refactor: rename 01_essentials to 01-essentials

This commit is contained in:
Bjarke Sporring
2026-01-11 23:05:03 +01:00
parent 8d63b2d22e
commit 5f78245734
54 changed files with 0 additions and 0 deletions

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# Module 05: Git Revert - Safe Undoing
## About This Module
Welcome to Module 05, where you'll learn the **safe, team-friendly way to undo changes** in Git. Unlike destructive commands that erase history, `git revert` creates new commits that undo previous changes while preserving the complete project history.
**Why revert is important:**
- ✅ Safe for shared/pushed commits
- ✅ Preserves complete history and audit trail
- ✅ Transparent to your team
- ✅ Can be undone itself if needed
- ✅ Works with any commit in history
**Key principle:** Revert doesn't erase mistakes—it documents how you fixed them.
## Learning Objectives
By completing this module, you will:
1. Revert regular commits safely while preserving surrounding changes
2. Revert merge commits using the `-m` flag
3. Understand merge commit parent numbering
4. Handle the re-merge problem that occurs after reverting merges
5. Revert multiple commits at once
6. Know when to use revert vs. other undo strategies
## Prerequisites
Before starting this module, you should be comfortable with:
- Creating commits (`git commit`)
- Viewing commit history (`git log`)
- Understanding branches and merging (Module 03)
## Setup
Run the setup script to create the challenge environment:
```powershell
./setup.ps1
```
This creates a `challenge/` directory with three branches demonstrating different revert scenarios:
- `regular-revert` - Basic commit reversion
- `merge-revert` - Merge commit reversion
- `multi-revert` - Multiple commit reversion
## Challenge 1: Reverting a Regular Commit
### Scenario
You're working on a calculator application. A developer added a `divide` function that crashes when dividing by zero. The bug was discovered after subsequent commits were made, so you can't just delete it—you need to revert it while keeping the commits that came after.
### Your Task
1. Navigate to the challenge directory:
```bash
cd challenge
```
2. You should be on the `regular-revert` branch. View the commit history:
```bash
git log --oneline
```
3. Find the commit with the broken divide function (message: "Add broken divide function - needs to be reverted!")
4. Revert that specific commit:
```bash
git revert <commit-hash>
```
5. Git will open your editor for the revert commit message. The default message is fine—save and close.
### What to Observe
After reverting, check:
```bash
# View the new revert commit
git log --oneline
# Check that divide function is gone
cat calculator.py | grep "def divide" # Should return nothing
# Check that modulo function still exists (it came after the bad commit)
cat calculator.py | grep "def modulo" # Should find it
# Check that multiply function still exists (it came before the bad commit)
cat calculator.py | grep "def multiply" # Should find it
```
**Key insight:** Revert creates a new commit that undoes the changes from the target commit, but leaves all other commits intact.
### Understanding the Timeline
```
Before revert:
main.py (initial) → multiply (good) → divide (BAD) → modulo (good)
We want to undo THIS
After revert:
main.py (initial) → multiply (good) → divide (BAD) → modulo (good) → revert divide (new commit)
Removes divide, keeps modulo
```
The revert commit adds a new point in history that undoes the divide changes.
## Challenge 2: Reverting a Merge Commit
### Scenario
Your team merged a `feature-auth` branch that added authentication functionality. After deployment, you discovered the authentication system has critical security issues. You need to revert the entire merge while the security team redesigns the feature.
**This is different from reverting a regular commit!** Merge commits have **two parents**, so you must tell Git which parent to keep.
