I'm seeing a regression in SwiftUI Charts on iOS 27 beta 1. Any view placed inside a BarMark's overlay annotation no longer receives the size of the parent BarMark. It collapses to zero, so any content sized from geo.size (e.g. a Rectangle meant to fill the bar) renders empty or incorrectly.
Expected: The GeometryReader reports the BarMark's rendered width/height, and the Rectangle fills the BarMark (this is the behavior in iOS 26 and earlier).
Actual: On iOS 27 beta 1, geo.size is effectively zero, so the overlay content has an extremely small size.
I suspect this could be a small bug with the new ContentBuilder / ViewBuilder changes but that's just a hunch.
Here's a code sample which reproduces the issue.
// MARK: - Mock Data Models
struct ScheduleSeries: Identifiable {
let id = UUID()
let data: [ScheduleItem]
}
struct ScheduleItem: Identifiable {
let id = UUID()
let startDate: Date
let startHour: Double
let endHour: Double
let secondaryText: String?
}
// MARK: - Minimal Reproducible Example
struct ContentView: View {
// Generate two consecutive days for the mock data
let mockSchedule: [ScheduleSeries] = [
ScheduleSeries(data: [
ScheduleItem(
startDate: Date(),
startHour: 9.0,
endHour: 11.5,
secondaryText: "Morning Event"
),
ScheduleItem(
startDate: Calendar.current.date(byAdding: .day, value: 1, to: Date())!,
startHour: 13.0,
endHour: 16.0,
secondaryText: "Afternoon Event"
)
])
]
var body: some View {
VStack(alignment: .leading) {
Text("FB: Annotation Sizing Bug")
.font(.headline)
.padding(.bottom, 8)
Text("Expected: The gray Rectangle should stretch to fill the BarMark.\nActual: GeometryReader/Annotation fails to size to the parent BarMark.")
.font(.caption)
.foregroundColor(.secondary)
.padding(.bottom)
Chart(mockSchedule) { series in
ForEach(series.data, id: \.startDate) { element in
BarMark(
x: .value("Day", element.startDate, unit: .day, calendar: .current),
yStart: .value("Start", element.startHour),
yEnd: .value("End", element.endHour),
width: .ratio(0.99)
)
.annotation(position: .overlay, alignment: .topLeading) { item in
ZStack {
VStack(alignment: .leading, spacing: 0) {
// BUG DEMONSTRATION:
// This GeometryReader and Rectangle previously filled the BarMark, but in Xcode 27 it does not
GeometryReader { geo in
Rectangle()
.fill(Color.black.opacity(0.15))
.frame(width: geo.size.width, height: geo.size.height)
}
}
.foregroundColor(.white)
.font(.caption2)
}
}
}
}
.chartYScale(domain: 0...24) // Lock the Y-axis to a 24-hour scale
}
.padding()
}
}
Environment:
Xcode 27 beta 1 / iOS 27 beta 1
Reproduces on device and Simulator
Worked as expected on iOS 26 and earlier
Here's what the issue looks like in our app with zero code changes:
iOS 26
iOS 27
I've filed a feedback report (FB23016343) with a sample project attached.
Has anyone else hit this, or found a workaround for sizing overlay annotation content to a BarMark in iOS 27? Thanks!