Building a Reftable-Compatible Git Smartlog

A native Git implementation that works with any repository backend

November 12, 2025 by Hakan Alpay

The Problem

If you’ve used git-branchless, you know how useful git sl (smartlog) is. It shows a beautiful tree view of your local branches, making it easy to see what you’re working on without the noise of everyone else’s remote branches.

But there’s a catch: git-branchless doesn’t work with reftable repositories.

What is Reftable?

Reftable is a new ref storage backend for Git that improves performance for repositories with many refs. Instead of storing each ref as a separate file (the traditional approach), reftable stores refs in a compact, indexed format. This is especially beneficial for large monorepos.

The problem? Git-branchless relies on the traditional ref storage format and fails on reftable repos.

The Solution: git-smartlog

I built a native Git implementation of smartlog that works with any Git repository, including reftable ones. It uses only Git’s plumbing commands, which are backend-agnostic.

What It Looks Like

Here’s the output of git lg (my alias for git-smartlog):

╔════════════════════════════════════════════════════════════════╗
║  Git Smartlog - Branch-centric repository view           ║
╚════════════════════════════════════════════════════════════════╝

Baseline: master

⋮
◇ 84c4031 10h NGT-3034: utils for drawing bBox on pdp (#82406)
┣━┓
⋮ ◯ 9d76c6d 10h Fix checkout page login redirect to preserve original request URL
⋮ ┃
⋮ ◯ 5041aaf 9h Add DV to control checkout login redirect behavior
⋮ ┃
⋮ ◯ 48737e1 9h Add cxWebCheckoutPreserveUrlOnLogin to serverComponentDynamicValuesList
⋮ ┃
⋮ ◯ d7c3e84 9h Update checkout server component to use withPlatformServerComponentDvClient
⋮ ┃
⋮ ● 0226ab8 8h (ᐅ fix-checkout-login-redirect) Remove unused ServerComponentType import
⋮
◇ bc24a39 4h (master) [CHATPLAT-3915] Update event names for chat disconnect/connect/reconnect events

Key Features

Tree structure with Unicode box-drawing characters (⋮, ◇, ●, ◯, ┣━┓, ┃)
Fork points from master/main (◇)
Branch commits (◯) with the branch head marked (●)
Current branch indicator with arrow: (ᐅ branch-name)
Compact time format (8h, 1d, 5w, 4mo)
Only local branches - no noise from remote branches
Works with reftable repos - uses native Git plumbing commands

How It Works

The implementation uses only Git’s plumbing commands, which work regardless of the ref storage backend:

1. Find All Local Branches

git for-each-ref --format='%(refname:short)' refs/heads

This lists all local branches without relying on filesystem structure.

2. Find Fork Points

For each branch, find where it diverged from master:

git merge-base --fork-point refs/heads/master $branch

This gives us the commit where the branch forked off.

3. Get Branch Commits

Get all commits unique to the branch:

git log --format='%h|%ar|%s' $branch ^master

The key optimization here: we get the hash, date, and message in one Git call instead of calling git log separately for each commit.

4. Render the Tree

The script processes each branch and renders:

Fork point (◇) with timestamp
Commits in the branch (◯) in chronological order
Branch head (●) with branch name
Current branch gets an arrow indicator (ᐅ)

Performance Optimizations

The initial implementation was slow because it called Git commands for every commit. Here are the optimizations:

Batch commit data: One git log call per branch instead of one per commit
Eliminate redundant calls: Since we reverse the commit list, the first commit is always the branch head - no need to call git rev-parse to check
In-memory caching: Store branch head hash in a variable instead of calling Git repeatedly

These optimizations reduced the number of Git subprocess calls from O(commits) to O(branches).

Installation

Clone the repo:

git clone https://github.com/Kimeiga/dotfiles.git
cd dotfiles

Add the git-spells directory to your PATH in your shell config:

# In ~/.zshrc or ~/.bashrc
export PATH="$HOME/path/to/dotfiles/git-spells:$PATH"

Add the alias to your .gitconfig:

git config --global alias.lg '!git-smartlog'

Use it:

git lg

Code

Main script: git-spells/git-smartlog
Test suite: git-spells/git-smartlog-test
Documentation: git-spells/README.md

Usage

# Basic usage
git lg

# Verbose mode (shows commit author)
git lg -v

# Include remote branches
git lg -r

# Show help
git lg -h

Why Not Just Use git log —graph?

You might wonder: “Can’t you just use git log --graph?”

The problem with git log --graph is that it shows all branches by default, including:

Remote branches from other developers
Release branches
Tags
Merge commits cluttering the view

Even with filters like --branches --not --remotes, you lose the master commits that serve as fork points, resulting in a linear history instead of a tree.

Git-smartlog solves this by:

Showing only local branches
Including master commits as fork points (◇)
Hiding irrelevant master history
Clearly marking which commits belong to which branch

Comparison with git-branchless

Feature	git-branchless	git-smartlog
Works with reftable	❌	✅
Tree visualization	✅	✅
Shows local branches only	✅	✅
Performance	Excellent (Rust)	Good (Bash + Git)
Dependencies	Rust binary	Just Git + Bash
Customizable	Limited	Easy to modify

Future Improvements

Possible enhancements:

Add color customization options
Support for showing stashes
Integration with Git worktrees
Option to show commit authors inline
Configurable baseline branch (not just master/main)

Conclusion

Building git-smartlog taught me a lot about Git’s internals and the importance of using the right abstractions. By using Git’s plumbing commands instead of relying on filesystem structure, we created a tool that works across different Git backends.

If you work with reftable repositories or just want a lightweight alternative to git-branchless, give git-smartlog a try!

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