Fix perception checking in computed property with geometry reader. (pointfreeco#45)

* Fix perception checking in computed property with geometry reader.

* Update messaging

Author: mbrandonw

Sources/Perception/Bindable.swift

@@ -5,11 +5,11 @@
   /// perceptible objects.
   ///
   /// A backport of SwiftUI's `Bindable` property wrapper.
-  @available(iOS, introduced: 13, obsoleted: 17)
-  @available(macOS, introduced: 10.15, obsoleted: 14)
-  @available(tvOS, introduced: 13, obsoleted: 17)
-  @available(watchOS, introduced: 6, obsoleted: 10)
-  @available(visionOS, unavailable)
+  @available(iOS, introduced: 13, obsoleted: 17, message: "Use @Bindable without the 'Perception.' prefix.")
+  @available(macOS, introduced: 10.15, obsoleted: 14, message: "Use @Bindable without the 'Perception.' prefix.")
+  @available(tvOS, introduced: 13, obsoleted: 17, message: "Use @Bindable without the 'Perception.' prefix.")
+  @available(watchOS, introduced: 6, obsoleted: 10, message: "Use @Bindable without the 'Perception.' prefix.")
+  @available(visionOS, unavailable, message: "Use @Bindable without the 'Perception.' prefix.")
   @dynamicMemberLookup
   @propertyWrapper
   public struct Bindable<Value> {

Sources/Perception/PerceptionRegistrar.swift

@@ -1,4 +1,5 @@
 import Foundation
+import SwiftUI
 
 #if canImport(Observation)
   import Observation
@@ -230,10 +231,15 @@ extension PerceptionRegistrar: Hashable {
           let mangledSymbol = callStackSymbol.utf8
             .drop(while: { $0 != .init(ascii: "$") })
             .prefix(while: { $0 != .init(ascii: " ") })
-
+          guard let demangled = String(Substring(mangledSymbol)).demangled
+          else {
+            continue
+          }
+          if demangled.isGeometryTrailingClosure {
+            return true
+          }
           guard
             mangledSymbol.isMangledViewBodyGetter,
-            let demangled = String(Substring(mangledSymbol)).demangled,
             !demangled.isSuspendingClosure,
             !demangled.isActionClosure
           else {
@@ -247,7 +253,12 @@ extension PerceptionRegistrar: Hashable {
     }
   }
 
+
   extension String {
+    var isGeometryTrailingClosure: Bool {
+      self.contains("(SwiftUI.GeometryProxy) -> ")
+    }
+
     fileprivate var isSuspendingClosure: Bool {
       let fragment = self.utf8.drop(while: { $0 != .init(ascii: ")") }).dropFirst()
       return fragment.starts(

Tests/PerceptionTests/RuntimeWarningTests.swift

@@ -499,6 +499,51 @@
       try await Task.sleep(for: .milliseconds(100))
     }
 
+    func testGeometryReader_WithoutPerceptionTracking() {
+      struct FeatureView: View {
+        let model = Model()
+        var body: some View {
+          WithPerceptionTracking {
+            GeometryReader { _ in
+              Text(expectRuntimeWarning { self.model.count }.description)
+            }
+          }
+        }
+      }
+      self.render(FeatureView())
+    }
+
+    func testGeometryReader_WithProperPerceptionTracking() {
+      struct FeatureView: View {
+        let model = Model()
+        var body: some View {
+          GeometryReader { _ in
+            WithPerceptionTracking {
+              Text(self.model.count.description)
+            }
+          }
+        }
+      }
+      self.render(FeatureView())
+    }
+
+    func testGeometryReader_ComputedProperty_ImproperPerceptionTracking() {
+      struct FeatureView: View {
+        let model = Model()
+        var body: some View {
+          WithPerceptionTracking {
+            content
+          }
+        }
+        var content: some View {
+          GeometryReader { _ in
+            Text(expectRuntimeWarning { self.model.count }.description)
+          }
+        }
+      }
+      self.render(FeatureView())
+    }
+
     private func render(_ view: some View) {
       let image = ImageRenderer(content: view).cgImage
       _ = image