polysafe-gitfixer

A polyglot implementation of a git backup merger tool, where each component is written in the language that provides the strongest safety guarantees for that component’s concerns.

1. Overview

polysafe-gitfixer helps you manage git repository backups by:

1. Scanning a directory tree for git repositories

2. Finding backup directories (-backup, .backup-*)

3. Matching backups to their corresponding repos

4. Diffing backup vs repo contents

5. Offering interactive merge/replace/delete options

6. Maintaining an append-only audit log

7. Handling failures gracefully via OTP supervision

2. Architecture

┌─────────────────────────────────────────────────────────────────────────────┐
│ COMPONENT MAP │
├─────────────────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────────┐ ┌─────────────────┐ │
│ │ Haskell │ │ Nickel │ │
│ │ TUI/CLI │◄────────│ Config │ │
│ │ (Brick) │ │ (schemas) │ │
│ └────────┬────────┘ └─────────────────┘ │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────┐ │
│ │ Elixir/OTP │ │
│ │ Orchestration & Supervision │ │
│ └───┬─────────────────┬─────────────────┬─────────────────┬───┘ │
│ │ │ │ │ │
│ ▼ ▼ ▼ ▼ │
│ ┌─────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐ │
│ │ Idris │ │ Haskell │ │ Rust │ │ Rust │ │
│ │Workflow │ │ Diff │ │ Git │ │ F/S │ │
│ │ State │ │ Engine │ │ Ops │ │ Ops │ │
│ └─────────┘ └──────────┘ └──────────┘ └──────────┘ │
│ │
│ ┌──────────────────────────────┐ │
│ │ Rust │ │
│ │ Capability & Audit Layer │ │
│ └──────────────────────────────┘ │
└─────────────────────────────────────────────────────────────────────────────┘

3. Components

Component	Language	Safety Guarantee
Configuration	Nickel	Schema validation, typed defaults
Capability & Audit	Rust	Path traversal prevention, tamper-evident logging
Filesystem Ops	Rust	RAII, atomic transactions, rollback on failure
Git Operations	Rust	Error handling, effect tracking
Diff Engine	Haskell	Totality, streaming for large files
Workflow State	Idris 2	Typestate (can’t call operations in wrong order)
Orchestration	Elixir/OTP	Fault isolation, supervision trees
TUI/CLI	Haskell (Brick)	Elm Architecture, exhaustive event handling

4. Quick Start

4.1. Prerequisites

• Rust 1.75+ (via rustup)

• Haskell GHC 9.4+, Cabal 3.8+

• Elixir 1.15+, OTP 26+

• Nickel 1.4+ (optional, for config validation)

• Idris 2 0.6+ (optional, Haskell fallback available)

4.2. Build

# Build all components
make all
# Run tests
make test# Build individual components
make rust # Rust crates only
make haskell # Haskell components only
make elixir # Elixir orchestrator only

5. Project Structure

polysafe-gitfixer/
├── config/ # Nickel configuration schemas
├── crates/ # Rust components
│ ├── capability/ # Path safety & audit logging
│ ├── fs_ops/ # Transactional filesystem operations
│ ├── git_ops/ # Git repository operations
│ └── polysafe_nifs/ # Rustler NIFs for Elixir
├── haskell/ # Haskell components
│ ├── diff-engine/ # Tree/file diffing
│ └── tui/ # Terminal UI
├── idris/ # Idris 2 workflow state machine
├── elixir/ # Elixir orchestrator
├── .well-known/ # RSR protocol files
└── test/ # Integration tests

6. Safety Philosophy

Each component uses the language with the strongest safety guarantees for its specific concerns:

Rust (capability, fs_ops, git_ops)

Memory safety without garbage collection, RAII for deterministic cleanup, strong ownership model prevents data races.

Haskell (diff-engine, tui)

Strong static typing, totality checking, lazy evaluation for streaming large files, Elm Architecture for exhaustive event handling.

Elixir/OTP (orchestrator)

"Let it crash" philosophy with supervision trees, process isolation, fault-tolerant by design.

Idris 2 (workflow)

Dependent types enable typestate patterns where invalid states are unrepresentable at compile time.

Nickel (configuration)

Schema validation with contracts, preventing configuration errors before runtime.

7. Contributing

We welcome contributions! See CONTRIBUTING for:

• The Tri-Perimeter Contribution Framework (TPCF)

• Development setup instructions

• Code style guidelines

• How to submit merge requests

8. Documentation

• Security Policy - Vulnerability reporting

• Code of Conduct - Community standards

• Governance - Decision-making process

• Maintainers - Project leadership

9. License

This project is licensed under the Mozilla Public License, v. 2.0. See the LICENSE file for details.

SPDX-License-Identifier: CC-BY-SA-4.0

10. Acknowledgments

• Rhodium Standard - Repository standards

• git2-rs - Rust bindings for libgit2

• ring - Cryptographic primitives

---

This project follows the Rhodium Standard Repositories specification.

11. Architecture

See TOPOLOGY.md for a visual architecture map and completion dashboard.