claude-foundations/formatters/sh

#!/usr/bin/env bash
# Formatter: Shell — shfmt + shellcheck + SETE/LEAK checks
# Contract: $1 = absolute file path, format in place, lint, exit 0 if clean / 1 if errors
#
# SETE-1: shebanged script with no `set -e` / `set -euo pipefail` anywhere
# SETE-2: sh/bash -c string with 2+ ;- or newline-separated commands and no set -e inside
# LEAK-1: command substitution reading a secret-named file interpolated into
#         echo/printf/die/error/fail argument
#
# Missing shfmt AND shellcheck: emit one warning to stderr, still exit 0
# (a missing tool must not block an edit). Any SETE/LEAK finding: print
# "path:line: ID message" to stderr, exit non-zero.

set -uo pipefail

FILE="$1"
[ -z "$FILE" ] && exit 0
[ -f "$FILE" ] || exit 0

HAD_ERRORS=0
HAS_SHFMT=0
HAS_SHELLCHECK=0

# Format with shfmt if available
if command -v shfmt >/dev/null 2>&1; then
	HAS_SHFMT=1
	shfmt -w "$FILE" 2>/dev/null
fi

# Lint with shellcheck if available
if command -v shellcheck >/dev/null 2>&1; then
	HAS_SHELLCHECK=1
	if ! ERRORS=$(shellcheck -f gcc "$FILE" 2>&1); then
		echo "$ERRORS" >&2
		HAD_ERRORS=1
	fi
fi

# --- Custom checks: SETE-1, SETE-2, LEAK-1 ---
# Always run, regardless of shfmt/shellcheck presence. Reads $FILE, emits
# one "path:line: ID message" line per finding to stdout, exits non-zero on
# any finding.

if ! CUSTOM_OUT=$(
	python3 - "$FILE" <<'PYEOF'
import re
import sys

filepath = sys.argv[1]
findings = []

try:
    with open(filepath, 'r', encoding='utf-8', errors='replace') as f:
        content = f.read()
        lines = content.splitlines()
except OSError:
    sys.exit(0)

# SETE-1: shebanged script with no `set -e` / `set -euo pipefail` anywhere
first = lines[0] if lines else ''
if first.startswith('#!'):
    has_sete = False
    for line in lines:
        if re.search(r'(^|[^A-Za-z0-9_])set\s+-[A-Za-z]*[eE]', line):
            has_sete = True
            break
    if not has_sete:
        findings.append((1, "SETE-1 executable shell script without 'set -e'; failed earlier commands will not abort"))

SECRET_RE = re.compile(r'TOKEN|SECRET|KEY|PASSWORD|_JSON_FILE|CREDENTIAL', re.IGNORECASE)
SINK_RE = re.compile(r'\b(echo|printf|die|error|fail)(?=\s|\()')
FILE_READ_RE = re.compile(
    r'(\$\(|`)\s*(cat|<)\s*"\$\{?([A-Za-z_][A-Za-z0-9_]*)\}?"\s*(\)|`)'
)

def count_top_level_commands(s):
    """Count ;- or newline-separated top-level commands in a shell string,
    ignoring separators inside single or double quotes."""
    in_single = False
    in_double = False
    separators = 0
    for c in s:
        if not in_double and c == "'":
            in_single = not in_single
        elif not in_single and c == '"':
            in_double = not in_double
        elif c in ';\n' and not in_single and not in_double:
            separators += 1
    return separators + 1

for i, line in enumerate(lines, 1):
    # LEAK-1: command substitution reading a secret-named file, inside echo/printf/die/error/fail
    sink_match = SINK_RE.search(line)
    if sink_match:
        cmd = sink_match.group(1)
        for cmdsub in FILE_READ_RE.finditer(line):
            var = cmdsub.group(3)
            if SECRET_RE.search(var):
                findings.append((i, "LEAK-1 secret variable '$" + var + "' read into string passed to '" + cmd + "'; could print credential document"))

# SETE-2 runs over the WHOLE source, not line by line: the shape that motivated
# this check spans lines —
#     sh -c "
#         hugo mod get ...
#         hugo mod tidy
#     "
# — so a per-line regex requiring both quotes on one line never matched it.
for m in re.finditer(r'\b(?:sh|bash)\s+-c\s+(["\'])(.*?)\1', content, re.DOTALL):
    body = m.group(2)
    if re.search(r'(^|[^A-Za-z0-9_])set\s+-[A-Za-z]*[eE]', body):
        continue
    n = count_top_level_commands(body)
    if n < 2:
        n = len([ln for ln in body.splitlines() if ln.strip() and not ln.strip().startswith('#')])
    if n >= 2:
        line_no = content[:m.start()].count('\n') + 1
        findings.append((line_no, "SETE-2 sh/bash -c with " + str(n) + " commands and no 'set -e' inside; exit status reflects only the last command"))

for line_no, msg in findings:
    print(filepath + ":" + str(line_no) + ": " + msg)

sys.exit(1 if findings else 0)
PYEOF
); then
	echo "$CUSTOM_OUT" >&2
	HAD_ERRORS=1
fi

# If neither shfmt nor shellcheck is installed, warn ONCE so the silent pass
# is no longer silent. A missing tool must not block an edit (would be a worse
# bug than the one this warning surfaces).
if [ "$HAS_SHFMT" -eq 0 ] && [ "$HAS_SHELLCHECK" -eq 0 ]; then
	echo "formatters/sh: shfmt and shellcheck not installed; install via 'apt install shfmt shellcheck' (or equivalent). Custom checks still ran." >&2
fi

exit $HAD_ERRORS