host "  - Merge commits and how to view them" -ForegroundColor White
-    Write-Host "`nReady for the next module!" -ForegroundColor Green
+    Write-Host "  - How to merge branches with git merge" -ForegroundColor White
+    Write-Host "  - What a merge commit is and why it's created" -ForegroundColor White
+    Write-Host "  - How divergent branches are combined" -ForegroundColor White
+    Write-Host "  - How to visualize merges with git log --graph" -ForegroundColor White
+    Write-Host "`nNext up: Module 05 - Merge Conflicts!" -ForegroundColor Yellow
+    Write-Host "You'll learn what happens when Git can't automatically merge." -ForegroundColor Cyan
    Write-Host ""
 } else {
    Write-Host "`n[SUMMARY] Some checks failed. Review the hints above and try again." -ForegroundColor Red
--- a/03_advanced/06-merge-strategies/README.md
+++ b/03_advanced/06-merge-strategies/README.md
@@ -0,0 +1,448 @@
+# Module 06: Merge Strategies - Fast-Forward vs Three-Way
+
+## Learning Objectives
+
+In this module, you will:
+- Understand the difference between fast-forward and three-way merges
+- Learn when Git automatically chooses each strategy
+- Force specific merge behavior with `--no-ff` and `--ff-only` flags
+- Understand the trade-offs between linear and branched history
+- Make informed decisions about merge strategies for different workflows
+
+## Prerequisites
+
+Before starting this module, you should have completed:
+- Module 03: Branching Basics
+- Module 04: Merging Branches
+
+## Challenge
+
+### Setup
+
+Run the setup script to create your challenge environment:
+
+```powershell
+.\setup.ps1
+```
+
+This will create a `challenge/` directory with scenarios for both fast-forward and three-way merges.
+
+### Your Task
+
+You'll experiment with both types of merges and learn how to control Git's merge behavior.
+
+**Part 1: Fast-Forward Merge**
+1. Merge `feature-fast-forward` into main
+2. Observe Git's "Fast-forward" message
+3. Examine the linear history
+
+**Part 2: Three-Way Merge**
+4. Merge `feature-divergent` into main
+5. Observe Git creates a merge commit
+6. Examine the branched history
+
+**Part 3: Force Merge Commit**
+7. Merge `feature-optional` into main using `--no-ff`
+8. Compare with the fast-forward from Part 1
+
+**Steps:**
+
+1. Navigate to the challenge directory: `cd challenge`
+2. View all branches: `git branch -a`
+3. View the current graph: `git log --oneline --graph --all`
+4. Merge feature-fast-forward: `git merge feature-fast-forward`
+5. Check the log: `git log --oneline --graph`
+6. Merge feature-divergent: `git merge feature-divergent`
+7. Check the log: `git log --oneline --graph --all`
+8. Merge feature-optional with --no-ff: `git merge --no-ff feature-optional`
+9. Compare the results: `git log --oneline --graph --all`
+
+> **Key Questions to Consider:**
+> - Which merges created merge commits?
+> - Which merge kept a linear history?
+> - How does `--no-ff` change Git's behavior?
+> - When would you prefer each approach?
+
+## Understanding Merge Strategies
+
+### Fast-Forward Merge
+
+A **fast-forward merge** happens when the target branch (e.g., `main`) hasn't changed since the feature branch was created. Git simply "fast-forwards" the branch pointer to the latest commit on the feature branch.
+
+**Before the merge:**
+```
+main:    A---B
+              \
+feature:       C---D
+```
+
+In this scenario:
+- Commit B is where `feature` branched off from `main`
+- Commits C and D are new commits on the `feature` branch
+- `main` has NO new commits since the branch split
+- The history is **linear** (straight line from A to D)
+
+**After `git merge feature` (on main):**
+```
+main:    A---B---C---D
+                     ↑
+                  feature
+```
+
+**What happened:**
+- Git moved the `main` pointer forward to commit D
+- NO merge commit was created
+- The history remains linear (a straight line)
+- Both `main` and `feature` now point to the same commit (D)
+
+**Command:**
+```bash
+git switch main
+git merge feature-fast-forward
+```
+
+**Output you'll see:**
+```
+Updating abc123..def456
+Fast-forward
+ new-feature.py | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+```
+
+**Notice the "Fast-forward" message!**
+
+**Characteristics:**
+- ✅ Keeps history linear and clean
+- ✅ Simpler to read in `git log`
+- ✅ No extra merge commit
+- ❌ Loses visibility that work was done on a branch
+- ❌ Harder to revert entire features at once
+
+---
+
+### Three-Way Merge
+
+A **three-way merge** happens when BOTH branches have new commits since they diverged. Git must combine changes from both branches, which creates a special merge commit.