### Understanding Merge Commit Parents
When you merge a feature branch into main:
```
feature-auth (parent 2)
C---D
/ \
A---B-----M ← Merge commit (has TWO parents)
parent 1 (main)
```
The merge commit `M` has:
- **Parent 1**: The branch you merged INTO (main)
- **Parent 2**: The branch you merged FROM (feature-auth)
When reverting a merge, you must specify which parent to keep using the `-m` flag:
- `-m 1` means "keep parent 1" (main) - **Most common**
- `-m 2` means "keep parent 2" (feature-auth) - Rare
**In practice:** You almost always use `-m 1` to keep the main branch and undo the feature branch changes.
### Your Task
1. Switch to the merge-revert branch:
```bash
git switch merge-revert
```
2. View the commit history and find the merge commit:
```bash
git log --oneline --graph
```
Look for: "Merge feature-auth branch"
3. Revert the merge commit using `-m 1`:
```bash
git revert -m 1 <merge-commit-hash>
```
**Explanation:**
- `-m 1` tells Git to keep parent 1 (main branch)
- This undoes all changes from the feature-auth branch
- Creates a new "revert merge" commit
4. Save the default commit message and check the result:
```bash
# Verify auth.py is gone
ls auth.py # Should not exist
# Verify calculator.py no longer imports auth
cat calculator.py | grep "from auth" # Should return nothing
```
### What Happens Without -m?
If you try to revert a merge commit without the `-m` flag:
```bash
git revert <merge-commit-hash>
# Error: commit <hash> is a merge but no -m option was given
```
Git doesn't know which parent you want to keep, so it refuses to proceed.
### The Re-Merge Problem
**Important gotcha:** After reverting a merge, you **cannot simply re-merge** the same branch!
Here's why:
```
Initial merge:
A---B---M (merged feature-auth)
All changes from feature-auth are now in main
After revert:
A---B---M---R (reverted merge)
Changes removed, but Git remembers they were merged
Attempting to re-merge:
A---B---M---R---M2 (try to merge feature-auth again)
Git thinks: "I already merged these commits,
nothing new to add!" (Empty merge)
```
**Solutions if you need to re-merge:**
1. **Revert the revert** (recommended):
```bash
git revert <revert-commit-hash>
```
This brings back all the feature-auth changes.
2. **Cherry-pick new commits** from the feature branch:
```bash
git cherry-pick <new-commits>
```
3. **Merge with --no-ff** and resolve conflicts manually (advanced).
### When to Revert Merges
Revert merge commits when:
- ✅ Feature causes production issues
- ✅ Need to temporarily remove a feature
- ✅ Discovered critical bugs after merging
- ✅ Security issues require immediate rollback
Don't revert merges when:
- ❌ You just need to fix a small bug (fix it with a new commit instead)
- ❌ You plan to re-merge the same branch soon (use reset if local, or revert-the-revert later)
## Challenge 3: Reverting Multiple Commits
### Scenario
Two separate commits added broken mathematical functions (`square_root` and `logarithm`). Both have critical bugs and need to be removed. You can revert multiple commits at once.
### Your Task
1. Switch to the multi-revert branch:
```bash
git switch multi-revert
```
2. View the commit history:
```bash
git log --oneline
```
Find the two commits:
- "Add broken square_root - REVERT THIS!"
- "Add broken logarithm - REVERT THIS TOO!"
3. Revert both commits in one command:
```bash
git revert <commit-hash-1> <commit-hash-2>
```
**Important:** List commits from **oldest to newest** for cleanest history.
Alternatively, revert them one at a time:
```bash
git revert <commit-hash-1>
git revert <commit-hash-2>
```
4. Git will prompt for a commit message for each revert. Accept the defaults.
5. Verify the result:
```bash
# Check that both bad functions are gone
cat calculator.py | grep "def square_root" # Should return nothing
cat calculator.py | grep "def logarithm" # Should return nothing
# Check that good functions remain
cat calculator.py | grep "def power" # Should find it
cat calculator.py | grep "def absolute" # Should find it
```
### Multi-Revert Strategies
**Reverting a range of commits:**
```bash
# Revert commits from A to B (inclusive)
git revert A^..B
# Example: Revert last 3 commits
git revert HEAD~3..HEAD
```
**Reverting without auto-commit:**
```bash
# Stage revert changes without committing
git revert --no-commit <commit-hash>
# Review changes
git diff --staged
# Commit when ready
git commit
```
This is useful when reverting multiple commits and you want one combined revert commit.
