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feat: Use full flamegraph for metrickit app hangs
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+297
-23
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6 files changed

+297
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‎CHANGELOG.md‎

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Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
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- Add package traits for UI framework opt-out (#7578).
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When building from source with Swift 6.1+ (using `Package@swift-6.1.swift`), you can enable the `NoUIFramework` trait to avoid linking UIKit or AppKit. Use this for command-line tools, headless server contexts, or other environments where UI frameworks are unavailable.
99
In Xcode 26.4 and later, add the Sentry package as a dependency and the `SentrySPM` product, then enable the `NoUIFramework` trait on the package reference (Package Dependencies → select Sentry → Traits).
10+
- Metric kit app hangs now report a full flamegraph rather than just one stacktrace during the hang. (#7185)
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### Fixes
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‎Sources/Sentry/Public/SentryFrame.h‎

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Original file line numberDiff line numberDiff line change
@@ -70,6 +70,13 @@ NS_SWIFT_NAME(Frame)
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*/
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@property (nonatomic, copy) NSString *_Nullable contextLine;
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/**
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* Index of the parent frame used for flamegraphs.
75+
*/
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@property (nonatomic, copy) NSNumber *_Nullable parentIndex;
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@property (nonatomic, copy) NSNumber *_Nullable sampleCount;
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/**
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* Source code lines before the error location (up to 5 lines).
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* Mostly used for Godot errors.

‎Sources/Sentry/SentryFrame.m‎

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@@ -28,6 +28,8 @@ - (instancetype)init
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[serializedData setValue:self.platform forKey:@"platform"];
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[serializedData setValue:self.contextLine forKey:@"context_line"];
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[serializedData setValue:self.preContext forKey:@"pre_context"];
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[serializedData setValue:self.parentIndex forKey:@"parent_index"];
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[serializedData setValue:self.sampleCount forKey:@"sample_count"];
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[serializedData setValue:self.postContext forKey:@"post_context"];
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[serializedData setValue:sentry_sanitize(self.vars) forKey:@"vars"];
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[SentryDictionary setBoolValue:self.inApp forKey:@"in_app" intoDictionary:serializedData];