+
+**Before the merge:**
+```
+main:    A---B---C---E
+              \
+feature:       D---F
+```
+
+In this scenario:
+- Commit B is where `feature` branched off from `main`
+- Commits C and E are new commits on `main`
+- Commits D and F are new commits on `feature`
+- The branches have **diverged** (both have unique commits)
+
+**After `git merge feature` (on main):**
+```
+main:    A---B---C---E---M
+              \         /
+feature:       D---F---/
+```
+
+**What happened:**
+- Git created a new **merge commit** (M)
+- Commit M has TWO parent commits: E (from main) and F (from feature)
+- The merge commit combines changes from both branches
+- The history shows the branches converging
+
+**Why it's called "three-way":**
+Git uses THREE commits to perform the merge:
+1. **Commit B** - The common ancestor (where branches split)
+2. **Commit E** - The latest commit on `main`
+3. **Commit F** - The latest commit on `feature`
+
+Git compares all three to figure out what changed on each branch and how to combine them.
+
+**Command:**
+```bash
+git switch main
+git merge feature-divergent
+```
+
+**Output you'll see:**
+```
+Merge made by the 'ort' strategy.
+ feature-code.py | 5 +++++
+ 1 file changed, 5 insertions(+)
+```
+
+**Notice it says "Merge made by the 'ort' strategy" instead of "Fast-forward"!**
+
+**Characteristics:**
+- ✅ Preserves feature branch history
+- ✅ Shows when features were merged
+- ✅ Easier to revert entire features (revert the merge commit)
+- ✅ Clear visualization in git log --graph
+- ❌ Creates more commits (merge commits)
+- ❌ History can become complex with many merges
+
+---
+
+### When Does Each Type Happen?
+
+| Situation | Merge Type | Merge Commit? | Git's Behavior |
+|-----------|------------|---------------|----------------|
+| Target branch (main) has NO new commits | Fast-Forward | ❌ No | Automatic |
+| Target branch (main) HAS new commits | Three-Way | ✅ Yes | Automatic |
+| You use `--no-ff` flag | Three-Way | ✅ Yes | Forced |
+| You use `--ff-only` flag | Fast-Forward | ❌ No | Fails if not possible |
+
+**Git chooses automatically** based on the branch state, but you can override this behavior!
+
+---
+
+## Controlling Merge Behavior
+
+### Force a Merge Commit with `--no-ff`
+
+Even if a fast-forward is possible, you can force Git to create a merge commit:
+
+```bash
+git merge --no-ff feature-optional
+```
+
+**Before (fast-forward would be possible):**
+```
+main:    A---B
+              \
+feature:       C---D
+```
+
+**After `git merge --no-ff feature` (on main):**
+```
+main:    A---B-------M
+              \     /
+feature:       C---D
+```
+
+Notice that even though main didn't change, a merge commit (M) was created!
+
+**When to use `--no-ff`:**
+- ✅ When you want to preserve the feature branch in history
+- ✅ For important features that might need to be reverted
+- ✅ In team workflows where you want to see when features were merged
+- ✅ When following a branching model like Git Flow
+
+**Example:**
+```bash
+# You've finished a major feature on feature-auth
+git switch main
+git merge --no-ff feature-auth -m "Merge feature-auth: Add user authentication system"
+```
+
+This creates a clear marker in history showing when and what was merged.
+
+---
+
+### Require Fast-Forward with `--ff-only`
+
+You can make Git fail the merge if a fast-forward isn't possible:
+
+```bash
+git merge --ff-only feature-branch
+```
+
+**What happens:**
+- ✅ If fast-forward is possible, Git merges
+- ❌ If branches have diverged, Git refuses to merge
+
+**Output when it fails:**
+```
+fatal: Not possible to fast-forward, aborting.