## Verification
Verify your solutions by running the verification script:
```bash
cd .. # Return to module directory
./verify.ps1
```
The script checks that:
- ✅ Revert commits were created (not destructive deletion)
- ✅ Bad code is removed
- ✅ Good code before and after is preserved
- ✅ Merge commits still exist in history
- ✅ Proper use of `-m` flag for merge reverts
## Command Reference
### Basic Revert
```bash
# Revert a specific commit
git revert <commit-hash>
# Revert the most recent commit
git revert HEAD
# Revert the second-to-last commit
git revert HEAD~1
```
### Merge Commit Revert
```bash
# Revert a merge commit (keep parent 1)
git revert -m 1 <merge-commit-hash>
# Revert a merge commit (keep parent 2) - rare
git revert -m 2 <merge-commit-hash>
```
### Multiple Commits
```bash
# Revert multiple specific commits
git revert <hash1> <hash2> <hash3>
# Revert a range of commits (oldest^..newest)
git revert <oldest-hash>^..<newest-hash>
# Revert last 3 commits
git revert HEAD~3..HEAD
```
### Revert Options
```bash
# Revert but don't commit automatically
git revert --no-commit <commit-hash>
# Revert and edit the commit message
git revert --edit <commit-hash>
# Revert without opening editor (use default message)
git revert --no-edit <commit-hash>
# Abort a revert in progress (if conflicts)
git revert --abort
# Continue revert after resolving conflicts
git revert --continue
```
## When to Use Git Revert
Use `git revert` when:
- ✅ **Commits are already pushed** - Safe for shared history
- ✅ **Working in a team** - Transparent to everyone
- ✅ **Need audit trail** - Shows what was undone and why
- ✅ **Public repositories** - Can't rewrite public history
- ✅ **Undoing old commits** - Can revert commits from weeks ago
- ✅ **Production hotfixes** - Safe emergency rollback
**Golden Rule:** If others might have your commits, use revert.
## When NOT to Use Git Revert
Consider alternatives when:
- ❌ **Commits are still local** - Use `git reset` instead (Module 06)
- ❌ **Just want to edit a commit** - Use `git commit --amend`
- ❌ **Haven't pushed yet** - Reset is cleaner for local cleanup
- ❌ **Need to combine commits** - Use interactive rebase
- ❌ **Reverting creates complex conflicts** - Might need manual fix forward
## Revert vs. Reset vs. Rebase
| Command | History | Safety | Use Case |
|---------|---------|--------|----------|
| **revert** | Preserves | ✅ Safe | Undo pushed commits |
| **reset** | Erases | ⚠️ Dangerous | Clean up local commits |
| **rebase** | Rewrites | ⚠️ Dangerous | Polish commit history |
**This module teaches revert.** You'll learn reset in Module 06.
## Handling Revert Conflicts
Sometimes reverting causes conflicts if subsequent changes touched the same code:
```bash
# Start revert
git revert <commit-hash>
# If conflicts occur:
# Conflict in calculator.py
# CONFLICT (content): Merge conflict in calculator.py
```
**To resolve:**
1. Open conflicted files and fix conflicts (look for `<<<<<<<` markers)
2. Stage resolved files:
```bash
git add <resolved-files>
```
3. Continue the revert:
```bash
git revert --continue
```
Or abort if you change your mind:
```bash
git revert --abort
```
## Common Mistakes
### 1. Forgetting -m for Merge Commits
```bash
# ❌ Wrong - will fail
git revert <merge-commit>
# ✅ Correct
git revert -m 1 <merge-commit>
```
### 2. Trying to Re-Merge After Revert
```bash
# After reverting a merge:
git revert -m 1 <merge-commit>
# ❌ This won't work as expected
git merge feature-branch # Empty merge!
# ✅ Do this instead
git revert <the-revert-commit> # Revert the revert
```
### 3. Using Reset on Pushed Commits
```bash
# ❌ NEVER do this with pushed commits
git reset --hard HEAD~3
# ✅ Do this instead
git revert HEAD~3..HEAD
```
### 4. Reverting Commits in Wrong Order
When reverting multiple related commits, revert from newest to oldest:
```bash
# If you have: A → B → C (and C depends on B)
# ✅ Correct order
git revert C
git revert B
# ❌ Wrong order (may cause conflicts)
git revert B # Conflict! C still references B
git revert C
```
## Best Practices
1. **Write clear revert messages:**
```bash
git revert <hash> -m "Revert authentication - security issue #1234"
```
2. **Link to issue tracking:**
```
Revert "Add new payment system"
This reverts commit abc123.
