warp/WARP.md

WARP.md

This file provides guidance when working with code in this repository.

Development Commands

Build and Run

• cargo run - Build and run Warp locally
• cargo bundle --bin warp - Bundle the main app

Running with local warp-server

To connect Warp client to a local warp-server instance:

# Connect to server on default port 8080
cargo run --features with_local_server

# Connect to server on custom port (e.g., 8082)
SERVER_ROOT_URL=http://localhost:8082 WS_SERVER_URL=ws://localhost:8082/graphql/v2 cargo run --features with_local_server

Environment variables:

• SERVER_ROOT_URL - HTTP endpoint (default: http://localhost:8080)
• WS_SERVER_URL - WebSocket endpoint (default: ws://localhost:8080/graphql/v2)

Testing

• cargo nextest run --no-fail-fast --workspace --exclude command-signatures-v2 - Run tests with nextest
• cargo nextest run -p warp_completer --features v2 - Run completer tests with v2 features
• cargo test --doc - Run doc tests
• cargo test - Run standard tests for individual packages

Linting and Formatting

• ./script/presubmit - Run all presubmit checks (fmt, clippy, tests)
• cargo fmt - Format code
• cargo clippy --workspace --all-targets --all-features --tests -- -D warnings - Run clippy
• ./script/run-clang-format.py -r --extensions 'c,h,cpp,m' ./crates/warpui/src/ ./app/src/ - Format C/C++/Obj-C code
• find . -name "*.wgsl" -exec wgslfmt --check {} + - Check WGSL shader formatting

Platform Setup

• ./script/bootstrap - Platform-specific setup (calls platform-specific bootstrap scripts)
• ./script/install_cargo_build_deps - Install Cargo build dependencies
• ./script/install_cargo_test_deps - Install Cargo test dependencies

Architecture Overview

This is a Rust-based terminal emulator with a custom UI framework called WarpUI.

Key Components

WarpUI Framework (ui/):

• Custom UI framework with Entity-Component-Handle pattern
• Global App object owns all views/models (entities)
• Views hold ViewHandle<T> references to other views
• AppContext provides temporary access to handles during render/events
• Elements describe visual layout (Flutter-inspired)
• Actions system for event handling
• MouseStateHandle must be created once during construction, and then referenced/cloned anywhere we're using mouse input to track mouse changes. Inline MouseStateHandle::default() while rendering will cause no mouse interactions to work.

Main App (app/):

• Terminal emulation and shell management (terminal/)
• AI integration including Agent Mode (ai/)
• Cloud synchronization and Drive features (drive/)
• Authentication and user management (auth/)
• Settings and preferences (settings/)
• Workspace and session management (workspace/)

Core Libraries:

• crates/warp_core/ - Core utilities and platform abstractions
• crates/editor/ - Text editing functionality
• crates/warpui/ and crates/warpui_core/ - Custom UI framework
• crates/ipc/ - Inter-process communication
• crates/graphql/ - GraphQL client and schema

Key Architectural Patterns

1. Entity-Handle System: Views reference other views via handles, not direct ownership
2. Modular Structure: Workspace contains multiple workspace configurations, each with terminals, notebooks, etc.
3. Cross-Platform: Native implementations for macOS, Windows, Linux, plus WASM target
4. AI Integration: Built-in AI assistant with context awareness and codebase indexing
5. Cloud Sync: Objects can be synchronized across devices via Warp Drive

Development Guidelines

Workspace Structure:

• This is a Cargo workspace with 60+ member crates
• Main binary is in app/, UI framework in crates/warpui/
• Platform-specific code is conditionally compiled
• Integration tests are in crates/integration/

Coding Style Preferences:

• Avoid unnecessary type annotations, especially in closure params.
• Avoid using too many Rust path qualifiers and use imports for concision. Place import statements at the top of the file as per convention. An exception to this is inside cfg-guarded code branches. In those cases, you can either embed the import into the relevant scope or just use an absolute path for one-offs.
• If a function takes a context parameter (AppContext, ViewContext, or ModelContext), it should be named ctx and go last. The one exception is for functions that take a closure parameter, in which case the closure should be last.
• Always remove unused parameters completely rather than prefixing them with _. Update the function signature and all call sites accordingly.
• Prefer inline format arguments in macros like println!, eprintln!, and format! (for example, eprintln!("{message}") instead of eprintln!("{}", message)) to satisfy Clippy's uninlined_format_args lint.
• Do not remove existing comments when making unrelated changes. Only remove or modify a comment if the logic it describes has changed.