+```
+
+**When to use `--ff-only`:**
+- ✅ When you want to keep history strictly linear
+- ✅ To ensure you rebase before merging
+- ✅ In workflows that prohibit merge commits
+
+**Example workflow:**
+```bash
+# Try to merge
+git merge --ff-only feature-branch
+
+# If it fails, rebase first
+git switch feature-branch
+git rebase main
+git switch main
+git merge --ff-only feature-branch  # Now it works!
+```
+
+---
+
+## Visualizing the Difference
+
+### Linear History (Fast-Forward)
+
+```bash
+git log --oneline --graph
+```
+
+```
+* d1e2f3g (HEAD -> main, feature) Add feature C
+* a4b5c6d Add feature B
+* 7e8f9g0 Add feature A
+* 1a2b3c4 Initial commit
+```
+
+Notice the straight line! No branching visible.
+
+---
+
+### Branched History (Three-Way Merge)
+
+```bash
+git log --oneline --graph --all
+```
+
+```
+*   m1e2r3g (HEAD -> main) Merge branch 'feature'
+|\
+| * f4e5a6t (feature) Add feature implementation
+| * u7r8e9s Feature setup
+* | a1b2c3d Update documentation on main
+|/
+* 0i1n2i3t Initial commit
+```
+
+Notice the branching pattern! You can see:
+- Where the branch split (`|/`)
+- Commits on each branch (`|`)
+- Where branches merged (`*   merge commit`)
+
+---
+
+## Decision Guide: Which Strategy to Use?
+
+### Use Fast-Forward When:
+- ✅ Working on personal projects
+- ✅ Want simplest, cleanest history
+- ✅ Small changes or bug fixes
+- ✅ Don't need to track feature branches
+- ✅ History readability is top priority
+
+### Use Three-Way Merge (or force with --no-ff) When:
+- ✅ Working in teams
+- ✅ Want to preserve feature context
+- ✅ Need to revert features as units
+- ✅ Following Git Flow or similar workflow
+- ✅ Important to see when features were integrated
+
+### Force Fast-Forward (--ff-only) When:
+- ✅ Enforcing rebase workflow
+- ✅ Maintaining strictly linear history
+- ✅ Integration branch requires clean history
+
+---
+
+## Comparison Table
+
+| Aspect | Fast-Forward | Three-Way |
+|--------|-------------|-----------|
+| **When it happens** | Target branch unchanged | Both branches have new commits |
+| **Merge commit created?** | ❌ No | ✅ Yes |
+| **History appearance** | Linear | Branched |
+| **Command output** | "Fast-forward" | "Merge made by..." |
+| **Git log --graph** | Straight line | Fork and merge pattern |
+| **Can revert entire feature?** | ❌ No (must revert each commit) | ✅ Yes (revert merge commit) |
+| **Force it** | `--ff-only` | `--no-ff` |
+| **Best for** | Solo work, small changes | Team work, features |
+
+---
+
+## Useful Commands
+
+### Merging with Strategy Control
+
+```bash
+git merge <branch>              # Let Git decide automatically
+git merge --no-ff <branch>      # Force a merge commit
+git merge --ff-only <branch>    # Only merge if fast-forward possible
+git merge --abort               # Cancel a merge in progress
+```
+
+### Viewing Different Merge Types
+
+```bash
+# See all merges
+git log --merges                # Only merge commits
+git log --no-merges             # Hide merge commits
+
+# Visualize history
+git log --oneline --graph       # See branch structure
+git log --oneline --graph --all # Include all branches
+git log --first-parent          # Follow only main branch line
+
+# Check if merge would be fast-forward
+git merge-base main feature     # Find common ancestor
+git log main..feature           # See commits unique to feature
+```
+
+### Configuring Default Behavior
+
+```bash
+# Disable fast-forward by default
+git config merge.ff false       # Always create merge commits
+
+# Only allow fast-forward
+git config merge.ff only        # Refuse non-fast-forward merges
+
+# Reset to default
+git config --unset merge.ff
+```
+
+---
+
+## Common Patterns in the Wild
+
+### GitHub Flow (Simple)
+- Use fast-forward when possible
+- Short-lived feature branches
+- Merge to main frequently
+
+### Git Flow (Structured)
+- Always use `--no-ff` for features
+- Preserve branch history
+- Complex release management
+
+### Rebase Workflow
+- Always use `--ff-only`
+- Rebase before merging
+- Strictly linear history
+
+---
+
+## Verification
+
+Once you've completed all three merges, verify your solution:
+
+```powershell
+.\verify.ps1
+```
+
+The verification script will check that you've experienced both types of merges and used the `--no-ff` flag.
