Source code for depdigest.core.decorator

import inspect
from functools import wraps
from typing import Any, Callable, Dict, Optional
from .checker import check_dependency
from .config import resolve_config
from smonitor import signal



def dep_digest(library: str, when: Optional[Dict[str, Any]] = None):
    """
    Decorator to declare and enforce a dependency.
    Resolved dynamically at runtime to support configuration changes.
    """
    def decorator(func: Callable):
        # 1. Metadata Registration (Still at definition time)
        if not hasattr(func, '_dependencies'):
            func._dependencies = []
        func._dependencies.append({'library': library, 'when': when})

        # Pre-compute signature
        sig = inspect.signature(func)
        module_path = func.__module__

        @wraps(func)
        @signal(tags=["dependency"], exception_level="DEBUG")
        def wrapper(*args, **kwargs):
            # 2. RESOLVE CONFIG AT RUNTIME
            # This allows tests to register config AFTER function definition
            cfg = resolve_config(module_path)
            
            should_check = True
            if when is not None:
                bound = sig.bind(*args, **kwargs)
                bound.apply_defaults()
                args_dict = bound.arguments
                for k, v in when.items():
                    if k not in args_dict or args_dict[k] != v:
                        should_check = False
                        break
            
            if should_check:
                lib_info = cfg.libraries.get(library, {})
                pypi_name = lib_info.get('pypi')
                check_dependency(library, pypi_name=pypi_name, caller=func.__name__, 
                                 exception_class=cfg.exception_class)
                
            return func(*args, **kwargs)
        
        return wrapper
    return decorator