Critical bug in payment processing.
See bug tracker: ISSUE-1234
```
3. **Test after reverting:**
- Run your test suite
- Verify the application still works
- Check no unintended changes occurred
4. **Communicate with team:**
- Announce reverts in team chat
- Explain why the revert was necessary
- Provide timeline for re-introducing the feature
5. **Keep reverts focused:**
- Revert the minimum necessary
- Don't bundle multiple unrelated reverts
- One problem = one revert commit
## Troubleshooting
### "Commit is a merge but no -m option was given"
**Problem:** Trying to revert a merge commit without `-m`.
**Solution:**
```bash
git revert -m 1 <merge-commit-hash>
```
### "Empty Revert / No Changes"
**Problem:** Revert doesn't seem to do anything.
**Possible causes:**
- Commit was already reverted
- Subsequent commits already undid the changes
- Wrong commit hash
**Solution:**
```bash
# Check what the commit actually changed
git show <commit-hash>
# Check if already reverted
git log --grep="Revert"
```
### "Conflicts During Revert"
**Problem:** Revert causes merge conflicts.
**Why:** Subsequent commits modified the same code.
**Solution:**
1. Manually resolve conflicts in affected files
2. `git add <resolved-files>`
3. `git revert --continue`
Or consider fixing forward with a new commit instead of reverting.
### "Can't Re-Merge After Reverting Merge"
**Problem:** After reverting a merge, re-merging the branch brings no changes.
**Solution:** Revert the revert commit:
```bash
# Find the revert commit
git log --oneline
# Revert the revert (brings changes back)
git revert <revert-commit-hash>
```
## Advanced: Revert Internals
Understanding what revert does under the hood:
```bash
# Revert creates a new commit with inverse changes
git revert <commit-hash>
# This is equivalent to:
git diff <commit-hash>^..<commit-hash> > changes.patch
patch -R < changes.patch # Apply in reverse
git add .
git commit -m "Revert '<original message>'"
```
**Key insight:** Revert computes the diff of the target commit, inverts it, and applies it as a new commit.
## Going Further
Now that you understand revert, you're ready for:
- **Module 06: Git Reset** - Learn the dangerous but powerful local history rewriting
- **Module 07: Git Stash** - Temporarily set aside uncommitted changes
- **Module 08: Multiplayer Git** - Collaborate with advanced workflows
## Summary
You've learned:
- ✅ `git revert` creates new commits that undo previous changes
- ✅ Revert is safe for shared/pushed commits
- ✅ Merge commits require `-m 1` or `-m 2` flag
- ✅ Parent 1 = branch merged into, Parent 2 = branch merged from
- ✅ Can't simply re-merge after reverting a merge
- ✅ Multiple commits can be reverted in one command
- ✅ Revert preserves complete history for audit trails
**The Golden Rule of Revert:** Use revert for any commit that might be shared with others.
## Next Steps
1. Complete all three challenge scenarios
2. Run `./verify.ps1` to check your solutions
3. Experiment with reverting different commits
4. Move on to Module 06: Git Reset (dangerous but powerful!)
---
**Need Help?**
- Review the command reference above
- Check the troubleshooting section
- Re-run `./setup.ps1` to start fresh
- Practice reverting in different orders to understand the behavior

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#!/usr/bin/env pwsh
<#
.SYNOPSIS
Resets the Module 05 challenge environment to start fresh.
.DESCRIPTION
This script removes the challenge directory and re-runs setup.ps1
to create a fresh challenge environment.