+
+## Need to Start Over?
+
+If you want to reset the challenge and start fresh:
+
+```powershell
+.\reset.ps1
+```
+
+This will remove the challenge directory and run the setup script again, giving you a clean slate.
+
+## What's Next?
+
+Now that you understand merge strategies, you can make informed decisions about your workflow. Consider:
+
+- **For personal projects:** Fast-forward merges keep history simple
+- **For team projects:** Three-way merges preserve context
+- **For open source:** Follow the project's contribution guidelines
+
+The best strategy depends on your team's needs and workflow!
--- a/03_advanced/06-merge-strategies/reset.ps1
+++ b/03_advanced/06-merge-strategies/reset.ps1
@@ -0,0 +1,24 @@
+#!/usr/bin/env pwsh
+<#
+.SYNOPSIS
+    Resets the Module 06 challenge environment.
+
+.DESCRIPTION
+    This script removes the challenge directory and re-runs the setup script
+    to give you a fresh start.
+#>
+
+Write-Host "`n=== Resetting Module 06 Challenge ===" -ForegroundColor Cyan
+
+# Remove challenge directory if it exists
+if (Test-Path "challenge") {
+    Write-Host "Removing existing challenge directory..." -ForegroundColor Yellow
+    Remove-Item -Recurse -Force "challenge"
+    Write-Host "Challenge directory removed." -ForegroundColor Green
+} else {
+    Write-Host "No challenge directory found to remove." -ForegroundColor Yellow
+}
+
+# Run setup script
+Write-Host "`nRunning setup script..." -ForegroundColor Cyan
+& "./setup.ps1"
--- a/03_advanced/06-merge-strategies/setup.ps1
+++ b/03_advanced/06-merge-strategies/setup.ps1
@@ -0,0 +1,221 @@
+#!/usr/bin/env pwsh
+<#
+.SYNOPSIS
+    Sets up the Module 06 challenge environment for learning merge strategies.
+
+.DESCRIPTION
+    This script creates a challenge directory with a Git repository that
+    contains scenarios for both fast-forward and three-way merges, allowing
+    students to compare different merge strategies.
+#>
+
+Write-Host "`n=== Setting up Module 06 Challenge ===" -ForegroundColor Cyan
+
+# Remove existing challenge directory if it exists
+if (Test-Path "challenge") {
+    Write-Host "Removing existing challenge directory..." -ForegroundColor Yellow
+    Remove-Item -Recurse -Force "challenge"
+}
+
+# Create fresh challenge directory
+Write-Host "Creating challenge directory..." -ForegroundColor Green
+New-Item -ItemType Directory -Path "challenge" | Out-Null
+Set-Location "challenge"
+
+# Initialize Git repository
+Write-Host "Initializing Git repository..." -ForegroundColor Green
+git init | Out-Null
+
+# Configure git for this repository
+git config user.name "Workshop Student"
+git config user.email "student@example.com"
+
+# ========================================
+# Scenario 1: Fast-Forward Merge Setup
+# ========================================
+
+Write-Host "Setting up fast-forward merge scenario..." -ForegroundColor Green
+
+# Commit 1: Initial structure on main
+$appContent = @"
+# app.py - Main application
+
+def main():
+    print("Application started")
+    pass
+
+if __name__ == "__main__":
+    main()
+"@
+Set-Content -Path "app.py" -Value $appContent
+
+git add .
+git commit -m "Initial application structure" | Out-Null
+
+# Create feature-fast-forward branch (main won't change after this)
+git switch -c feature-fast-forward | Out-Null
+
+# Commit on feature-fast-forward
+$utilsContent = @"
+# utils.py - Utility functions
+
+def format_string(text):
+    """Format a string to title case."""
