swift-composable-architecture-mirror/Sources/ComposableArchitecture/Internal/RuntimeWarnings.swift

#if DEBUG
  import os
  import XCTestDynamicOverlay

  // NB: Xcode runtime warnings offer a much better experience than traditional assertions and
  //     breakpoints, but Apple provides no means of creating custom runtime warnings ourselves.
  //     To work around this, we hook into SwiftUI's runtime issue delivery mechanism, instead.
  //
  // Feedback filed: https://gist.github.com/stephencelis/a8d06383ed6ccde3e5ef5d1b3ad52bbc
  private let rw = (
    dso: { () -> UnsafeMutableRawPointer in
      let count = _dyld_image_count()
      for i in 0..<count {
        if let name = _dyld_get_image_name(i) {
          let swiftString = String(cString: name)
          if swiftString.hasSuffix("/SwiftUI") {
            if let header = _dyld_get_image_header(i) {
              return UnsafeMutableRawPointer(mutating: UnsafeRawPointer(header))
            }
          }
        }
      }
      return UnsafeMutableRawPointer(mutating: #dsohandle)
    }(),
    log: OSLog(subsystem: "com.apple.runtime-issues", category: "ComposableArchitecture")
  )
#endif

@_transparent
@inline(__always)
func runtimeWarning(
  _ message: @autoclosure () -> StaticString,
  _ args: @autoclosure () -> [CVarArg] = []
) {
  #if DEBUG
    let message = message()
    unsafeBitCast(
      os_log as (OSLogType, UnsafeRawPointer, OSLog, StaticString, CVarArg...) -> Void,
      to: ((OSLogType, UnsafeRawPointer, OSLog, StaticString, [CVarArg]) -> Void).self
    )(.fault, rw.dso, rw.log, message, args())
    XCTFail(String(format: "\(message)", arguments: args()))
  #endif
}