# Patching Dependencies > Patches Cargo dependencies to use local checkouts or different branches. Use when testing changes across multiple repositories, debugging dependency issues, or developing against local polkadot-sdk/frontier/moonkit forks. Use when this capability is needed. - Skill: `tomevault-io/patching-dependencies` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/patching-dependencies` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/patching-dependencies/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/patching-dependencies --- # Patching Dependencies ## Contents - [Overview](#overview) - [Using Diener](#using-diener) - [Manual Patching](#manual-patching) - [Common Scenarios](#common-scenarios) - [Reverting Patches](#reverting-patches) ## Overview Moonbeam depends on multiple external repositories that must stay in sync. These are typically available in the parent workspace directory (`../`): | Repository | Path | Purpose | |----------------|-------------------|------------------------------------------------------------| | `polkadot-sdk` | `../polkadot-sdk` | Substrate/Polkadot core framework | | `frontier` | `../frontier` | Ethereum compatibility layer (pallet-evm, pallet-ethereum) | | `moonkit` | `../moonkit` | Moonbeam-specific pallets and primitives | | `evm` | `../evm` | Low-level EVM implementation | | `ethereum` | `../ethereum` | Ethereum types and primitives | When developing features that span multiple repositories, you need to patch dependencies to point to local checkouts or different branches. ## Using Diener Diener is Parity's tool for managing Polkadot SDK dependencies. ### Installation ```bash # Install from git (recommended - crates.io version is outdated) cargo install --git https://github.com/paritytech/diener # Or from crates.io (may not support latest Rust editions) cargo install diener ``` ### Patch to Local Checkout Redirect all polkadot-sdk dependencies to a local path: ```bash # Patch polkadot-sdk dependencies to local checkout diener patch --crates-to-patch ../polkadot-sdk --target Cargo.toml ``` This adds `[patch]` sections to the workspace `Cargo.toml` for each crate found in the local checkout. ### Update Branch/Tag Change all dependencies to point to a different branch: ```bash # Update to a specific branch diener update --branch moonbeam-polkadot-stable2506 # Update to a specific tag diener update --tag polkadot-stable2407 # Update to a specific commit diener update --rev abc123def ``` ## Manual Patching For finer control, add patch sections manually to `Cargo.toml`: ### Patch to Local Path ```toml [patch."https://github.com/moonbeam-foundation/polkadot-sdk"] # Patch specific crates to local paths frame-support = { path = "../polkadot-sdk/substrate/frame/support" } sp-runtime = { path = "../polkadot-sdk/substrate/primitives/runtime" } ``` ### Patch to Different Git Source ```toml [patch."https://github.com/moonbeam-foundation/polkadot-sdk"] # Patch to a different branch frame-support = { git = "https://github.com/moonbeam-foundation/polkadot-sdk", branch = "my-feature-branch" } # Patch to a specific commit sp-runtime = { git = "https://github.com/moonbeam-foundation/polkadot-sdk", rev = "abc123" } ``` ### Patch Frontier ```toml [patch."https://github.com/moonbeam-foundation/frontier"] fp-evm = { path = "../frontier/primitives/evm" } pallet-evm = { path = "../frontier/frame/evm" } ``` ### Patch Moonkit ```toml [patch."https://github.com/moonbeam-foundation/moonkit"] nimbus-primitives = { path = "../moonkit/primitives/nimbus-primitives" } pallet-author-inherent = { path = "../moonkit/pallets/author-inherent" } ``` ## Common Scenarios ### Testing polkadot-sdk Changes Locally ```bash # 1. Clone polkadot-sdk if not already git clone https://github.com/moonbeam-foundation/polkadot-sdk ../polkadot-sdk cd ../polkadot-sdk git checkout moonbeam-polkadot-stable2506 # 2. Make your changes # ... # 3. Patch moonbeam to use local checkout cd ../moonbeam diener patch --crates-to-patch ../polkadot-sdk --target Cargo.toml # 4. Build and test cargo build --release ``` ### Upgrading polkadot-sdk Version ```bash # 1. Update all dependencies to new branch diener update --branch moonbeam-polkadot-stable2507 # 2. Check for breaking changes cargo check 2>&1 | head -100 # 3. Fix any compilation errors # ... # 4. Run tests cargo test ``` ### Cross-Repository Feature Development When a feature spans moonbeam, frontier, and polkadot-sdk: ```bash # 1. Set up local checkouts git clone https://github.com/moonbeam-foundation/polkadot-sdk ../polkadot-sdk git clone https://github.com/moonbeam-foundation/frontier ../frontier # 2. Create feature branches in each repo cd ../polkadot-sdk && git checkout -b feature/my-feature cd ../frontier && git checkout -b feature/my-feature cd ../moonbeam && git checkout -b feature/my-feature # 3. Patch moonbeam to use local checkouts cat >> Cargo.toml << 'EOF' [patch."https://github.com/moonbeam-foundation/polkadot-sdk"] # Add specific crates you're modifying frame-support = { path = "../polkadot-sdk/substrate/frame/support" } [patch."https://github.com/moonbeam-foundation/frontier"] pallet-evm = { path = "../frontier/frame/evm" } EOF # 4. Develop and test across all repos cargo build --release ``` ### Debugging Dependency Issues When encountering version conflicts: ```bash # 1. Check dependency tree cargo tree -p frame-support # 2. Find duplicate versions cargo tree -d # 3. Identify the source of conflicts cargo tree -i frame-support ``` ## Reverting Patches ### Remove Diener Patches ```bash # Remove all [patch] sections from Cargo.toml # This is manual - diener doesn't have an unpatch command # Option 1: Git restore git checkout Cargo.toml # Option 2: Manual removal # Delete all [patch."..."] sections from Cargo.toml ``` ### Clean Cargo Cache After reverting patches, clean the build: ```bash cargo clean cargo update ``` ## Important Notes 1. **Never commit local path patches** - They won't work in CI or for other developers 2. **Keep dependencies in sync** - All polkadot-sdk crates must point to the same branch/commit 3. **Update Cargo.lock** - After patching, run `cargo update` to refresh the lock file 4. **Check CI compatibility** - Ensure patches use git URLs, not local paths, before pushing ## Common Crate Paths ### Frontier - `../frontier/frame/evm` - pallet-evm - `../frontier/frame/ethereum` - pallet-ethereum - `../frontier/primitives/evm` - fp-evm - `../frontier/primitives/rpc` - fp-rpc - `../frontier/client/rpc` - fc-rpc ### Moonkit - `../moonkit/primitives/nimbus-primitives` - nimbus-primitives - `../moonkit/pallets/author-inherent` - pallet-author-inherent - `../moonkit/pallets/author-slot-filter` - pallet-author-slot-filter ### EVM - `../evm` - evm crate (interpreter, opcodes) ## Dependency Tree Reference ``` moonbeam ├── polkadot-sdk (moonbeam-foundation/polkadot-sdk) ├── moonkit │ ├── polkadot-sdk (moonbeam-foundation/polkadot-sdk) │ ├── evm │ └── frontier ├── evm └── frontier ├── evm └── polkadot-sdk (moonbeam-foundation/polkadot-sdk) ``` All these must point to compatible versions to avoid conflicts. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/manuelmauro) — claim your Tome and manage your conversions.