File Content: pkgutil_resolve_name.py """ Resolve a name to an object. It is expected that `name` will be a string in one of the following formats, where W is shorthand for a valid Python identifier and dot stands for a literal period in these pseudo-regexes: W(.W)* W(.W)*:(W(.W)*)? The first form is intended for backward compatibility only. It assumes that some part of the dotted name is a package, and the rest is an object somewhere within that package, possibly nested inside other objects. Because the place where the package stops and the object hierarchy starts can't be inferred by inspection, repeated attempts to import must be done with this form. In the second form, the caller makes the division point clear through the provision of a single colon: the dotted name to the left of the colon is a package to be imported, and the dotted name to the right is the object hierarchy within that package. Only one import is needed in this form. If it ends with the colon, then a module object is returned. The function will return an object (which might be a module), or raise one of the following exceptions: ValueError - if `name` isn't in a recognised format ImportError - if an import failed when it shouldn't have AttributeError - if a failure occurred when traversing the object hierarchy within the imported package to get to the desired object) """ import importlib import re __version__ = "1.3.10" _NAME_PATTERN = None def resolve_name(name): """ Resolve a name to an object. It is expected that `name` will be a string in one of the following formats, where W is shorthand for a valid Python identifier and dot stands for a literal period in these pseudo-regexes: W(.W)* W(.W)*:(W(.W)*)? The first form is intended for backward compatibility only. It assumes that some part of the dotted name is a package, and the rest is an object somewhere within that package, possibly nested inside other objects. Because the place where the package stops and the object hierarchy starts can't be inferred by inspection, repeated attempts to import must be done with this form. In the second form, the caller makes the division point clear through the provision of a single colon: the dotted name to the left of the colon is a package to be imported, and the dotted name to the right is the object hierarchy within that package. Only one import is needed in this form. If it ends with the colon, then a module object is returned. The function will return an object (which might be a module), or raise one of the following exceptions: ValueError - if `name` isn't in a recognised format ImportError - if an import failed when it shouldn't have AttributeError - if a failure occurred when traversing the object hierarchy within the imported package to get to the desired object) """ global _NAME_PATTERN if _NAME_PATTERN is None: # Lazy import to speedup Python startup time import re dotted_words = r'(?!\d)(\w+)(\.(?!\d)(\w+))*' _NAME_PATTERN = re.compile(f'^(?P<pkg>{dotted_words})' f'(?P<cln>:(?P<obj>{dotted_words})?)?$', re.UNICODE) m = _NAME_PATTERN.match(name) if not m: raise ValueError(f'invalid format: {name!r}') gd = m.groupdict() if gd.get('cln'): # there is a colon - a one-step import is all that's needed mod = importlib.import_module(gd['pkg']) parts = gd.get('obj') parts = parts.split('.') if parts else [] else: # no colon - have to iterate to find the package boundary parts = name.split('.') modname = parts.pop(0) # first part *must* be a module/package. mod = importlib.import_module(modname) while parts: p = parts[0] s = f'{modname}.{p}' try: mod = importlib.import_module(s) parts.pop(0) modname = s except ImportError: break # if we reach this point, mod is the module, already imported, and # parts is the list of parts in the object hierarchy to be traversed, or # an empty list if just the module is wanted. result = mod for p in parts: result = getattr(result, p) return result Submit