allowed-nightly-features

#!/usr/bin/python3
# SPDX-License-Identifier: Apache-2.0

import os
import sys
import toml
import re

# Given a file, this function yields all enabled features in that file.
def yield_features(file):
    file = file.replace('\n', '')
    matches = re.findall(r'#!\[feature\((.+?)\)\]', file)
    for block in matches:
        for feature in block.split(","):
            yield feature.strip()

# Given a root crate directory, this function finds all Cargo entrypoints in it
# and all subcrates.
def yield_paths(root_dir):
    crate_dirs = {root for root, dirs, files in os.walk(root_dir) if 'Cargo.toml' in files}
    for dir in crate_dirs:
        cargo = toml.load(os.path.join(dir, 'Cargo.toml'))

        for bin in cargo.get("bin", [{}]):
            if cargo["package"].get("autobins", int(cargo["package"]["edition"]) >= 2018):
                yield os.path.join(dir, bin.get("path", "src/main.rs"))
            else:
                p = bin.get("path")
                if p is not None:
                    yield os.path.join(dir, p)

        for lib in cargo.get("lib", [{}]):
            yield os.path.join(dir, lib.get("path", "src/lib.rs"))

# Get the input allowed features.
allowed_features = sys.argv[1]
allowed_features = {f.strip() for f in allowed_features.split(',')}

# Get the calling workflow's workspace.
workspace = os.environ.get("GITHUB_WORKSPACE", None)
# Grab all paths to check.
paths_to_check = yield_paths(workspace)

# Check each file for unallowed features.
failure = 0
for path in paths_to_check:
    try:
        f = open(path, 'r')
    except:
        continue
    with f:
        file = f.read()

    unallowed_features = set(yield_features(file)) - allowed_features
    if len(unallowed_features) > 0:
        short_path = path[len(workspace):]
        print(f"{short_path} enables unallowed nightly features:")
        for feature in unallowed_features:
            print(feature)
        failure = 1

# Exit with a failure if we encountered unallowed features.
exit(failure)