Update inspect to better match how we represent builtin functions

from_cpython/Lib/inspect.py

@@ -818,6 +818,11 @@ def getargspec(func):
         func = func.im_func
     if not isfunction(func):
         raise TypeError('{!r} is not a Python function'.format(func))
+    # Pyston change: many of our builtin functions are of type FunctionType, but
+    # don't have full introspection available.  I think this check catches most of them,
+    # though I think it allows some cases that CPython does not:
+    if func.func_code.co_argcount > len(func.func_code.co_varnames):
+        raise TypeError('{!r} is not a Python function'.format(func))
     args, varargs, varkw = getargs(func.func_code)
     return ArgSpec(args, varargs, varkw, func.func_defaults)
 

test/tests/inspect_test.py

@@ -5,8 +5,21 @@ def f1(a, b=2, *args, **kw):
 def f2():
     pass
 
+class C(object):
+    def __init__(self):
+        pass
+
+class D(object):
+    pass
+
 print inspect.getargspec(f1)
 print inspect.getargspec(f2)
+print inspect.getargspec(C.__init__)
+print inspect.getargspec(C().__init__)
+try:
+    print inspect.getargspec(D.__init__)
+except Exception as e:
+    print type(e)
 
 def G():
     yield 1