# ⚠️ IMPORTANT SAFETY NOTE - LOCAL CI SCRIPT

## Problem Identified and Fixed

The original version of `local_ci.sh` contained a **destructive command** that was damaging Rust installations:

### The Culprit
```bash
cargo update -Z minimal-versions
```

This command **modifies your Cargo.lock file** by downgrading all dependencies to their minimal compatible versions. This can:
- Break your project's dependency resolution
- Cause compilation failures
- Corrupt your local development environment
- Require reinstalling Rust in severe cases

## What We Fixed

1. **Removed the dangerous command** - The minimal versions check is now commented out
2. **Added Cargo.lock protection** - The script now:
   - Backs up Cargo.lock before running
   - Checks if it was modified
   - Automatically restores the original if any changes detected
3. **Made PATH modifications safer** - Only adds cargo to PATH if not already present
4. **Added safety documentation** - Clear warnings about what the script does/doesn't do

## Current Safety Guarantees

The updated `local_ci.sh` script now:
- ✅ **NEVER** modifies Cargo.lock
- ✅ **NEVER** runs `cargo update` or `cargo install`
- ✅ **NEVER** modifies your Rust installation
- ✅ **NEVER** changes dependencies
- ✅ Automatically restores Cargo.lock if any command tries to modify it
- ✅ Only runs read-only validation commands

## Safe Commands Used

All commands in the script are now read-only:
- `cargo fmt --check` (check only, doesn't modify)
- `cargo clippy` (linting only)
- `cargo build` (creates artifacts in target/, doesn't modify source)
- `cargo test` (runs tests, doesn't modify)
- `cargo check` (validation only)
- `cargo audit` (security check only)

## If You Had Issues

If you experienced Rust installation corruption:
1. The minimal versions command was the cause
2. It's now safely disabled
3. Your environment should be safe to use now

## Usage

The script is now safe to run:
```bash
./scripts/local_ci.sh
```

It will validate your code without making any destructive changes to your environment.

---

**Version**: Fixed on 2025-08-29
**Issue**: Cargo minimal versions command was corrupting dependencies
**Status**: RESOLVED - Script is now safe