Merge bitcoin/bitcoin#24840: test: port 'lint-shell.sh' to python

bd6ceb4049602aa556a93a0ac8954802dc0bf456 test: port 'lint-shell.sh' to python (whiteh0rse)

Pull request description:

  Converts `test/lint/lint-shell.sh` to Python and updates the docs accordingly. In order for the linter to run, it requires `git` and the `shellcheck` linter to be installed on the system. The script will fail gracefully with a help message if `shellcheck` is not installed.

Top commit has no ACKs.

Tree-SHA512: edc3f1af582b736a0b46f32bd7448e859201dc43f5dd086f16aab49037a1ab936f5376c29fc1006a932b9e98b4f2423d83d98e9666304781a06eb4d2a16f54e3

3 files changed, 94 insertions, 34 deletions

diff --git a/test/README.md b/test/README.md
index d69e515acf..b2fdde96e4 100644
--- a/test/README.md
+++ b/test/README.md
@@ -309,7 +309,7 @@ Use the `-v` option for verbose output.
 | [`lint-python.py`](lint/lint-python.py) | [mypy](https://github.com/python/mypy)
 | [`lint-python.py`](lint/lint-python.py) | [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-shell.py`](lint/lint-shell.py) | [ShellCheck](https://github.com/koalaman/shellcheck)
 | [`lint-spelling.py`](lint/lint-spelling.py) | [codespell](https://github.com/codespell-project/codespell)
 
 In use versions and install instructions are available in the [CI setup](../ci/lint/04_install.sh).
diff --git a/test/lint/lint-shell.py b/test/lint/lint-shell.py
new file mode 100755
index 0000000000..f1e4494350
--- /dev/null
+++ b/test/lint/lint-shell.py
@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2018-2022 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+"""
+Check for shellcheck warnings in shell scripts.
+"""
+
+import subprocess
+import re
+import sys
+
+# Disabled warnings:
+DISABLED = [
+    'SC2162', # read without -r will mangle backslashes.
+]
+
+def check_shellcheck_install():
+    try:
+        subprocess.run(['shellcheck', '--version'], stdout=subprocess.DEVNULL, check=True)
+    except FileNotFoundError:
+        print('Skipping shell linting since shellcheck is not installed.')
+        sys.exit(0)
+
+def get_files(command):
+    output = subprocess.run(command, stdout=subprocess.PIPE, universal_newlines=True)
+    files = output.stdout.split('\n')
+
+    # remove whitespace element
+    files = list(filter(None, files))
+    return files
+
+def main():
+    check_shellcheck_install()
+
+    # build the `exclude` flag
+    exclude = '--exclude=' + ','.join(DISABLED)
+
+    # build the `sourced files` list
+    sourced_files_cmd = [
+        'git',
+        'grep',
+        '-El',
+        r'^# shellcheck shell=',
+    ]
+    sourced_files = get_files(sourced_files_cmd)
+
+    # build the `guix files` list
+    guix_files_cmd = [
+        'git',
+        'grep',
+        '-El',
+        r'^#!\/usr\/bin\/env bash',
+        '--',
+        'contrib/guix',
+        'contrib/shell',
+    ]
+    guix_files = get_files(guix_files_cmd)
+
+    # build the other script files list
+    files_cmd = [
+        'git',
+        'ls-files',
+        '--',
+        '*.sh',
+    ]
+    files = get_files(files_cmd)
+    # remove everything that doesn't match this regex
+    reg = re.compile(r'src/[leveldb,secp256k1,minisketch,univalue]')
+    files[:] = [file for file in files if not reg.match(file)]
+
+    # build the `shellcheck` command
+    shellcheck_cmd = [
+        'shellcheck',
+        '--external-sources',
+        '--check-sourced',
+        '--source-path=SCRIPTDIR',
+    ]
+    shellcheck_cmd.append(exclude)
+    shellcheck_cmd.extend(sourced_files)
+    shellcheck_cmd.extend(guix_files)
+    shellcheck_cmd.extend(files)
+
+    # run the `shellcheck` command
+    try:
+        subprocess.check_call(shellcheck_cmd)
+    except subprocess.CalledProcessError:
+        sys.exit(1)
+
+if __name__ == '__main__':
+    main()
diff --git a/test/lint/lint-shell.sh b/test/lint/lint-shell.sh
deleted file mode 100755
index 5fa104fce6..0000000000
--- a/test/lint/lint-shell.sh
+++ /dev/null
@@ -1,33 +0,0 @@
-#!/usr/bin/env bash
-#
-# Copyright (c) 2018-2021 The Bitcoin Core developers
-# Distributed under the MIT software license, see the accompanying
-# file COPYING or http://www.opensource.org/licenses/mit-license.php.
-#
-# Check for shellcheck warnings in shell scripts.
-
-export LC_ALL=C
-
-# Disabled warnings:
-disabled=(
-    SC2162 # read without -r will mangle backslashes.
-)
-
-EXIT_CODE=0
-
-if ! command -v shellcheck > /dev/null; then
-    echo "Skipping shell linting since shellcheck is not installed."
-    exit $EXIT_CODE
-fi
-
-SHELLCHECK_CMD=(shellcheck --external-sources --check-sourced --source-path=SCRIPTDIR)
-EXCLUDE="--exclude=$(IFS=','; echo "${disabled[*]}")"
-# Check shellcheck directive used for sourced files
-mapfile -t SOURCED_FILES < <(git ls-files | xargs gawk '/^# shellcheck shell=/ {print FILENAME} {nextfile}')
-mapfile -t GUIX_FILES < <(git ls-files contrib/guix contrib/shell | xargs gawk '/^#!\/usr\/bin\/env bash/ {print FILENAME} {nextfile}')
-mapfile -t FILES < <(git ls-files -- '*.sh' | grep -vE 'src/(leveldb|secp256k1|minisketch|univalue)/')
-if ! "${SHELLCHECK_CMD[@]}" "$EXCLUDE" "${SOURCED_FILES[@]}" "${GUIX_FILES[@]}" "${FILES[@]}"; then
-    EXIT_CODE=1
-fi
-
-exit $EXIT_CODE