#>
Write-Host "`n=== Resetting Module 05: Git Revert Challenge ===" -ForegroundColor Cyan
# Check if challenge directory exists
if (Test-Path "challenge") {
Write-Host "Removing existing challenge directory..." -ForegroundColor Yellow
Remove-Item -Recurse -Force "challenge"
Write-Host "[OK] Challenge directory removed" -ForegroundColor Green
} else {
Write-Host "[INFO] No existing challenge directory found" -ForegroundColor Yellow
}
# Run setup to create fresh environment
Write-Host "`nRunning setup to create fresh challenge environment..." -ForegroundColor Cyan
& "$PSScriptRoot/setup.ps1"

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#!/usr/bin/env pwsh
<#
.SYNOPSIS
Sets up the Module 05 challenge environment for learning git revert.
.DESCRIPTION
This script creates a challenge directory with three branches demonstrating
different revert scenarios:
- regular-revert: Basic revert of a single bad commit
- merge-revert: Reverting a merge commit with -m flag
- multi-revert: Reverting multiple commits at once
#>
Write-Host "`n=== Setting up Module 05: Git Revert 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: Regular Revert (Basic)
# ============================================================================
Write-Host "`nScenario 1: Creating regular-revert branch..." -ForegroundColor Cyan
# Initial commit
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Initial calculator implementation" | Out-Null
# Create regular-revert branch
git switch -c regular-revert | Out-Null
# Good commit: Add multiply
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def multiply(a, b):
"""Multiply two numbers."""
return a * b
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add multiply function" | Out-Null
# BAD commit: Add broken divide function
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def multiply(a, b):
"""Multiply two numbers."""
return a * b
def divide(a, b):
"""Divide a by b - BROKEN: doesn't handle division by zero!"""
return a / b # This will crash if b is 0!
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add broken divide function - needs to be reverted!" | Out-Null
# Good commit: Add modulo (after bad commit)
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def multiply(a, b):
"""Multiply two numbers."""
return a * b
def divide(a, b):
"""Divide a by b - BROKEN: doesn't handle division by zero!"""
return a / b # This will crash if b is 0!
def modulo(a, b):
"""Return remainder of a divided by b."""
return a % b
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add modulo function" | Out-Null
Write-Host "[CREATED] regular-revert branch with bad divide commit" -ForegroundColor Green
# ============================================================================
# SCENARIO 2: Merge Revert (Merge Commit with -m flag)
# ============================================================================
Write-Host "`nScenario 2: Creating merge-revert scenario..." -ForegroundColor Cyan
# Switch back to main
git switch main | Out-Null
# Create merge-revert branch
git switch -c merge-revert | Out-Null
# Create a feature branch to merge
git switch -c feature-auth | Out-Null
# Add auth functionality
$authContent = @"
# auth.py - Authentication module
def login(username, password):
\"\"\"Login user.\"\"\"
print(f"Logging in {username}...")
return True
def logout(username):
\"\"\"Logout user.\"\"\"
print(f"Logging out {username}...")
return True
"@
Set-Content -Path "auth.py" -Value $authContent
git add .
git commit -m "Add authentication module" | Out-Null
# Add password validation
$authContent = @"
# auth.py - Authentication module
def validate_password(password):
\"\"\"Validate password strength.\"\"\"
return len(password) >= 8
def login(username, password):
\"\"\"Login user.\"\"\"
if not validate_password(password):
print("Password too weak!")
return False
print(f"Logging in {username}...")
return True
def logout(username):
\"\"\"Logout user.\"\"\"
print(f"Logging out {username}...")
return True
"@
Set-Content -Path "auth.py" -Value $authContent
git add .
git commit -m "Add password validation" | Out-Null
# Integrate auth into calculator (part of the feature branch)
$calcContent = @"
# calculator.py - Simple calculator
from auth import login
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def secure_divide(a, b, username):
"""Secure divide - requires authentication."""
