#!/usr/bin/env python3
"""
Demonstration of dry-run functionality for Fast Apply MCP server.
"""
import os
import sys
import tempfile
# Add current directory to Python path
sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
from fastapply.main import WORKSPACE_ROOT, fast_apply_connector
def test_dry_run_functionality():
"""Test the dry-run functionality with a sample file."""
# Create a temporary test file
test_content = '''#!/usr/bin/env python3
"""
Simple test file for dry-run functionality demonstration.
"""
def hello_world():
"""A simple greeting function."""
message = "Hello, World!"
print(message)
return message
def add_numbers(a, b):
"""Add two numbers together."""
result = a + b
return result
if __name__ == "__main__":
# Test the functions
greeting = hello_world()
sum_result = add_numbers(5, 3)
print(f"Greeting: {greeting}")
print(f"Sum: {sum_result}")
'''
with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as f:
f.write(test_content)
test_file_path = f.name
try:
print("🔍 Testing Dry-Run Functionality")
print("=" * 50)
print(f"Test file: {test_file_path}")
print(f"Workspace root: {WORKSPACE_ROOT}")
print()
# Test 1: Simple function modification
print("Test 1: Adding a new function")
code_edit1 = """// ... existing code ...
def multiply_numbers(a, b):
# Multiply two numbers together
result = a * b
return result
// ... existing code ..."""
instruction1 = "Add a new multiply_numbers function after the add_numbers function"
# Simulate dry run
try:
verification_results = fast_apply_connector.apply_edit(
original_code=test_content,
code_edit=code_edit1,
instruction=instruction1,
file_path=test_file_path,
)
print("✅ Dry run completed successfully!")
print(f" • Has changes: {verification_results['has_changes']}")
print(f" • Merged code length: {len(verification_results['merged_code'])} chars")
print(f" • Validation errors: {verification_results['validation']['has_errors']}")
print(f" • Validation warnings: {len(verification_results['validation']['warnings'])}")
if verification_results["has_changes"] and verification_results["udiff"]:
print("\n📋 Unified Diff (first 10 lines):")
diff_lines = verification_results["udiff"].split("\n")[:10]
for line in diff_lines:
print(f" {line}")
if len(verification_results["udiff"].split("\n")) > 10:
print(" ... (truncated)")
except Exception as e:
print(f"❌ Dry run failed: {e}")
print("\n" + "-" * 50 + "\n")
# Test 2: Modifying existing function
print("Test 2: Modifying existing function")
code_edit2 = """// ... existing code ...
def hello_world():
# A simple greeting function
message = "Hello, Dry-Run World!"
print(message)
print("This is a dry-run test!")
return message
// ... existing code ..."""
instruction2 = "Modify the hello_world function to include additional output"
try:
verification_results = fast_apply_connector.apply_edit(
original_code=test_content,
code_edit=code_edit2,
instruction=instruction2,
file_path=test_file_path,
)
print("✅ Dry run completed successfully!")
print(f" • Has changes: {verification_results['has_changes']}")
print(f" • Original size: {len(test_content)} chars")
print(f" • New size: {len(verification_results['merged_code'])} chars")
print(f" • Size change: {len(verification_results['merged_code']) - len(test_content)} chars")
except Exception as e:
print(f"❌ Dry run failed: {e}")
print("\n" + "-" * 50 + "\n")
# Test 3: No changes (identical content)
print("Test 3: Applying identical content (no changes)")
code_edit3 = test_content # Same as original
instruction3 = "Apply identical content (should result in no changes)"
try:
verification_results = fast_apply_connector.apply_edit(
original_code=test_content,
code_edit=code_edit3,
instruction=instruction3,
file_path=test_file_path,
)
print("✅ Dry run completed successfully!")
print(f" • Has changes: {verification_results['has_changes']}")
if not verification_results["has_changes"]:
print(" ✅ Correctly detected no changes needed")
except Exception as e:
print(f"❌ Dry run failed: {e}")
print("\n🛡️ Safety Verification:")
print(" • No files were modified during these tests")
print(" • No backups were created")
print(" • All operations were performed in memory only")
finally:
# Clean up test file
if os.path.exists(test_file_path):
os.unlink(test_file_path)
print(f"\n🧹 Cleaned up test file: {test_file_path}")
if __name__ == "__main__":
test_dry_run_functionality()