feat: generate custom coverage config to omit legacy and external compoents (#9221)

* feat: generate custom coverage config to omit legacy and external components

* lint

* fix components config

* also remove deactivated componenets

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

scripts/generate_coverage_config.md

@@ -0,0 +1,36 @@
+# Dynamic Coverage Configuration
+
+This script generates a custom `.coveragerc` file for backend testing that excludes:
+
+1. **Bundled components** - Components listed in `SIDEBAR_BUNDLES` from `src/frontend/src/utils/styleUtils.ts`
+2. **Legacy components** - Python files containing `legacy = True`
+
+## How it works
+
+1. **Reads frontend config**: Parses `styleUtils.ts` to extract bundled component names
+2. **Scans backend files**: Finds all `.py` files in `src/backend/base/langflow/components/` with `legacy = True`
+3. **Generates .coveragerc**: Creates exclusion patterns for pytest-cov
+
+## Usage
+
+### Local development
+```bash
+# Generate config and run tests
+python3 scripts/generate_coverage_config.py
+cd src/backend && python -m pytest --cov=src/backend/base/langflow --cov-config=.coveragerc
+```
+
+### CI Integration
+The script runs automatically in CI before backend tests via `.github/workflows/python_test.yml`.
+
+## Files affected
+
+- **Input**: `src/frontend/src/utils/styleUtils.ts` (SIDEBAR_BUNDLES)
+- **Input**: `src/backend/base/langflow/components/**/*.py` (legacy components)  
+- **Output**: `src/backend/.coveragerc` (auto-generated, in .gitignore)
+
+## Benefits
+
+- **Accurate coverage**: Focuses on actively maintained core code
+- **Dynamic updates**: Automatically adapts when bundles/legacy components change
+- **Codecov compatible**: Generated config works with both local testing and Codecov reporting

scripts/generate_coverage_config.py

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+#!/usr/bin/env python3
+"""Script to generate a custom .coveragerc file for backend testing.
+
+This script:
+1. Reads SIDEBAR_BUNDLES from frontend styleUtils.ts to get bundled component names
+2. Scans backend components for files containing 'legacy = True'
+3. Generates a .coveragerc file that omits these paths from coverage reporting
+
+Usage:
+    python scripts/generate_coverage_config.py
+"""
+
+import re
+from pathlib import Path
+
+
+def extract_sidebar_bundles(frontend_path: Path) -> set[str]:
+    """Extract component names from SIDEBAR_BUNDLES in styleUtils.ts."""
+    style_utils_path = frontend_path / "src/utils/styleUtils.ts"
+
+    if not style_utils_path.exists():
+        print(f"Warning: styleUtils.ts not found at {style_utils_path}")
+        return set()
+
+    bundle_names = set()
+
+    with style_utils_path.open(encoding="utf-8") as f:
+        content = f.read()
+
+    # Find SIDEBAR_BUNDLES array
+    sidebar_match = re.search(r"export const SIDEBAR_BUNDLES = \[(.*?)\];", content, re.DOTALL)
+    if not sidebar_match:
+        print("Warning: SIDEBAR_BUNDLES not found in styleUtils.ts")
+        return set()
+
+    bundles_content = sidebar_match.group(1)
+
+    # Extract name fields using regex
+    name_matches = re.findall(r'name:\s*["\']([^"\']+)["\']', bundles_content)
+
+    for name in name_matches:
+        bundle_names.add(name)
+
+    print(f"Found {len(bundle_names)} bundled components from SIDEBAR_BUNDLES")
+    return bundle_names
+
+
+def find_legacy_components(backend_components_path: Path) -> set[str]:
+    """Find Python files containing 'legacy = True'."""
+    legacy_files = set()
+
+    if not backend_components_path.exists():
+        print(f"Warning: Backend components path not found: {backend_components_path}")
+        return set()
+
+    # Walk through all Python files in components directory
+    for py_file in backend_components_path.rglob("*.py"):
+        try:
+            with py_file.open(encoding="utf-8") as f:
+                content = f.read()
+
+            # Check if file contains 'legacy = True'
+            if re.search(r"\blegacy\s*=\s*True\b", content):
+                # Get relative path from components directory
+                rel_path = py_file.relative_to(backend_components_path)
+                legacy_files.add(str(rel_path))
+
+        except (UnicodeDecodeError, PermissionError) as e:
+            print(f"Warning: Could not read {py_file}: {e}")
+            continue
+
+    print(f"Found {len(legacy_files)} legacy component files")
+    return legacy_files
+
+
+def generate_coveragerc(bundle_names: set[str], legacy_files: set[str], output_path: Path):
+    """Generate .coveragerc file with omit patterns."""
+    # Base coveragerc content
+    config_content = """# Auto-generated .coveragerc file
+# Generated by scripts/generate_coverage_config.py
+# Do not edit manually - changes will be overwritten
+
+[run]
+source = src/backend/base/langflow
+omit =
+    # Test files
+    */tests/*
+    */test_*
+    */*test*
+
+    # Migration files
+    */alembic/*
+    */migrations/*
+
+    # Cache and build files
+    */__pycache__/*
+    */.*
+
+    # Init files (typically just imports)
+    */__init__.py
+
+    # Deactivate Components
+    */components/deactivated/*
+
+"""
+
+    # Add bundled components to omit list
+    if bundle_names:
+        config_content += "    # Bundled components from SIDEBAR_BUNDLES\n"
+        for bundle_name in sorted(bundle_names):
+            config_content += f"    */components/{bundle_name}/*\n"
+        config_content += "\n"
+
+    # Add legacy components to omit list
+    if legacy_files:
+        config_content += "    # Legacy components (contain 'legacy = True')\n"
+        for legacy_file in sorted(legacy_files):
+            # Convert relative path to omit pattern
+            omit_pattern = f"    */components/{legacy_file}\n"
+            config_content += omit_pattern
+
+    config_content += """
+# Note: [report] and [html] sections omitted for Codecov compatibility
+# Codecov handles its own reporting and ignores these sections
+"""
+
+    # Write the config file
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    with output_path.open("w", encoding="utf-8") as f:
+        f.write(config_content)
+
+    print(f"Generated .coveragerc at {output_path}")
+    print(f"  - Omitting {len(bundle_names)} bundled component directories")
+    print(f"  - Omitting {len(legacy_files)} legacy component files")
+
+
+def main():
+    """Main function."""
+    # Determine project root (script is in scripts/ directory)
+    script_dir = Path(__file__).parent
+    project_root = script_dir.parent
+
+    # Paths
+    frontend_path = project_root / "src" / "frontend"
+    backend_components_path = project_root / "src" / "backend" / "base" / "langflow" / "components"
+    output_path = project_root / "src" / "backend" / ".coveragerc"
+
+    print(f"Project root: {project_root}")
+    print(f"Frontend path: {frontend_path}")
+    print(f"Backend components path: {backend_components_path}")
+    print(f"Output path: {output_path}")
+    print()
+
+    # Extract bundled component names
+    bundle_names = extract_sidebar_bundles(frontend_path)
+
+    # Find legacy components
+    legacy_files = find_legacy_components(backend_components_path)
+
+    # Generate .coveragerc file
+    generate_coveragerc(bundle_names, legacy_files, output_path)
+
+    print("\nDone! You can now run backend tests with coverage using:")
+    print("cd src/backend && python -m pytest --cov=src/backend/base/langflow --cov-config=.coveragerc")
+
+
+if __name__ == "__main__":
+    main()