Installs pre-commit hooks for OCaml projects that run dune fmt automatically
Initial commit: precommit - pre-commit hook initialization for OCaml projects
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.gitignore
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.gitignore
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.ocamlformat
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.ocamlformat
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version=0.28.1
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LICENSE.md
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LICENSE.md
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MIT License
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Copyright (c) 2025 Thomas Gazagnaire
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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README.md
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README.md
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# precommit
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Pre-commit hook initialization for OCaml projects.
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## Overview
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This tool sets up pre-commit hooks for OCaml projects:
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- **dune-format**: Automatically formats OCaml code using `dune fmt --auto`
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- **remove-claude-attribution**: Removes Claude co-author lines and rejects emojis in commit messages
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## Installation
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```
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opam install precommit
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```
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## Usage
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Run in an OCaml project directory (where `dune-project` exists):
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```bash
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precommit init
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```
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This creates:
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- `.pre-commit-config.yaml` - Hook configuration
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- `.hooks/remove-claude-lines.py` - Commit message filter
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And runs `pre-commit install` to activate the hooks.
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### Dry run
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To see what would be created without making changes:
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```bash
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precommit init --dry-run
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```
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## Requirements
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- [pre-commit](https://pre-commit.com/) must be installed
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- Python 3 (for the commit message hook)
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- dune (for code formatting)
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## License
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MIT License. See [LICENSE.md](LICENSE.md) for details.
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bin/dune
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bin/dune
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bin/main.ml
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bin/main.ml
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(** CLI for pre-commit hook initialization. *)
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open Cmdliner
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let dry_run =
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let doc = "Print what would be done without making changes." in
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Arg.(value & flag & info [ "n"; "dry-run" ] ~doc)
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let init_cmd =
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let doc = "Initialize pre-commit hooks for an OCaml project." in
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let info = Cmd.info "init" ~doc in
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let term =
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Term.(
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const (fun dry_run ->
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match Precommit.init ~dry_run () with
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| Ok () ->
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if not dry_run then
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print_endline "Pre-commit hooks initialized successfully.";
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`Ok ()
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| Error msg ->
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Printf.eprintf "Error: %s\n" msg;
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`Error (false, msg))
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$ dry_run)
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in
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Cmd.v info (Term.ret term)
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let default_cmd =
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let doc = "Pre-commit hook initialization for OCaml projects." in
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let info = Cmd.info "precommit" ~version:"0.1.0" ~doc in
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let default = Term.(ret (const (`Help (`Pager, None)))) in
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Cmd.group info ~default [ init_cmd ]
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let () = exit (Cmd.eval default_cmd)
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dune-project
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dune-project
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(lang dune 3.0)
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(name precommit)
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(generate_opam_files true)
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(license MIT)
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(authors "Thomas Gazagnaire <thomas@gazagnaire.org>")
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(maintainers "Thomas Gazagnaire <thomas@gazagnaire.org>")
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(homepage "https://tangled.org/@gazagnaire.org/ocaml-precommit")
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(bug_reports "https://tangled.org/@gazagnaire.org/ocaml-precommit/issues")
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(package
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(name precommit)
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(synopsis "Pre-commit hook initialization for OCaml projects")
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(description
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"A CLI tool to initialize pre-commit hooks for OCaml projects. Sets up \
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automatic formatting with dune fmt and removes Claude attribution from \
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commit messages.")
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(depends
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(ocaml (>= 4.08))
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(cmdliner (>= 1.2))
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(ocamlformat :with-dev-setup)
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(alcotest :with-test)))
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lib/precommit.ml
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lib/precommit.ml
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(** Pre-commit hook initialization for OCaml projects. *)
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let pre_commit_config =
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{|repos:
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- repo: local
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hooks:
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- id: dune-format
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name: Auto format with dune
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entry: dune fmt --auto
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language: system
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files: \.(ml|mli|mll|mly)$
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stages: [pre-commit]
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pass_filenames: false
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- id: remove-claude-attribution
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name: Remove Claude attribution from commit message
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entry: python3 .hooks/remove-claude-lines.py
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language: system
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stages: [commit-msg]
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|}
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let remove_claude_lines =
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{|#!/usr/bin/env python3
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import sys
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import re
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def has_emoji(text):
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# Unicode ranges for emojis
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emoji_pattern = re.compile(
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"["
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"\U0001F600-\U0001F64F" # emoticons
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"\U0001F300-\U0001F5FF" # symbols & pictographs
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"\U0001F680-\U0001F6FF" # transport & map symbols
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"\U0001F1E0-\U0001F1FF" # flags (iOS)
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"\U00002702-\U000027B0" # dingbats
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"\U000024C2-\U0001F251"
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"]+", flags=re.UNICODE)
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return bool(emoji_pattern.search(text))
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def main():
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commit_msg_file = sys.argv[1]
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with open(commit_msg_file, 'r', encoding='utf-8') as f:
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lines = f.readlines()
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# Check for emojis in the commit message
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commit_text = ''.join(lines)
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if has_emoji(commit_text):
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print("Error: Commit message contains emojis, which are not allowed.", file=sys.stderr)
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return 1
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filtered_lines = [line for line in lines if 'claude' not in line.lower()]
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with open(commit_msg_file, 'w', encoding='utf-8') as f:
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f.writelines(filtered_lines)
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return 0
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if __name__ == '__main__':
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sys.exit(main())
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|}
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let file_exists path = Sys.file_exists path
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let mkdir_p path =
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if not (file_exists path) then Unix.mkdir path 0o755
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let write_file ~dry_run path content =
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if dry_run then Printf.printf "Would create %s\n" path
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else begin
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let oc = open_out path in
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output_string oc content;
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close_out oc
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end
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let chmod_exec ~dry_run path =
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if dry_run then Printf.printf "Would chmod +x %s\n" path
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else Unix.chmod path 0o755
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let run_command ~dry_run cmd =
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if dry_run then begin
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Printf.printf "Would run: %s\n" cmd;
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0
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end
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else Sys.command cmd
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let init ~dry_run () =
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(* Check if we're in an OCaml project *)
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if not (file_exists "dune-project") then
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Error "No dune-project found. Run this from an OCaml project root."