+    return text.title()
+
+def validate_input(text):
+    """Validate user input."""
+    return text and len(text) > 0
+"@
+Set-Content -Path "utils.py" -Value $utilsContent
+
+git add .
+git commit -m "Add utility functions" | Out-Null
+
+# Second commit on feature-fast-forward
+$utilsContent = @"
+# utils.py - Utility functions
+
+def format_string(text):
+    """Format a string to title case."""
+    return text.title()
+
+def validate_input(text):
+    """Validate user input."""
+    return text and len(text) > 0
+
+def sanitize_input(text):
+    """Remove dangerous characters from input."""
+    return text.replace("<", "").replace(">", "")
+"@
+Set-Content -Path "utils.py" -Value $utilsContent
+
+git add .
+git commit -m "Add input sanitization" | Out-Null
+
+# ========================================
+# Scenario 2: Three-Way Merge Setup
+# ========================================
+
+Write-Host "Setting up three-way merge scenario..." -ForegroundColor Green
+
+# Switch back to main
+git switch main | Out-Null
+
+# Create feature-divergent branch
+git switch -c feature-divergent | Out-Null
+
+# Commit on feature-divergent
+$authContent = @"
+# auth.py - Authentication module
+
+def authenticate(username, password):
+    """Authenticate a user."""
+    print(f"Authenticating: {username}")
+    # TODO: Implement actual authentication
+    return True
+"@
+Set-Content -Path "auth.py" -Value $authContent
+
+git add .
+git commit -m "Add authentication module" | Out-Null
+
+# Second commit on feature-divergent
+$authContent = @"
+# auth.py - Authentication module
+
+def authenticate(username, password):
+    """Authenticate a user."""
+    print(f"Authenticating: {username}")
+    # TODO: Implement actual authentication
+    return True
+
+def check_permissions(user, resource):
+    """Check if user has permission for resource."""
+    print(f"Checking permissions for {user}")
+    return True
+"@
+Set-Content -Path "auth.py" -Value $authContent
+
+git add .
+git commit -m "Add permission checking" | Out-Null
+
+# Switch back to main and make a commit (creates divergence)
+git switch main | Out-Null
+
+$readmeContent = @"
+# My Application
+
+A Python application with utilities and authentication.
+
+## Features
+
+- String formatting and validation
+- User authentication
+- Permission management
+
+## Setup
+
+1. Install Python 3.8+
+2. Run: python app.py
+"@
+Set-Content -Path "README.md" -Value $readmeContent
+
+git add .
+git commit -m "Add README documentation" | Out-Null
+
+# ========================================
+# Scenario 3: Optional Fast-Forward for --no-ff
+# ========================================
+
+Write-Host "Setting up --no-ff demonstration scenario..." -ForegroundColor Green
+
+# Create feature-optional branch (main won't change after this)
+git switch -c feature-optional | Out-Null
+
+# Commit on feature-optional
+$configContent = @"
+# config.py - Configuration settings
+
+DEBUG_MODE = False
+LOG_LEVEL = "INFO"
+DATABASE_URL = "sqlite:///app.db"
+"@
+Set-Content -Path "config.py" -Value $configContent
+
+git add .
+git commit -m "Add configuration module" | Out-Null
+
+# Switch back to main
+git switch main | Out-Null
+
+# Return to module directory
+Set-Location ..