if login(username, "password123"):
return a / b
return None
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Integrate auth into calculator" | Out-Null
# Switch back to merge-revert and merge feature-auth
git switch merge-revert | Out-Null
git merge feature-auth --no-ff -m "Merge feature-auth branch" | Out-Null
Write-Host "[CREATED] merge-revert branch with merge commit to revert" -ForegroundColor Green
# ============================================================================
# SCENARIO 3: Multi Revert (Multiple Bad Commits)
# ============================================================================
Write-Host "`nScenario 3: Creating multi-revert branch..." -ForegroundColor Cyan
# Switch back to main
git switch main | Out-Null
# Create multi-revert branch
git switch -c multi-revert | Out-Null
# Reset calculator to simple version
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Reset to basic calculator" | Out-Null
# Good commit: Add power function
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def power(a, b):
"""Raise a to the power of b."""
return a ** b
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add power function" | Out-Null
# BAD commit 1: Add broken square_root
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def power(a, b):
"""Raise a to the power of b."""
return a ** b
def square_root(a):
"""BROKEN: Returns wrong result for negative numbers!"""
return a ** 0.5 # This returns NaN for negative numbers!
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add broken square_root - REVERT THIS!" | Out-Null
# BAD commit 2: Add broken logarithm
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def power(a, b):
"""Raise a to the power of b."""
return a ** b
def square_root(a):
"""BROKEN: Returns wrong result for negative numbers!"""
return a ** 0.5 # This returns NaN for negative numbers!
def logarithm(a):
"""BROKEN: Doesn't handle zero or negative numbers!"""
import math
return math.log(a) # This crashes for a <= 0!
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add broken logarithm - REVERT THIS TOO!" | Out-Null
# Good commit: Add absolute value (after bad commits)
$calcContent = @"
# calculator.py - Simple calculator
def add(a, b):
"""Add two numbers."""
return a + b
def subtract(a, b):
"""Subtract b from a."""
return a - b
def power(a, b):
"""Raise a to the power of b."""
return a ** b
def square_root(a):
"""BROKEN: Returns wrong result for negative numbers!"""
return a ** 0.5 # This returns NaN for negative numbers!
def logarithm(a):
"""BROKEN: Doesn't handle zero or negative numbers!"""
import math
return math.log(a) # This crashes for a <= 0!
def absolute(a):
"""Return absolute value of a."""
return abs(a)
"@
Set-Content -Path "calculator.py" -Value $calcContent
git add .
git commit -m "Add absolute value function" | Out-Null
Write-Host "[CREATED] multi-revert branch with two bad commits to revert" -ForegroundColor Green
# ============================================================================
# Return to regular-revert to start
# ============================================================================
git switch regular-revert | Out-Null
# Return to module directory
Set-Location ..
Write-Host "`n=== Setup Complete! ===" -ForegroundColor Green
Write-Host "`nThree revert scenarios have been created:" -ForegroundColor Cyan
Write-Host " 1. regular-revert - Revert a single bad commit (basic)" -ForegroundColor White
Write-Host " 2. merge-revert - Revert a merge commit with -m flag" -ForegroundColor White
Write-Host " 3. multi-revert - Revert multiple bad commits" -ForegroundColor White
Write-Host "`nYou are currently on the 'regular-revert' branch." -ForegroundColor Cyan
Write-Host "`nNext steps:" -ForegroundColor Cyan
Write-Host " 1. cd challenge" -ForegroundColor White
Write-Host " 2. Read the README.md for detailed instructions" -ForegroundColor White
Write-Host " 3. Complete each revert challenge" -ForegroundColor White
Write-Host " 4. Run '..\verify.ps1' to check your solutions" -ForegroundColor White
Write-Host ""

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#!/usr/bin/env pwsh
<#
.SYNOPSIS
Verifies the Module 05 challenge solutions.
