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compile(optimize=2) doesn't del docstrings/asserts, ignores -OO & PYTHONOPTIMIZE=2 #112909
Closed as not planned
Description
Bug report
Bug description:
import ast
py_test_source = '''
def test() :
"""docstring"""
assert True
...
'''
ast_obj = compile( # https://docs.python.org/library/functions.html#compile
source = py_test_source ,
filename = "" ,
mode = "exec" ,
flags = ast.PyCF_ONLY_AST ,
dont_inherit = 1 ,
optimize = 2 ,
)
print( ast.unparse( ast_obj ) )as i understand the compile() documentation ,
the above example should remove the docstring ,
and the assert line , but it doesn't .
setting the env var PYTHONOPTIMIZE=2 and then
running python with the cmdLine option -OO
this time with
a) compile( ... , dont_inherit=False , ... ) without optimize
b) compile( ... , dont_inherit=0 , ... ) without optimize
c) compile( ... ) without : dont_inherit , optimize
didn't chage the outcome :
compile() never removes docstrings/asserts .
looks like compile() ignores its arg optimize=2
and -OO and PYTHONOPTIMIZE=2 .
CPython versions tested on:
3.11.5
Operating systems tested on:
Windows 10 (22H2) 64bit
Activity
terryjreedy commented on Dec 10, 2023
The doc says "The argument optimize specifies the optimization level of the compiler;". With the PyCF_ONLY_AST, you are only running the parser, not the compiler itself. If the parser stripped docstrings and assert statements, then unparse would not work right. Also, def f(): "docstring"` would not compile as the docstring is, here, the required non-empty suite.
If you compile to a code object and exec the code object, the resulting test function object will not have a docstring or assert.
Perhaps the doc could be clearer to Python learners, but I am not sure how.
dreamflow commented on Dec 10, 2023
thank you terryjreedy for the detailed explanation 🙂
carljm commented on Dec 17, 2023
This is a duplicate of #108113. In #108154 @iritkatriel added PyCF_OPTIMIZED_AST to solve this (but for Python 3.13+ only.)