‎Sources/Swift/Core/MetricKit/SentryMXCallStackTree+Parsing.swift‎

Lines changed: 52 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -8,22 +8,7 @@ extension SentryMXCallStackTree {
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frame.toDebugMeta()
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}.unique { $0.debugID }
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}
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func prepare(event: Event, inAppLogic: SentryInAppLogic?, handled: Bool) {
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let debugMeta = toDebugMeta()
14-
let threads = sentryMXBacktrace(inAppLogic: inAppLogic, handled: handled)
15-
// First look for the crashing thread, but for events that were not a crash (like a hang) take the first thread
16-
// since those events only report one thread
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let exceptionThread = threads.first { $0.crashed?.boolValue == true } ?? threads.first
18-
event.debugMeta = debugMeta
19-
event.threads = threads
20-
21-
if let exceptionThread, let exception = event.exceptions?[0] {
22-
exception.stacktrace = exceptionThread.stacktrace
23-
exception.threadId = exceptionThread.threadId
24-
}
25-
}
26-
11+
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// A MetricKit CallStackTree is a flamegraph, but many Sentry APIs only support
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// a thread backtrace. A flamegraph is just a collection of many thread backtraces
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// generated by taking multiple samples. For example a hang from metric kit will
@@ -66,6 +51,40 @@ extension SentryMXCallStackTree {
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return thread
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}
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}
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/// Flattens the call stack tree into a single thread with all frames.
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/// Each frame includes metadata in its `vars` field to allow reconstructing the original tree:
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/// - `parent_frame_index`: The index of the parent frame in the flat list (-1 for root frames)
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/// - `sample_count`: The number of samples at this frame
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///
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/// This preserves all sample data from the flamegraph rather than just the most common stack.
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func flattenedBacktrace(inAppLogic: SentryInAppLogic?, handled: Bool) -> [SentryThread] {
62+
callStacks.enumerated().map { index, callStack in
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let thread = SentryThread(threadId: NSNumber(value: index))
64+
var frames: [Frame] = []
65+
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// Traverse the tree and flatten all frames with parent references
67+
for rootFrame in callStack.callStackRootFrames {
68+
flattenFrame(rootFrame, parentIndex: -1, frames: &frames, inAppLogic: inAppLogic)
69+
}
70+
71+
thread.stacktrace = SentryStacktrace(frames: frames, registers: [:])
72+
thread.crashed = NSNumber(value: (callStack.threadAttributed ?? false) && !handled)
73+
return thread
74+
}
75+
}
76+
77+
private func flattenFrame(_ mxFrame: SentryMXFrame, parentIndex: Int, frames: inout [Frame], inAppLogic: SentryInAppLogic?) {
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let currentIndex = frames.count
79+
let frame = mxFrame.toSentryFrameWithTreeData(frameIndex: currentIndex, parentFrameIndex: parentIndex)
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frame.inApp = NSNumber(value: inAppLogic?.is(inApp: frame.package) ?? false)
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frames.append(frame)
82+
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// Recursively process child frames
84+
for subFrame in mxFrame.subFrames ?? [] {
85+
flattenFrame(subFrame, parentIndex: currentIndex, frames: &frames, inAppLogic: inAppLogic)
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}
87+
}
6988
}
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7190
extension SentryMXCallStack {
@@ -87,7 +106,7 @@ extension SentryMXFrame {
87106
}
88107
return [result] + (subFrames?.flatMap { $0.toDebugMeta() } ?? [])
89108
}
90-
109+
91110
func toSamples() -> [MXSample] {
92111
let selfFrame = MXSample.MXFrame(binaryUUID: binaryUUID, offsetIntoBinaryTextSegment: offsetIntoBinaryTextSegment, binaryName: binaryName, address: address)
93112
let subframes = subFrames ?? []
@@ -100,6 +119,22 @@ extension SentryMXFrame {
100119
}
101120
return result
102121
}
122+
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/// Converts this frame to a SentryFrame with tree metadata in the `vars` field.
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/// The metadata allows reconstructing the original tree structure from a flat list.
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func toSentryFrameWithTreeData(frameIndex: Int, parentFrameIndex: Int) -> Frame {
126+
let frame = Frame()
127+
frame.package = binaryName
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frame.instructionAddress = sentry_formatHexAddressUInt64Swift(address)
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if offsetIntoBinaryTextSegment >= 0 && offsetIntoBinaryTextSegment < address {
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frame.imageAddress = sentry_formatHexAddressUInt64Swift(address - UInt64(offsetIntoBinaryTextSegment))
131+
}
132+
133+
frame.parentIndex = parentFrameIndex as NSNumber
134+
frame.sampleCount = sampleCount as NSNumber?
135+
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return frame
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}
103138
}
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105140
private extension MXSample.MXFrame {

‎Sources/Swift/Core/MetricKit/SentryMXManager.swift‎

Lines changed: 22 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -80,12 +80,12 @@ final class SentryMXManager: NSObject, MXMetricManagerSubscriber {
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payload.hangDiagnostics?.forEach { diagnostic in
8181
let hangDuration = measurementFormatter.string(from: diagnostic.hangDuration)
8282
let exceptionValue = "MXHangDiagnostic hangDuration:\(hangDuration)"
83-
captureEvent(handled: true, exceptionValue: exceptionValue, exceptionType: "MXHangDiagnostic", exceptionMechanism: hangDiagnosticMechanism, timeStampBegin: payload.timeStampBegin, diagnostic: diagnostic)
83+
captureEvent(handled: true, exceptionValue: exceptionValue, exceptionType: "MXHangDiagnostic", exceptionMechanism: hangDiagnosticMechanism, timeStampBegin: payload.timeStampBegin, diagnostic: diagnostic, useFullCallStackTree: true)
8484
}
8585
}
8686
}
8787

