Java: Suppress protobuf warnings

Its too hard to bring maven to accept protobuf, bash is easier. But protobuf files generate warning. Seems not possible to ignore the warning everywhere. SuppressWarnings in packe-info.java on package level is not possible. This script adds a SuppressWarnings to all generated protobuf files and can be used as step after protoc invocation. Inegrates well with bash-based workflows.

from pathlib import Path

def main():
    proto_dir = Path("src/main/proto")
    java_dir = Path("src/main/java")
    assert proto_dir.is_dir(), f"{proto_dir} is not a directory"

    # Step 1: Collect packages
    package_paths = set()
    for proto_file_path in proto_dir.glob("**/*.proto"):
        package_path = proto_file_path.parent
        java_package_path = java_dir / package_path.relative_to(proto_dir)
        package_paths.add(java_package_path)

    # Step 2: Get all java files
    java_file_paths = set()
    for package in package_paths:
        for java_file_path in package.glob("**/*.java"):
            java_file_paths.add(java_file_path)

    # Step 3: Add SuppressWarnings annotation
    for java_file_path in java_file_paths:
        with open(java_file_path, "r") as file:
            lines = file.readlines()

        if not is_proto_generated_file(lines):
            continue        
        
        insert_supress_warning(lines)     
       
        with open(java_file_path, "w") as file:
            for line in lines:
                file.write(line)

def is_proto_generated_file(lines: list[str]):
    for line in lines:
        if not line.strip():
            continue
        if "Generated by the protocol buffer compiler" in line:
            return True
        return False

        
def insert_supress_warning(lines: list[str]):
    for i, line in enumerate(lines):
        if '@SuppressWarnings({"all"})' in line:
            return
        if "public final class" in line:
            lines.insert(i, '@SuppressWarnings({"all"})\n')
            return

main()