.DESCRIPTION
Checks that all three revert scenarios have been completed correctly:
- regular-revert: Single commit reverted
- merge-revert: Merge commit reverted with -m flag
- multi-revert: Multiple commits reverted
#>
Write-Host "`n=== Verifying Module 05: Git Revert Solutions ===" -ForegroundColor Cyan
$allChecksPassed = $true
$originalDir = Get-Location
# Check if challenge directory exists
if (-not (Test-Path "challenge")) {
Write-Host "[FAIL] Challenge directory not found. Run setup.ps1 first." -ForegroundColor Red
exit 1
}
Set-Location "challenge"
# Check if git repository exists
if (-not (Test-Path ".git")) {
Write-Host "[FAIL] Not a git repository. Run setup.ps1 first." -ForegroundColor Red
Set-Location $originalDir
exit 1
}
# ============================================================================
# SCENARIO 1: Regular Revert Verification
# ============================================================================
Write-Host "`n=== Scenario 1: Regular Revert ===" -ForegroundColor Cyan
git switch regular-revert 2>&1 | Out-Null
if ($LASTEXITCODE -ne 0) {
Write-Host "[FAIL] regular-revert branch not found" -ForegroundColor Red
$allChecksPassed = $false
} else {
# Check that a revert commit exists
$revertCommit = git log --oneline --grep="Revert" 2>$null
if ($revertCommit) {
Write-Host "[PASS] Revert commit found" -ForegroundColor Green
} else {
Write-Host "[FAIL] No revert commit found" -ForegroundColor Red
Write-Host "[HINT] Use: git revert <commit-hash>" -ForegroundColor Yellow
$allChecksPassed = $false
}
# Check that calculator.py exists
if (Test-Path "calculator.py") {
$calcContent = Get-Content "calculator.py" -Raw
# Check that divide function is NOT in the code (was reverted)
if ($calcContent -notmatch "def divide") {
Write-Host "[PASS] Broken divide function successfully reverted" -ForegroundColor Green
} else {
Write-Host "[FAIL] divide function still exists (should be reverted)" -ForegroundColor Red
Write-Host "[HINT] The bad commit should be reverted, removing the divide function" -ForegroundColor Yellow
$allChecksPassed = $false
}
# Check that modulo function still exists (should be preserved)
if ($calcContent -match "def modulo") {
Write-Host "[PASS] modulo function preserved (good commit after bad one)" -ForegroundColor Green
} else {
Write-Host "[FAIL] modulo function missing (should still exist)" -ForegroundColor Red
Write-Host "[HINT] Only revert the bad commit, not the good ones after it" -ForegroundColor Yellow
$allChecksPassed = $false
}
# Check that multiply function exists (should be preserved)
if ($calcContent -match "def multiply") {
Write-Host "[PASS] multiply function preserved (good commit before bad one)" -ForegroundColor Green
} else {
Write-Host "[FAIL] multiply function missing" -ForegroundColor Red
$allChecksPassed = $false
}
} else {
Write-Host "[FAIL] calculator.py not found" -ForegroundColor Red
$allChecksPassed = $false
}
}
# ============================================================================
# SCENARIO 2: Merge Revert Verification
# ============================================================================
Write-Host "`n=== Scenario 2: Merge Revert ===" -ForegroundColor Cyan
git switch merge-revert 2>&1 | Out-Null
if ($LASTEXITCODE -ne 0) {
Write-Host "[FAIL] merge-revert branch not found" -ForegroundColor Red
$allChecksPassed = $false
} else {
# Check that a revert commit for the merge exists
$revertMerge = git log --oneline --grep="Revert.*Merge" 2>$null
if ($revertMerge) {
Write-Host "[PASS] Merge revert commit found" -ForegroundColor Green
} else {
Write-Host "[FAIL] No merge revert commit found" -ForegroundColor Red
Write-Host "[HINT] Use: git revert -m 1 <merge-commit-hash>" -ForegroundColor Yellow
$allChecksPassed = $false
}
# Check that the original merge commit still exists (revert doesn't erase it)
$mergeCommit = git log --merges --oneline --grep="Merge feature-auth" 2>$null
if ($mergeCommit) {
Write-Host "[PASS] Original merge commit still in history (not erased)" -ForegroundColor Green
} else {
Write-Host "[INFO] Original merge commit not found (this is OK if you used a different approach)" -ForegroundColor Yellow