Terminal Model Locking:

• Be extremely careful when calling model.lock() on the terminal model (TerminalModel). Acquiring multiple locks on the same model from different call sites can cause a deadlock, resulting in a UI freeze (beach ball on macOS).
• Before adding a new model.lock() call, verify that no caller in the current call stack already holds the lock.
• Prefer passing already-locked model references down the call stack rather than acquiring new locks.
• If you must lock the model, keep the lock scope as short as possible and avoid calling other functions that might also attempt to lock.

Testing:

• Use cargo nextest for parallel test execution
• Integration tests use custom framework in integration/
• Tests should be run via presubmit script before submitting
• Unit tests should be placed in separate files using the naming convention ${filename}_tests.rs or mod_test.rs
• Test files should be included at the end of their corresponding module with:

  #[cfg(test)]
  #[path = "filename_tests.rs"]  // or "mod_test.rs"
  mod tests;
  

Pull Request Workflow:

• ALWAYS run cargo fmt and cargo clippy (the versions specified in ./script/presubmit) before opening a PR or pushing updates to an existing PR branch
• Those commands must pass completely before creating or updating a pull request
• Specifically, ensure cargo fmt and cargo clippy checks pass
• If they fail, fix all issues before proceeding with the PR
• This applies to:
  • Opening new pull requests
  • Pushing new commits to existing PR branches
  • Any branch updates that will be reviewed
• When opening PRs, use the PR template at .github/pull_request_template.md
• Add changelog entries when appropriate using the format at the bottom of the PR template. Use the following prefixes (without the {{}} brackets):
  • CHANGELOG-NEW-FEATURE: for new, relatively sizable features (use sparingly - these may get marketing/docs)
  • CHANGELOG-IMPROVEMENT: for new functionality of existing features
  • CHANGELOG-BUG-FIX: for fixes related to known bugs or regressions
  • CHANGELOG-IMAGE: for GCP-hosted image URLs
  • Leave changelog lines blank or remove them if no changelog entry is needed

Database:

• Uses Diesel ORM with SQLite
• Migrations in crates/persistence/migrations/
• Schema defined in crates/persistence/src/schema.rs

GraphQL:

• Schema and client code generation from crates/warp_graphql_schema/api/schema.graphql
• TypeScript types generated for frontend integration

Feature Flags

Warp uses compile-time feature flags with a small runtime plumbing layer.

How to add a feature flag:

• Add a new variant to warp_core/src/features.rs in the FeatureFlag enum
• (Optional) Enable it by default for dogfood builds by listing it in DOGFOOD_FLAGS
• Gate code paths with FeatureFlag::YourFlag.is_enabled()
• For preview or release rollout, add to PREVIEW_FLAGS or RELEASE_FLAGS respectively (as appropriate)

Best practices:

• Prefer runtime checks over cfg directives: Prefer FeatureFlag::YourFlag.is_enabled() over #[cfg(...)] compile-time directives so flags can be toggled without recompilation and are easier to clean up later. Use #[cfg(...)] only when the code cannot compile without them (for example, platform-specific code or dependencies that do not exist when the feature is disabled).
• Keep flags high-level and product-focused rather than per-call-site
• Remove the flag and dead branches after launch has stabilized
• For UI sections that expose a new feature, hide the UI behind the same flag

Example:

#[derive(Sequence)]
pub enum FeatureFlag {
    YourNewFeature,
}

// Default-on for dogfood builds
pub const DOGFOOD_FLAGS: &[FeatureFlag] = &[
    FeatureFlag::YourNewFeature,
];

// Use in code
if FeatureFlag::YourNewFeature.is_enabled() {
    // gated behavior
}

Exhaustive Matching

When adding/editing match statements, avoid using the wildcard _ when at all possible. Exhaustive matching is helpful for ensuring that all variants are handled, especially when adding new variants to enums in the future.