git-workshop/module-13-bisect/setup.ps1

#!/usr/bin/env pwsh

<#
.SYNOPSIS
    Sets up the bisect challenge environment.

.DESCRIPTION
    Creates a Git repository with multiple commits where a bug is
    introduced in one of them. Students use bisect to find it.
#>

# Remove existing challenge directory if present
if (Test-Path "challenge") {
    Write-Host "Removing existing challenge directory..." -ForegroundColor Yellow
    Remove-Item -Path "challenge" -Recurse -Force
}

# Create challenge directory
Write-Host "Creating challenge environment..." -ForegroundColor Cyan
New-Item -ItemType Directory -Path "challenge" | Out-Null
Set-Location "challenge"

# Initialize git repository
git init | Out-Null
git config user.name "Workshop User" | Out-Null
git config user.email "user@workshop.local" | Out-Null

# Commit 1: Initial calculator
$calc1 = @"
class Calculator {
  add(a, b) {
    return a + b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc1
git add calculator.js
git commit -m "Initial calculator with add function" | Out-Null

# Commit 2: Add subtract
$calc2 = @"
class Calculator {
  add(a, b) {
    return a + b;
  }

  subtract(a, b) {
    return a - b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc2
git add calculator.js
git commit -m "Add subtract function" | Out-Null

# Commit 3: Add multiply
$calc3 = @"
class Calculator {
  add(a, b) {
    return a + b;
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc3
git add calculator.js
git commit -m "Add multiply function" | Out-Null

# Commit 4: Add divide
$calc4 = @"
class Calculator {
  add(a, b) {
    return a + b;
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc4
git add calculator.js
git commit -m "Add divide function" | Out-Null

# Commit 5: Add modulo
$calc5 = @"
class Calculator {
  add(a, b) {
    return a + b;
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc5
git add calculator.js
git commit -m "Add modulo function" | Out-Null

# Commit 6: BUG - Introduce error in add function
$calc6 = @"
class Calculator {
  add(a, b) {
    return a - b;  // BUG: Should be a + b
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc6
git add calculator.js
git commit -m "Refactor add function for clarity" | Out-Null

# Commit 7: Add power function (bug still exists)
$calc7 = @"
class Calculator {
  add(a, b) {
    return a - b;  // BUG: Should be a + b
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }

  power(a, b) {
    return Math.pow(a, b);
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc7
git add calculator.js
git commit -m "Add power function" | Out-Null

# Commit 8: Add square root
$calc8 = @"
class Calculator {
  add(a, b) {
    return a - b;  // BUG: Should be a + b
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }

  power(a, b) {
    return Math.pow(a, b);
  }

  sqrt(a) {
    return Math.sqrt(a);
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc8
git add calculator.js
git commit -m "Add square root function" | Out-Null

# Commit 9: Add absolute value
$calc9 = @"
class Calculator {
  add(a, b) {
    return a - b;  // BUG: Should be a + b
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }

  power(a, b) {
    return Math.pow(a, b);
  }

  sqrt(a) {
    return Math.sqrt(a);
  }

  abs(a) {
    return Math.abs(a);
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc9
git add calculator.js
git commit -m "Add absolute value function" | Out-Null

# Commit 10: Add max function
$calc10 = @"
class Calculator {
  add(a, b) {
    return a - b;  // BUG: Should be a + b
  }

  subtract(a, b) {
    return a - b;
  }

  multiply(a, b) {
    return a * b;
  }

  divide(a, b) {
    if (b === 0) throw new Error('Division by zero');
    return a / b;
  }

  modulo(a, b) {
    return a % b;
  }

  power(a, b) {
    return Math.pow(a, b);
  }

  sqrt(a) {
    return Math.sqrt(a);
  }

  abs(a) {
    return Math.abs(a);
  }

  max(a, b) {
    return a > b ? a : b;
  }
}

module.exports = Calculator;
"@
Set-Content -Path "calculator.js" -Value $calc10
git add calculator.js
git commit -m "Add max function" | Out-Null

# Create a test file
$test = @"
const Calculator = require('./calculator.js');
const calc = new Calculator();

// Test addition (this will fail due to bug)
const result = calc.add(5, 3);
if (result !== 8) {
  console.log('FAIL: add(5, 3) returned ' + result + ', expected 8');
  process.exit(1);
}

console.log('PASS: All tests passed');
process.exit(0);
"@
Set-Content -Path "test.js" -Value $test

# Return to module directory
Set-Location ..

Write-Host "`n========================================" -ForegroundColor Green
Write-Host "Challenge environment created!" -ForegroundColor Green
Write-Host "========================================" -ForegroundColor Green
Write-Host "`nSituation:" -ForegroundColor Cyan
Write-Host "The calculator has a bug - addition doesn't work correctly!" -ForegroundColor Red
Write-Host "calc.add(5, 3) returns 2 instead of 8" -ForegroundColor Red
Write-Host "`nThe bug was introduced somewhere in the last 10 commits." -ForegroundColor Yellow
Write-Host "Manually checking each commit would be tedious." -ForegroundColor Yellow
Write-Host "Use git bisect to find it efficiently!" -ForegroundColor Green
Write-Host "`nYour task:" -ForegroundColor Yellow
Write-Host "1. Navigate to the challenge directory: cd challenge" -ForegroundColor White
Write-Host "2. Test the bug: node test.js (it will fail)" -ForegroundColor White
Write-Host "3. Start bisect: git bisect start" -ForegroundColor White
Write-Host "4. Mark current as bad: git bisect bad" -ForegroundColor White
Write-Host "5. Mark old commit as good: git bisect good HEAD~10" -ForegroundColor White
Write-Host "6. Git will checkout a commit - test it: node test.js" -ForegroundColor White
Write-Host "7. Mark result: git bisect good (if test passes) or git bisect bad (if it fails)" -ForegroundColor White
Write-Host "8. Repeat until Git finds the first bad commit" -ForegroundColor White
Write-Host "9. Note the commit hash" -ForegroundColor White
Write-Host "10. End bisect: git bisect reset" -ForegroundColor White
Write-Host "11. Create bug-commit.txt with the bad commit hash" -ForegroundColor White
Write-Host "`nHint: The bug is in commit 6 ('Refactor add function for clarity')" -ForegroundColor Cyan
Write-Host "Run '../verify.ps1' from the challenge directory to check your solution.`n" -ForegroundColor Cyan