Merge bitcoin/bitcoin#24778: lint: Convert Python dead code linter test to Python

076cd6835f lint: Convert Python dead code linter to Python (Fabian Jahr)

Pull request description:

  The new python version should produce the exact same output as the bash version but be easier to maintain.

ACKs for top commit:
  MarcoFalke:
    review ACK 076cd6835f

Tree-SHA512: 6d71a5230d612a981958fb6e178214240b09e842ffe35e207cbbda870ca35476626bf832f55d96f2fc7323a2875935edfee30cacef659a8e6ec4bbb28ff6e36a

test/README.md

@@ -308,6 +308,7 @@ Use the `-v` option for verbose output.
 | [`lint-python.sh`](lint/lint-python.sh) | [flake8](https://gitlab.com/pycqa/flake8)
 | [`lint-python.sh`](lint/lint-python.sh) | [mypy](https://github.com/python/mypy)
 | [`lint-python.sh`](lint/lint-python.sh) | [pyzmq](https://github.com/zeromq/pyzmq)
+| [`lint-python-dead-code.py`](lint/lint-python-dead-code.py) | [vulture](https://github.com/jendrikseipp/vulture)
 | [`lint-shell.sh`](lint/lint-shell.sh) | [ShellCheck](https://github.com/koalaman/shellcheck)
 | [`lint-spelling.sh`](lint/lint-spelling.sh) | [codespell](https://github.com/codespell-project/codespell)
 

test/lint/lint-python-dead-code.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2022 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+"""
+Find dead Python code.
+"""
+
+from subprocess import check_output, STDOUT, CalledProcessError
+
+FILES_ARGS = ['git', 'ls-files', '--', '*.py']
+
+
+def check_vulture_install():
+    try:
+        check_output(["vulture", "--version"])
+    except FileNotFoundError:
+        print("Skipping Python dead code linting since vulture is not installed. Install by running \"pip3 install vulture\"")
+        exit(0)
+
+
+def main():
+    check_vulture_install()
+
+    files = check_output(FILES_ARGS).decode("utf-8").splitlines()
+    # --min-confidence 100 will only report code that is guaranteed to be unused within the analyzed files.
+    # Any value below 100 introduces the risk of false positives, which would create an unacceptable maintenance burden.
+    vulture_args = ['vulture', '--min-confidence=100'] + files
+
+    try:
+        check_output(vulture_args, stderr=STDOUT)
+    except CalledProcessError as e:
+        print(e.output.decode("utf-8"), end="")
+        print("Python dead code detection found some issues")
+        exit(1)
+
+
+if __name__ == "__main__":
+    main()

test/lint/lint-python-dead-code.sh

@@ -1,22 +0,0 @@
-#!/usr/bin/env bash
-#
-# Copyright (c) 2021 The Bitcoin Core developers
-# Distributed under the MIT software license, see the accompanying
-# file COPYING or http://www.opensource.org/licenses/mit-license.php.
-#
-# Find dead Python code.
-
-export LC_ALL=C
-
-if ! command -v vulture > /dev/null; then
-    echo "Skipping Python dead code linting since vulture is not installed. Install by running \"pip3 install vulture\""
-    exit 0
-fi
-
-# --min-confidence 100 will only report code that is guaranteed to be unused within the analyzed files.
-# Any value below 100 introduces the risk of false positives, which would create an unacceptable maintenance burden.
-mapfile -t FILES < <(git ls-files -- "*.py")
-if ! vulture --min-confidence 100 "${FILES[@]}"; then
-    echo "Python dead code detection found some issues"
-    exit 1
-fi