+
+Write-Host "`n=== Setup Complete! ===" -ForegroundColor Green
+Write-Host "`nYour challenge environment is ready in the 'challenge/' directory." -ForegroundColor Cyan
+Write-Host "`nYou have THREE scenarios set up:" -ForegroundColor Yellow
+Write-Host "`n  Scenario 1: Fast-Forward Merge" -ForegroundColor White
+Write-Host "    Branch: feature-fast-forward" -ForegroundColor Cyan
+Write-Host "    Status: main has NOT changed since branch was created" -ForegroundColor Cyan
+Write-Host "    Result: Will fast-forward (no merge commit)" -ForegroundColor Green
+Write-Host "`n  Scenario 2: Three-Way Merge" -ForegroundColor White
+Write-Host "    Branch: feature-divergent" -ForegroundColor Cyan
+Write-Host "    Status: BOTH main and branch have new commits" -ForegroundColor Cyan
+Write-Host "    Result: Will create merge commit" -ForegroundColor Green
+Write-Host "`n  Scenario 3: Force Merge Commit" -ForegroundColor White
+Write-Host "    Branch: feature-optional" -ForegroundColor Cyan
+Write-Host "    Status: Could fast-forward, but we'll use --no-ff" -ForegroundColor Cyan
+Write-Host "    Result: Will create merge commit even though fast-forward is possible" -ForegroundColor Green
+Write-Host "`nNext steps:" -ForegroundColor Cyan
+Write-Host "  1. cd challenge" -ForegroundColor White
+Write-Host "  2. View initial state: git log --oneline --graph --all" -ForegroundColor White
+Write-Host "  3. Merge fast-forward: git merge feature-fast-forward" -ForegroundColor White
+Write-Host "  4. View result: git log --oneline --graph" -ForegroundColor White
+Write-Host "  5. Merge divergent: git merge feature-divergent" -ForegroundColor White
+Write-Host "  6. View result: git log --oneline --graph --all" -ForegroundColor White
+Write-Host "  7. Merge with --no-ff: git merge --no-ff feature-optional" -ForegroundColor White
+Write-Host "  8. View final result: git log --oneline --graph --all" -ForegroundColor White
+Write-Host "  9. Compare all three merges!" -ForegroundColor White
+Write-Host " 10. Run '..\verify.ps1' to check your solution" -ForegroundColor White
+Write-Host ""
--- a/03_advanced/06-merge-strategies/verify.ps1
+++ b/03_advanced/06-merge-strategies/verify.ps1
@@ -0,0 +1,140 @@
+#!/usr/bin/env pwsh
+<#
+.SYNOPSIS
+    Verifies the Module 06 challenge solution.
+
+.DESCRIPTION
+    This script checks that:
+    - The challenge directory exists
+    - A Git repository exists
+    - All three feature branches have been merged
+    - Appropriate merge strategies were used
+    - Student understands the difference between fast-forward and three-way merges
+#>
+
+Write-Host "`n=== Verifying Module 06 Solution ===" -ForegroundColor Cyan
+
+$allChecksPassed = $true
+
+# Check if challenge directory exists
+if (-not (Test-Path "challenge")) {
+    Write-Host "[FAIL] Challenge directory not found. Did you run setup.ps1?" -ForegroundColor Red
+    exit 1
+}
+
+Set-Location "challenge"
+
+# Check if git repository exists
+if (-not (Test-Path ".git")) {
+    Write-Host "[FAIL] Not a git repository. Did you run setup.ps1?" -ForegroundColor Red
+    Set-Location ..
+    exit 1
+}
+
+# Check current branch is main
+$currentBranch = git branch --show-current 2>$null
+if ($currentBranch -eq "main") {
+    Write-Host "[PASS] Currently on main branch" -ForegroundColor Green
+} else {
+    Write-Host "[FAIL] Not on main branch (currently on: $currentBranch)" -ForegroundColor Red
+    Write-Host "[HINT] Switch to main with: git switch main" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}
+
+# Check 1: Fast-Forward Merge - utils.py should exist
+if (Test-Path "utils.py") {
+    Write-Host "[PASS] utils.py exists (feature-fast-forward merged)" -ForegroundColor Green
+} else {
+    Write-Host "[FAIL] utils.py not found" -ForegroundColor Red
+    Write-Host "[HINT] Merge feature-fast-forward: git merge feature-fast-forward" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}
+
+# Check 2: Three-Way Merge - auth.py should exist
+if (Test-Path "auth.py") {
+    Write-Host "[PASS] auth.py exists (feature-divergent merged)" -ForegroundColor Green
+} else {
+    Write-Host "[FAIL] auth.py not found" -ForegroundColor Red
