Identify strings in en-US .strings files but not available in Strings.swift

unused_strings_fxios.py

#!/usr/bin/env python3
"""
Script to find unused localized string IDs in .strings files under en-US.lproj
folders by checking their definitions in firefox-ios/Shared/Strings.swift.
"""

import re
import sys
from pathlib import Path


def find_strings_files(root: Path):
    """Recursively find all .strings files in en-US.lproj directories."""
    search_path = root / "firefox-ios"
    return search_path.rglob("en-US.lproj/*.strings")


def extract_keys_from_strings_file(strings_path: Path, root: Path):
    """Extract all keys from a .strings file."""
    pattern = re.compile(r'^\s*"([^"]+)"\s*=')
    keys = []
    strings_rel_path = strings_path.relative_to(root)
    with strings_path.open("r", encoding="utf-8") as f:
        for line in f:
            match = pattern.match(line)
            if match:
                keys.append(f"{strings_rel_path}:{match.group(1)}")
    return keys


def extract_defined_keys_from_swift(swift_path: Path):
    """Extract all keys defined in Strings.swift via MZLocalizedString calls."""
    pattern = re.compile(r'key:\s*"([^"]+)"')
    content = swift_path.read_text(encoding="utf-8")
    return pattern.findall(content)


# List of string IDs to exclude from unused report
excluded_ids = set(
    [
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:NSCameraUsageDescription",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:NSFaceIDUsageDescription",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:NSLocationWhenInUseUsageDescription",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:NSMicrophoneUsageDescription",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:NSPhotoLibraryAddUsageDescription",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:New Private Tab",
        "firefox-ios/Client/en-US.lproj/InfoPlist.strings:Scan QR Code",
        "firefox-ios/Shared/en-US.lproj/Default Browser.strings:DefaultBrowserCard.Button.v2",
        "firefox-ios/Shared/en-US.lproj/Localizable.strings:A username and password are being requested by %@. The site says: %@",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:2GqvPe",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:PzSrmZ-2GqvPe",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:PzSrmZ-eHmH1H",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:PzSrmZ-scEmjs",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:PzSrmZ-xRJbBP",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:ctDNmu",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:eHmH1H",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:eV8mOT",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:eqyNJg",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:fi3W24-2GqvPe",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:fi3W24-eHmH1H",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:fi3W24-scEmjs",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:fi3W24-xRJbBP",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:scEmjs",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:w9jdPK",
        "firefox-ios/WidgetKit/en-US.lproj/WidgetIntents.strings:xRJbBP",
    ]
)


def main(root_dir: Path):
    # Locate Strings.swift
    swift_file = root_dir / "firefox-ios" / "Shared" / "Strings.swift"
    if not swift_file.exists():
        print(f"Error: Strings.swift not found at {swift_file}", file=sys.stderr)
        sys.exit(1)

    # Gather all keys from .strings files
    all_keys = set()
    for strings_file in find_strings_files(root_dir):
        all_keys.update(extract_keys_from_strings_file(strings_file, root_dir))

    # Gather all keys defined in Strings.swift
    defined_keys = set(extract_defined_keys_from_swift(swift_file))

    unused_keys = set()
    # Compute unused keys
    for key in all_keys:
        id = key.split(":")[1]
        if key in excluded_ids:
            continue
        if id not in defined_keys:
            unused_keys.add(key)

    unused_keys = sorted(unused_keys)
    if unused_keys:
        for key in unused_keys:
            print(f"Unused string ID: {key}")
    else:
        print("No unused string IDs found.")


if __name__ == "__main__":
    root = (
        Path(sys.argv[1])
        if len(sys.argv) > 1
        else sys.exit("Provide the path to the Firefox iOS repo.")
    )
    main(root)