git / moonbite-core / test/lint/lint-python-mutable-default-parameters.sh · raw

#!/usr/bin/env bash## Copyright (c) 2019 The Bitcoin Core developers# Distributed under the MIT software license, see the accompanying# file COPYING or http://www.opensource.org/licenses/mit-license.php.## Detect when a mutable list or dict is used as a default parameter value in a Python function.export LC_ALL=CEXIT_CODE=0OUTPUT=$(git grep -E '^\s*def [a-zA-Z0-9_]+\(.*=\s*(\[|\{)' -- "*.py")if [[ ${OUTPUT} != "" ]]; then    echo "A mutable list or dict seems to be used as default parameter value:"    echo    echo "${OUTPUT}"    echo    cat << EXAMPLEThis is how mutable list and dict default parameter values behave:>>> def f(i, j=[], k={}):...     j.append(i)...     k[i] = True...     return j, k...>>> f(1)([1], {1: True})>>> f(1)([1, 1], {1: True})>>> f(2)([1, 1, 2], {1: True, 2: True})The intended behaviour was likely:>>> def f(i, j=None, k=None):...     if j is None:...         j = []...     if k is None:...         k = {}...     j.append(i)...     k[i] = True...     return j, k...>>> f(1)([1], {1: True})>>> f(1)([1], {1: True})>>> f(2)([2], {2: True})EXAMPLE    EXIT_CODE=1fiexit ${EXIT_CODE}