+    Write-Host "[HINT] Merge feature-divergent: git merge feature-divergent" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}
+
+# Check 3: --no-ff Merge - config.py should exist
+if (Test-Path "config.py") {
+    Write-Host "[PASS] config.py exists (feature-optional merged)" -ForegroundColor Green
+} else {
+    Write-Host "[FAIL] config.py not found" -ForegroundColor Red
+    Write-Host "[HINT] Merge feature-optional: git merge --no-ff feature-optional" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}
+
+# Check for merge commits
+$mergeCommits = git log --merges --oneline 2>$null
+$mergeCount = ($mergeCommits | Measure-Object -Line).Lines
+
+if ($mergeCount -ge 2) {
+    Write-Host "[PASS] Found $mergeCount merge commit(s)" -ForegroundColor Green
+    Write-Host "[INFO] Expected: 1 from three-way merge + 1 from --no-ff = 2 total" -ForegroundColor Cyan
+} else {
+    Write-Host "[FAIL] Only found $mergeCount merge commit(s), expected at least 2" -ForegroundColor Red
+    Write-Host "[HINT] Make sure to:" -ForegroundColor Yellow
+    Write-Host "       1. Merge feature-divergent (creates merge commit)" -ForegroundColor Yellow
+    Write-Host "       2. Merge feature-optional with --no-ff flag (forces merge commit)" -ForegroundColor Yellow
+    $allChecksPassed = $false
+}
+
+# Provide detailed merge analysis
+Write-Host "`n--- Merge Analysis ---" -ForegroundColor Cyan
+
+# Count total commits
+$totalCommits = git rev-list --count HEAD 2>$null
+Write-Host "[INFO] Total commits on main: $totalCommits" -ForegroundColor Cyan
+
+# List merge commits
+if ($mergeCommits) {
+    Write-Host "[INFO] Merge commits found:" -ForegroundColor Cyan
+    $mergeCommits | ForEach-Object {
+        Write-Host "       $_" -ForegroundColor White
+    }
+}
+
+# Check if branches still exist
+$branches = git branch 2>$null
+Write-Host "[INFO] Existing branches:" -ForegroundColor Cyan
+$branches | ForEach-Object {
+    Write-Host "       $_" -ForegroundColor White
+}
+
+Set-Location ..
+
+# Final summary
+if ($allChecksPassed) {
+    Write-Host "`n" -NoNewline
+    Write-Host "=====================================" -ForegroundColor Green
+    Write-Host "   CONGRATULATIONS! CHALLENGE PASSED!" -ForegroundColor Green
+    Write-Host "=====================================" -ForegroundColor Green
+    Write-Host "`nYou've mastered Git merge strategies!" -ForegroundColor Cyan
+    Write-Host "`nYou now understand:" -ForegroundColor Cyan
+    Write-Host "  - Fast-forward merges (linear history, no merge commit)" -ForegroundColor White
+    Write-Host "  - Three-way merges (divergent branches, creates merge commit)" -ForegroundColor White
+    Write-Host "  - How to force merge commits with --no-ff flag" -ForegroundColor White
+    Write-Host "  - When to use each merge strategy" -ForegroundColor White
+    Write-Host "  - Trade-offs between linear and branched history" -ForegroundColor White
+    Write-Host "`nKey Takeaways:" -ForegroundColor Yellow
+    Write-Host "  - Git chooses the strategy automatically based on branch state" -ForegroundColor Cyan
+    Write-Host "  - Use --no-ff to preserve feature branch history" -ForegroundColor Cyan
+    Write-Host "  - Use --ff-only to enforce linear history" -ForegroundColor Cyan
+    Write-Host "  - Different workflows prefer different strategies" -ForegroundColor Cyan
+    Write-Host "`nNow you can make informed decisions about merge strategies for your projects!" -ForegroundColor Green
+    Write-Host ""
+} else {
+    Write-Host "`n[SUMMARY] Some checks failed. Review the hints above and try again." -ForegroundColor Red
+    Write-Host "[INFO] You can run this verification script as many times as needed." -ForegroundColor Yellow
+    Write-Host ""
+    Write-Host "Quick Reference:" -ForegroundColor Cyan
+    Write-Host "  git merge feature-fast-forward          # Fast-forward merge" -ForegroundColor White
+    Write-Host "  git merge feature-divergent             # Three-way merge" -ForegroundColor White
+    Write-Host "  git merge --no-ff feature-optional      # Force merge commit" -ForegroundColor White
+    Write-Host ""
+    exit 1
+}