}
# Check that auth.py no longer exists or its effects are reverted
if (-not (Test-Path "auth.py")) {
Write-Host "[PASS] auth.py removed (merge reverted successfully)" -ForegroundColor Green
} else {
Write-Host "[INFO] auth.py still exists (check if merge was fully reverted)" -ForegroundColor Yellow
}
# Check that calculator.py exists
if (Test-Path "calculator.py") {
$calcContent = Get-Content "calculator.py" -Raw
# After reverting the merge, calculator shouldn't import auth
if ($calcContent -notmatch "from auth import") {
Write-Host "[PASS] Auth integration reverted from calculator.py" -ForegroundColor Green
} else {
Write-Host "[FAIL] calculator.py still imports auth (merge not fully reverted)" -ForegroundColor Red
Write-Host "[HINT] Reverting the merge should remove the auth integration" -ForegroundColor Yellow
$allChecksPassed = $false
}
}
}
# ============================================================================
# SCENARIO 3: Multi Revert Verification
# ============================================================================
Write-Host "`n=== Scenario 3: Multi Revert ===" -ForegroundColor Cyan
git switch multi-revert 2>&1 | Out-Null
if ($LASTEXITCODE -ne 0) {
Write-Host "[FAIL] multi-revert branch not found" -ForegroundColor Red
$allChecksPassed = $false
} else {
# Count revert commits
$revertCommits = git log --oneline --grep="Revert" 2>$null
$revertCount = ($revertCommits | Measure-Object).Count
if ($revertCount -ge 2) {
Write-Host "[PASS] Found $revertCount revert commits (expected at least 2)" -ForegroundColor Green
} else {
Write-Host "[FAIL] Found only $revertCount revert commit(s), need at least 2" -ForegroundColor Red
Write-Host "[HINT] Revert both bad commits: git revert <commit1> <commit2>" -ForegroundColor Yellow
$allChecksPassed = $false
}
# Check calculator.py content
if (Test-Path "calculator.py") {
$calcContent = Get-Content "calculator.py" -Raw
# Check that square_root is NOT in code (reverted)
if ($calcContent -notmatch "def square_root") {
Write-Host "[PASS] Broken square_root function reverted" -ForegroundColor Green
} else {
Write-Host "[FAIL] square_root function still exists (should be reverted)" -ForegroundColor Red
$allChecksPassed = $false
}
# Check that logarithm is NOT in code (reverted)
if ($calcContent -notmatch "def logarithm") {
Write-Host "[PASS] Broken logarithm function reverted" -ForegroundColor Green
} else {
Write-Host "[FAIL] logarithm function still exists (should be reverted)" -ForegroundColor Red
$allChecksPassed = $false
}
# Check that power function still exists (good commit before bad ones)
if ($calcContent -match "def power") {
Write-Host "[PASS] power function preserved" -ForegroundColor Green
} else {
Write-Host "[FAIL] power function missing (should still exist)" -ForegroundColor Red
$allChecksPassed = $false
}
# Check that absolute function still exists (good commit after bad ones)
if ($calcContent -match "def absolute") {
Write-Host "[PASS] absolute function preserved" -ForegroundColor Green
} else {
Write-Host "[FAIL] absolute function missing (should still exist)" -ForegroundColor Red
$allChecksPassed = $false
}
} else {
Write-Host "[FAIL] calculator.py not found" -ForegroundColor Red
$allChecksPassed = $false
}
}
Set-Location $originalDir
# Final summary
Write-Host ""
if ($allChecksPassed) {
Write-Host "=========================================" -ForegroundColor Green
Write-Host " CONGRATULATIONS! ALL SCENARIOS PASSED!" -ForegroundColor Green
Write-Host "=========================================" -ForegroundColor Green
Write-Host "`nYou've mastered git revert!" -ForegroundColor Cyan
Write-Host "You now understand:" -ForegroundColor Cyan
Write-Host " ✓ Reverting regular commits safely" -ForegroundColor White
Write-Host " ✓ Reverting merge commits with -m flag" -ForegroundColor White
Write-Host " ✓ Reverting multiple commits at once" -ForegroundColor White
Write-Host " ✓ Preserving history while undoing changes" -ForegroundColor White
Write-Host "`nReady for Module 06: Git Reset!" -ForegroundColor Green
Write-Host ""
exit 0
} else {
Write-Host "[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 ""
exit 1
}