# Bazel Dependency Vendoring (Reference Cache)

This project uses a "Reference Cache" strategy for Bazel dependencies to allow AI agents and developers to inspect external source code without impacting build stability or concurrency.

## The Strategy

1.  **Shared Location:** Dependencies are vendored into a shared directory **outside** the workspace (e.g., `../yesod_vendored_deps`).
2.  **Symlink:** The local `vendor` directory is a symlink to that shared location.
3.  **Read-Only:** This directory is intended for **reading and searching** source code.
4.  **No Build Impact:** Standard Bazel builds (`bazel build //...`) do **NOT** use this directory (they use the standard internal Bazel cache). This prevents concurrency issues when multiple git worktrees run builds simultaneously.

## Setup for New Worktrees

If you are setting up a new git worktree, simply create the symlink:

```bash
# Assuming the shared vendor dir is at ../yesod_vendored_deps
ln -s ../yesod_vendored_deps vendor
```

## Updating the Vendor Cache

If `MODULE.bazel` changes, you may want to update the shared cache. Because `bazel vendor` can fail on complex cross-platform targets (like NVIDIA drivers or private OCI images), we use an **Allowlist Strategy**: we only vendor the "safe" repositories (Go, Python, Starlark) that are useful for reading.

### How to Re-Vendor

1.  **Generate the Clean Repo List:**
    Run the following command to generate a list of all fetchable repositories, filtering out known problem areas (NVIDIA, OCI, etc.):

    ```bash
    bazel mod dump_repo_mapping "" | python3 -c "import json, sys; m = json.load(sys.stdin); print('\n'.join(m.values()))" | grep -vE "nvidia|coder_dev_base_image|distroless|noble|gevent|triton|audioop|mappings_test_external_repo|^$" > clean_repo_list.txt
    ```

2.  **Run Bazel Vendor:**
    Execute the vendor command targeting *only* the clean list. We perform this step in a temporary directory or the main worktree, then move the result to the shared location.

    ```bash
    # 1. Run vendor command
    cat clean_repo_list.txt | xargs -I {} echo "--repo=@@{}" | xargs bazel vendor --vendor_dir=vendor

    # 2. Move to shared location (if updating)
    # BE CAREFUL: this replaces the existing cache
    rm -rf ../yesod_vendored_deps
    mv vendor ../yesod_vendored_deps
    
    # 3. Restore local symlink
    ln -s ../yesod_vendored_deps vendor
    ```