Debugging Git-LFS

When working with Git Large File Storage (Git-LFS), you might occasionally encounter issues, especially with the smudge filter. This guide provides a structured approach to debugging such problems, particularly on Windows.

Debugging the smudge Filter

Problem Overview

If you are experiencing long delays, hangs, or unresponsive behavior in SmartGit during repository refresh operations, it could be related to the Git-LFS smudge filter. This typically manifests with log entries similar to the following in SmartGit’s log file:

killing 'c:\app\tools\git\usr\bin\sh.exe -c "git-lfs smudge ...

The following steps will help you debug and isolate the issue.

Step-by-Step Debugging on Windows

Assume the problematic file is located at dir/file and your Git installation is located at C:\Portable\Git.

1. Prepare the Environment

• Open a command prompt.

• Navigate to the root directory of your Git repository:

  cd path\to\your\repository
  

• Adjust the PATH to ensure the correct Git executable is used:

  SET PATH=C:\Portable\Git;C:\Portable\Git\mingw64\bin;%PATH%
  

2. Identify the File’s SHA

Run the following command to locate the Git-LFS entry for the file:

git ls-files -s | grep dir/file

• Note the SHA provided in the output. This SHA represents the Git pointer file.

3. Inspect the Git-LFS Pointer

Retrieve the Git object associated with the file:

git show <sha> > out-lfs

• Open the out-lfs file and verify that it contains content resembling this format:

  version https://git-lfs.github.com/spec/v1
  oid sha256:520928654e8615ebc33bfae21f91cea3a5d04a2883af00c409f0a5f24950059b
  size 1048576
  

This confirms that the file is being tracked by Git-LFS.

4. Run the smudge Filter Manually

Test the smudge filter in isolation to observe its behavior:

C:\Portable\Git\usr\bin\sh.exe -c "git-lfs smudge -- 'dir/file'" < out-lfs > out-blob

• This command simulates the smudge process that (Smart)Git would normally perform during checkout.
• Review out-blob to ensure the expected file content is present and no errors occurred.

Final Notes

• This procedure is particularly useful for isolating whether the issue lies within Git-LFS, the Git executable, or SmartGit’s handling of Git commands.
• If the manual smudge operation succeeds but SmartGit continues to hang, the problem may be related to the Git integration within SmartGit or environmental path configurations.

Additional Tips

• Try with SmartGit’s bundle Git Executable
• Always ensure you are using compatible versions of Git and Git-LFS.
• Consider updating Git if persistent issues occur.
• Review SmartGit’s settings to verify the configured Git executable matches the one you are debugging with.