Too many `elif`s cause `MemoryError` or `RecursionError` #105771

pbzweihander · 2023-06-14T05:09:34Z

Bug report

Save the above code as main.py:

code = """a = 1
if a == 0:
    print(0)
"""
for i in range(1, 10000):
    code += f"""elif a == {i}:
    print({i})
"""

print(code)

... and run python main.py | python causes:

$ python main.py | python
MemoryError
Traceback (most recent call last):
  File "{redacted}/main.py", line 10, in <module>
    print(code)
BrokenPipeError: [Errno 32] Broken pipe

(BrokenPipeError is not relevant here)

Or, run the following code:

code = """a = 1
if a == 0:
    print(0)
"""
for i in range(1, 10000):
    code += f"""elif a == {i}:
    print({i})
"""

exec(code)

... causes the following error:

Traceback (most recent call last):
  File "/home/pbzweihander/projects/python/playground/main.py", line 10, in <module>
    exec(code)
MemoryError

In Python 3.8.10, the error message is changed as follows:

Traceback (most recent call last):
  File "main.py", line 10, in <module>
    exec(code)
RecursionError: maximum recursion depth exceeded during compilation

I think this is a bug, and the bug is due to parsing the Python code to AST causing RecursionError.

Your environment

CPython versions tested on: Python 3.11.3
Operating system and architecture: Arch Linux 6.3.5-arch1-1

The text was updated successfully, but these errors were encountered:

pbzweihander added the type-bug An unexpected behavior, bug, or error label Jun 14, 2023

Too many elifs cause MemoryError or RecursionError #105771

Too many elifs cause MemoryError or RecursionError #105771

Comments

pbzweihander commented Jun 14, 2023

Bug report

Your environment

Too many `elif`s cause `MemoryError` or `RecursionError` #105771

Too many `elif`s cause `MemoryError` or `RecursionError` #105771