verify-formatting-only

#!/usr/bin/env python3

#import argparse
# TODO: walk through building; disabling debug; prompt for built jar location
import zipfile
import tempfile
import os.path
import filecmp
import subprocess

post_merge = zipfile.ZipFile("post-merge.jar")
pre_merge = zipfile.ZipFile("pre-merge.jar")

post_merge_names = post_merge.namelist()
pre_merge_names = pre_merge.namelist()

added_post_merge = set(post_merge_names).difference(pre_merge_names)
removed_post_merge = set(pre_merge_names).difference(post_merge_names)
if added_post_merge or removed_post_merge:
    print("Different files are present after the merge than before.")

    if added_post_merge:
        print("Elements added in the merge:")
        for element in added_post_merge:
            print("  * {}".format(element))

    if removed_post_merge:
        print("Elements removed in the merge:")
        for element in removed_post_merge:
            print("  * {}".format(element))

    print("Verification failed.")
    exit(1)

differing_files = []
with tempfile.TemporaryDirectory("post_merge") as post_merge_dir:
    with tempfile.TemporaryDirectory("pre_merge") as pre_merge_dir:
        for filename in post_merge_names:
            post_merge.extract(filename, path=post_merge_dir)
            pre_merge.extract(filename, path=pre_merge_dir)

            post_merge_path = os.path.join(post_merge_dir, filename)
            pre_merge_path = os.path.join(pre_merge_dir, filename)

            if os.path.isdir(post_merge_path):
                continue

            if not filecmp.cmp(post_merge_path, pre_merge_path, shallow=False):
                if filename == "./META-INF/MANIFEST.MF":
                    print("Manifest is different; this is expected.")
                    print("Please review the differences:")
                    subprocess.call(["diff", pre_merge_path, post_merge_path])
                else:
                    print("{} differs.".format(filename))
                    differing_files.append(filename)

if differing_files:
    print('Verification failed. Ensure that debug="off" in the javac '
          'invocation.')
    exit(1)

print("Verification successful.")