rtk-ai/rtk

rtk git diff prepends diffstat, breaking git apply

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#1081 opened on Apr 8, 2026

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bugeffort-smallfilter-qualitygood first issue

Description

Problem

rtk git diff prepends a diffstat summary before the actual diff output. This breaks git apply because the diffstat lines are not valid patch format.

Example output:

CLAUDE.local.md   | 11 +++++++++++
 src/lib/badges.ts | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/CLAUDE.local.md b/CLAUDE.local.md
index 15f4045..b9901bd 100644
...

The first 3 lines (file stats + summary) are not part of the unified diff format. When piping to git apply, it fails to parse.

Impact

This is particularly problematic when using Claude Code agents in worktrees. The typical workflow is:

  1. Spawn an agent in a worktree
  2. Extract its changes with git diff
  3. Apply the patch to the main worktree with git apply

Step 3 fails because of the prepended diffstat. The current workaround is:

git diff --no-color -U3 2>/dev/null | sed -n '/^diff --git/,$p' > /tmp/patch.patch

Expected behavior

rtk git diff should output a clean unified diff without prepending a diffstat, so the output remains compatible with git apply, git am, and other tools that consume patches.

Alternatively, the diffstat could be sent to stderr instead of stdout.

Environment

  • rtk 0.35.0
  • Hook version: 3 (freshly updated via rtk init -g)
  • macOS (Apple Silicon)
  • Claude Code

Contributor guide

Tech stack
rust
Domain
clitooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
basic Rustunderstanding of git diff output format
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75
Research direction
Examine the git diff command implementation, likely in src/cli/git diff.rs or similar. The current code prepends a diffstat summary to stdout. Remove the diffstat lines or redirect them to stderr so only the unified diff is printed. Ensure the output is compatible with git apply. Test using the provided example and verify the patch applies cleanly.