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else begin
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(* Create .hooks directory *)
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if dry_run then Printf.printf "Would create .hooks/\n"
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else mkdir_p ".hooks";
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(* Write .pre-commit-config.yaml *)
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write_file ~dry_run ".pre-commit-config.yaml" pre_commit_config;
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(* Write .hooks/remove-claude-lines.py *)
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write_file ~dry_run ".hooks/remove-claude-lines.py" remove_claude_lines;
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chmod_exec ~dry_run ".hooks/remove-claude-lines.py";
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(* Run pre-commit install *)
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let cmd = "pre-commit install --hook-type pre-commit --hook-type commit-msg" in
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let exit_code = run_command ~dry_run cmd in
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if exit_code <> 0 then
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Error (Printf.sprintf "pre-commit install failed with exit code %d" exit_code)
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else
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Ok ()
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end
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lib/precommit.mli
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lib/precommit.mli
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(** Pre-commit hook initialization for OCaml projects. *)
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(** {1 Templates} *)
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val pre_commit_config : string
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(** The content of [.pre-commit-config.yaml]. *)
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val remove_claude_lines : string
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(** The content of [.hooks/remove-claude-lines.py]. *)
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(** {1 Operations} *)
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val init : dry_run:bool -> unit -> (unit, string) result
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(** [init ~dry_run ()] initializes pre-commit hooks in the current directory.
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Creates [.pre-commit-config.yaml] and [.hooks/remove-claude-lines.py],
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then runs [pre-commit install].
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If [dry_run] is [true], prints what would be done without making changes. *)
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precommit.opam
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precommit.opam
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# This file is generated by dune, edit dune-project instead
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opam-version: "2.0"
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synopsis: "Pre-commit hook initialization for OCaml projects"
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description:
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"A CLI tool to initialize pre-commit hooks for OCaml projects. Sets up automatic formatting with dune fmt and removes Claude attribution from commit messages."
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maintainer: ["Thomas Gazagnaire <thomas@gazagnaire.org>"]
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authors: ["Thomas Gazagnaire <thomas@gazagnaire.org>"]
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license: "MIT"
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homepage: "https://tangled.org/@gazagnaire.org/ocaml-precommit"
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bug-reports: "https://tangled.org/@gazagnaire.org/ocaml-precommit/issues"
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depends: [
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"dune" {>= "3.0"}
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"ocaml" {>= "4.08"}
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"cmdliner" {>= "1.2"}
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"ocamlformat" {with-dev-setup}
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"alcotest" {with-test}
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"odoc" {with-doc}
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]
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build: [
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["dune" "subst"] {dev}
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[
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"dune"
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"build"
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"-p"
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name
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"-j"
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jobs
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"@install"
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"@runtest" {with-test}
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"@doc" {with-doc}
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]
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]
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test/test.ml
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test/test.ml
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let () = Alcotest.run "precommit" Test_precommit.suite
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test/test_precommit.ml
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test/test_precommit.ml
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(** Tests for precommit. *)
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let contains s sub =
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let len = String.length sub in
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let rec check i =
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if i + len > String.length s then false
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else if String.sub s i len = sub then true
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else check (i + 1)
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in
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check 0
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let test_pre_commit_config_valid () =
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let config = Precommit.pre_commit_config in
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Alcotest.(check bool) "starts with repos:" true (String.sub config 0 6 = "repos:");
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Alcotest.(check bool) "contains dune-format" true (contains config "dune-format");
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Alcotest.(check bool) "contains commit-msg" true (contains config "commit-msg")
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let test_remove_claude_lines_valid () =
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let script = Precommit.remove_claude_lines in
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Alcotest.(check bool) "is python script" true (String.sub script 0 2 = "#!");
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Alcotest.(check bool) "filters claude lines" true (contains script "'claude'");
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Alcotest.(check bool) "checks emojis" true (contains script "has_emoji")
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let suite =
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[
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( "templates",
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[
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Alcotest.test_case "pre_commit_config valid" `Quick
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test_pre_commit_config_valid;
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Alcotest.test_case "remove_claude_lines valid" `Quick
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test_remove_claude_lines_valid;
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] );
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]