#!/usr/bin/env python3

# Copyright (c) 2026 Zededa, Inc.

# SPDX-License-Identifier: Apache-2.0

"""Filter a Go coverage text file to remove entries with conflicting NumStmt.

When coverage data from different binary builds is merged, the same source

block may appear with different NumStmt values (e.g. after a code change).

'go tool cover -func' rejects such files with "inconsistent NumStmt".

This script keeps the first occurrence of each (file, range) key and drops

subsequent lines where NumStmt differs, printing a warning to stderr.

Usage:

python3 filter_coverage_conflicts.py <input> [output]

python3 filter_coverage_conflicts.py < input.txt > output.txt

"""

import sys

def filter_conflicts(infile, outfile):

"""Read coverage lines from infile, write deduplicated lines to outfile."""

seen = {} # key -> numstmt of first occurrence

dropped = 0

for line in infile:

stripped = line.rstrip('\n')

if not stripped or stripped.startswith('mode:'):

outfile.write(line)

continue

parts = stripped.split()

if len(parts) != 3:

outfile.write(line)

continue

key, numstmt, _ = parts

prev = seen.get(key)

if prev is None:

seen[key] = numstmt

outfile.write(line)

elif prev != numstmt:

dropped += 1

if dropped <= 10:

print(

f"warning: dropping {key} numstmt={numstmt} "

f"(conflicts with first-seen numstmt={prev})",

file=sys.stderr,

)

else:

outfile.write(line)

if dropped > 10:

print(

f"warning: {dropped} conflicting entries dropped in total",

file=sys.stderr,

)

elif dropped:

print(f"warning: {dropped} conflicting entries dropped", file=sys.stderr)

def main():

"""Parse arguments and invoke filter_conflicts on the specified files."""

args = sys.argv[1:]

if args and args[0] in ('-h', '--help'):

print(__doc__)

sys.exit(0)

if not args:

filter_conflicts(sys.stdin, sys.stdout)

elif len(args) == 1:

with open(args[0], encoding='utf-8') as inf:

filter_conflicts(inf, sys.stdout)

elif len(args) == 2:

with open(args[0], encoding='utf-8') as inf, open(args[1], 'w', encoding='utf-8') as outf:

filter_conflicts(inf, outf)

else:

print(f"usage: {sys.argv[0]} [input [output]]", file=sys.stderr)

sys.exit(1)

if __name__ == '__main__':

main()