SwiftReload

This is an experimental project that enables hot reloading of Swift code in SwiftPM based projects.

Platforms

Platform	CI Status	Support Status
macOS		✅
Linux		✅
Windows		🚧

Quick Start

1. Add SwiftReload to your project's dependencies in Package.swift:

dependencies:[.package(url:"https://github.com/ShaftUI/SwiftReload.git", branch:"main")]

2. Add SwiftReload to your target's dependencies:

.executableTarget(
name:"MyApp",
dependencies:["SwiftReload"])

1. Add -enable-private-imports and -enable-implicit-dynamic flag to your target's build settings:

.executableTarget(
name:"MyApp",
dependencies:["SwiftReload"],
swiftSettings:[.unsafeFlags(["-Xfrontend","-enable-private-imports"],.when(configuration:.debug)),.unsafeFlags(["-Xfrontend","-enable-implicit-dynamic"],.when(configuration:.debug)),],
linkerSettings:[.unsafeFlags(["-Xlinker","--export-dynamic"],.when(platforms:[.linux,.android], configuration:.debug)),])

This enables method swizzling, which SwiftReload uses to replace code at runtime.

On Linux, you also need to add the -Xlinker --export-dynamic flag to the linker settings to export all symbols from the executable.

3. Add the following code at the beginning of your main.swift:

import SwiftReload
LocalSwiftReloader().start()

For complete example, see the Sources/SwiftReloadExample directory.

With ShaftUI

The LocalSwiftReloader has a onReload callback that is called when the code reload is triggered. You can call backend.scheduleReassemble in the callback to rebuild the UI.

#if DEBUGimport SwiftReload
LocalSwiftReloader(onReload: backend.scheduleReassemble).start()#endif

How it works

SwiftReload monitors changes to the source files of your project. When a change is detected, it recompiles the updated source files to a dynamic library and loads it into the running process. The dynamic library then replaces the existing code in the process, effectively enabling hot reloading of Swift code.