Configurable git-wrapper support (yadm, chezmoi git, ...) sharing the git filter pipeline

[cderv]

Context

RTK currently has two shapes for git wrappers:

1. Command rewriting via rewrite_prefixes — yadm was added this way (feat(discover): treat yadm commands like git #940), then broken (yadm incorrectly rewritten to rtk git (yadm is not a git alias) #2077) and is being removed (fix: remove yadm from git rewrite rules #2078) because yadm uses --work-tree=$HOME plus a bare repo, so rtk git status runs in the wrong cwd.
2. Standalone TOML filter — src/filters/yadm.toml reimplements a subset of git's filtering (strip blank/hint lines, truncate, max_lines). Filtered, but only partial parity with the Rust git filter.

A third class — chezmoi's chezmoi git <subcmd> — has the same working-directory-wrapper shape as yadm and is currently unfiltered. See #2117 for the chezmoi-specific scope.

The duplication

src/filters/yadm.toml re-creates a fraction of what src/cmds/git/git.rs already does. PR #436's chezmoi handler reimplements git diff parsing for chezmoi diff. Each wrapper carries its own divergent copy of git output logic, and the more wrappers RTK adopts the more this drift compounds.

Possible directions

Two shapes that came to mind, neither necessarily right:

• A. TOML filter pipeline inheritance. Extend the TOML schema with an inherit_pipeline_from = "git" (or similar) field that runs the input through an existing Rust filter pipeline before the TOML line-based stages. Lets yadm.toml and a future chezmoi-git.toml share git's parsing while keeping wrapper-specific tweaks.

• B. Command-level wrapper config. A [wrappers] section in config.toml, e.g.

[wrappers.chezmoi-git]
match = "^chezmoi git\\s+(.*)"
inner_cmd = "git"
filter_as = "rtk git"   # apply git's output filter; do not rewrite the command

The runtime would still run chezmoi git status as-is, capture stdout, and route it through git's output filter. No command rewriting — avoids the #2077 trap.

Both shapes preserve working-directory semantics, which the existing rewrite_prefixes mechanism doesn't (per #2077, #2078).

Constraints

• Wrappers set cwd implicitly (yadm via env, chezmoi via source-path). The wrapped git filter must operate on captured output, not re-invoke rtk git in $PWD.
• rewrite_prefixes handles env-style wrappers (poetry run cargo) but is the wrong tool for wd-changing wrappers.

Motivation

• yadm output filtering, currently limited to what TOML can express
• chezmoi git, completely unfiltered today (~145 hits in one user's session — see feat: chezmoi dotfile manager support — and the chezmoi git gap #2117)
• Future wrappers: vcsh, mr run -j1 git (myrepos), other dotfile/multirepo helpers

Open questions

• Is this worth solving generically now, or wait until a third wrapper materializes?
• If generic: A, B, both, or some other shape?
• Where should the wrapper definitions live — built-in TOML, config.toml, or both with priority?

CONTRIBUTING.md suggests discussing core changes before filing them as PRs, so opening this as an RFC rather than an issue.

Related

• yadm incorrectly rewritten to rtk git (yadm is not a git alias) #2077 — yadm rewritten to rtk git, breaks on bare-repo cwd
• fix: remove yadm from git rewrite rules #2078 — PR removing yadm from rewrite_prefixes
• feat(chezmoi): add chezmoi dotfile manager support (80-90% token savings) #436 — chezmoi support PR (reimplements git diff parsing)
• feat: chezmoi dotfile manager support — and the chezmoi git gap #2117 — chezmoi support feature request, including the chezmoi git gap

Environment

• rtk 0.42.0