为何无法查看Python中__builtins__模块的源代码？

Hey there! Let's unpack why you're hitting that error when running inspect.getsource(__builtins__). Here's what's going on:

1. __builtins__ isn't a proper module object #

First off, __builtins__ is a special, context-dependent name in Python:

• In the main interpreter scope, it's usually a reference to the actual built-in module (__builtin__ in Python 2, builtins in Python 3).
• In other modules, it's often just the dictionary of the built-in module (not the module itself).

Since inspect.getsource() expects an object tied to Python source code (like a function, class, or proper module), passing a dictionary or this indirect reference will fail—hence the traceback where inspect can't locate a valid source file for the object.

2. Most built-in functionality is written in C #

Even if you target the real built-in module (e.g., import __builtin__ in Python 2), core functions and objects like print(), len(), or int are implemented in C, not Python. inspect.getsource() can only retrieve code for objects defined in .py files—there's no Python source to fetch for these C-backed built-ins.

How to Work Around This #

• Access the actual built-in module first:
  For Python 2:

  import __builtin__
  import inspect
  # Try fetching source for Python-defined parts of the module (if any exist)
  inspect.getsource(__builtin__)  # May still fail for the module itself, but try specific items
  

  For Python 3:

  import builtins
  import inspect
  inspect.getsource(builtins)
  

• Check Python-implemented helpers: A small number of utility functions in the built-in module might be written in Python—you can try inspect.getsource() on those specific items if you find them.
• View the C source code: If you want to dig into how core built-ins work, you'll need to look at Python's official C source files (found in the Objects/ and Python/ directories of the Python repository).

Your Error Breakdown #

The traceback you shared fails at getfile(object) because __builtins__ (in your context) isn't linked to a valid .py source file. Either it's a dictionary, or the underlying module's core logic is implemented in C with no associated Python source.

内容的提问来源于stack exchange，提问作者Billal BEGUERADJ