Sandbox RW path grants not honored by JVM processes spawned from Copilot CLI

Describe the bug

Summary

Sandbox path RW grants configured via /sandbox (e.g. ~/.m2/repository) are not honored by JVM/Java processes, even though the same path is fully writable for plain shell commands. Any Java-based tool (Maven, javac-compiled programs, etc.) fails with Operation not permitted on file/directory writes under a granted path, blocking real-world workflows like mvn clean compile.

Environment

• CLI version: 1.0.80
• OS: macOS (Darwin), aarch64
• Granted sandbox path: ~/.m2/repository (Read/Write)

Real-world impact

Running mvn clean compile in a multi-module Maven project fails identically — both the cyclonedx-maven-plugin and Maven core's own DefaultTrackingFileManager/DefaultUpdateCheckManager (writing resolver-status.properties for resolved dependency metadata under ~/.m2/repository/...) throw the same FileSystemException: Operation not permitted, even though the parent directories were freshly, successfully created by shell mkdir moments earlier in the same session.

Suspected root cause

The sandbox's file-access enforcement appears to differ by process/executable type rather than purely by path: shell built-ins (touch, mkdir) inherit the granted RW access, but JVM processes (java, and therefore javac, mvn) invoking sun.nio.fs.UnixFileSystemProvider (NIO FileChannel.open/Files.createDirectory) are denied on the identical path/grant.

Affected version

1.0.80

Steps to reproduce the behavior

1. In /sandbox, confirm ~/.m2/repository (or any path) is granted Read/Write.

2. From the CLI's shell tool, confirm plain shell operations succeed on that path:
   mkdir -p ~/.m2/repository/zz-test-dir && echo OK # succeeds
   touch ~/.m2/repository/zz-test-dir/file.txt && echo OK # succeeds

3. Compile and run a minimal Java program that writes a file under the same granted path via NIO:

    mkdir -p ~/.m2/repository/zz-test-dir
   

   import java.nio.channels.FileChannel;
   import java.nio.file.*;
   
   import static java.nio.file.StandardOpenOption.*;
   
   public class WriteTest {
       public static void main(String[] args) throws Exception {
           Path p = Paths.get(System.getProperty("user.home") + "/.m2/repository/zz-test-dir/javatest.properties");
           try (FileChannel ch = FileChannel.open(p, CREATE, WRITE)) {
               System.out.println("JAVA WRITE OK");
           }
       }
   }
   

   javac WriteTest.java && java WriteTest
   

4. Actual result:

Exception in thread "main" java.nio.file.FileSystemException: .../zz-test-dir/javatest.properties: Operation not permitted
   at java.base/sun.nio.fs.UnixFileSystemProvider.newFileChannel
   at java.base/java.nio.channels.FileChannel.open
   at WriteTest.main(WriteTest.java:7)

Expected behavior

"JAVA WRITE OK" printed.

Additional context

No response

Bắt đầu bằng cách tái hiện sự khác biệt giữa thao tác ghi của shell và ví dụ Java NIO FileChannel.open trên một đường dẫn được cấp quyền thông qua /sandbox. Theo dõi việc thực thi kiểm soát truy cập tệp của sandbox đối với các tiến trình JVM được khởi chạy và so sánh với các lệnh shell. Được xem là hoàn tất khi thao tác ghi Java thành công và mvn clean compile có thể ghi vào ~/.m2/repository mà không gặp Operation not permitted.