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