88-
func captureEvent(handled: Bool, exceptionValue: String, exceptionType: String, exceptionMechanism: String, timeStampBegin: Date, diagnostic: MXDiagnostic & CallStackTreeProviding) {
88+
func captureEvent(handled: Bool, exceptionValue: String, exceptionType: String, exceptionMechanism: String, timeStampBegin: Date, diagnostic: MXDiagnostic & CallStackTreeProviding, useFullCallStackTree: Bool = false) {
8989
if let callStackTree = try? SentryMXCallStackTree.from(data: diagnostic.callStackTree.jsonRepresentation()) {
9090
let event = Event(level: handled ? .warning : .error)
9191
event.timestamp = timeStampBegin
@@ -95,12 +95,29 @@ final class SentryMXManager: NSObject, MXMetricManagerSubscriber {
9595
mechanism.synthetic = true
9696
exception.mechanism = mechanism
9797
event.exceptions = [exception]
98-
capture(event: event, handled: handled, callStackTree: callStackTree, diagnosticJSON: diagnostic.jsonRepresentation())
98+
capture(event: event, handled: handled, callStackTree: callStackTree, diagnosticJSON: diagnostic.jsonRepresentation(), useFullCallStackTree: useFullCallStackTree)
9999
}
100100
}
101101

102-
func capture(event: Event, handled: Bool, callStackTree: SentryMXCallStackTree, diagnosticJSON: Data) {
103-
callStackTree.prepare(event: event, inAppLogic: inAppLogic, handled: handled)
102+
func capture(event: Event, handled: Bool, callStackTree: SentryMXCallStackTree, diagnosticJSON: Data, useFullCallStackTree: Bool = false) {
103+
let debugMeta = callStackTree.toDebugMeta()
104+
let threads: [SentryThread]
105+
if useFullCallStackTree {
106+
// For hang diagnostics, use the flattened tree to preserve all samples
107+
threads = callStackTree.flattenedBacktrace(inAppLogic: inAppLogic, handled: handled)
108+
} else {
109+
threads = callStackTree.sentryMXBacktrace(inAppLogic: inAppLogic, handled: handled)
110+
}
111+
// First look for the crashing thread, but for events that were not a crash (like a hang) take the first thread
112+
// since those events only report one thread
113+
let exceptionThread = threads.first { $0.crashed?.boolValue == true } ?? threads.first
114+
event.debugMeta = debugMeta
115+
event.threads = threads
116+
117+
if let exceptionThread, let exception = event.exceptions?[0] {
118+
exception.stacktrace = exceptionThread.stacktrace
119+
exception.threadId = exceptionThread.threadId
120+
}
104121
// The crash event can be way from the past. We don't want to impact the current session.
105122
// Therefore we don't call captureFatalEvent.
106123
capture(event: event, diagnosticJSON: diagnosticJSON)

‎sdk_api.json‎

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Original file line numberDiff line numberDiff line change
@@ -13505,10 +13505,222 @@
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},
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{
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"accessors": [
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"name": "parentIndex",
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"printedName": "parentIndex",
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"children": [
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{
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"accessorKind": "get",
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"kind": "TypeNominal",
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"name": "Optional",
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"printedName": "Foundation.NSNumber?",
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"children": [
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{
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"kind": "TypeNominal",
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"name": "NSNumber",
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"printedName": "Foundation.NSNumber",
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"usr": "c:objc(cs)NSNumber"
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}
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],
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"usr": "s:Sq"
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}
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],
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"declKind": "Var",
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"usr": "c:objc(cs)SentryFrame(py)parentIndex",
13528+
"moduleName": "Sentry",
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"isOpen": true,
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"objc_name": "parentIndex",
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"declAttributes": [
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"NSCopying",
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"ObjC",
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"Dynamic"
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],
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"accessors": [
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{
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"kind": "Accessor",
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"name": "Get",
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"printedName": "Get()",
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"children": [
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{
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"kind": "TypeNominal",
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"name": "Optional",
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"printedName": "Foundation.NSNumber?",
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"children": [
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{
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"kind": "TypeNominal",
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"name": "NSNumber",
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"printedName": "Foundation.NSNumber",
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"usr": "c:objc(cs)NSNumber"
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}
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],
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"usr": "s:Sq"
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}
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],
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"declKind": "Accessor",
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"usr": "c:objc(cs)SentryFrame(im)parentIndex",
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"moduleName": "Sentry",
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"isOpen": true,
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"objc_name": "parentIndex",
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"declAttributes": [
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"DiscardableResult",
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"ObjC",
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"Dynamic"
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],
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"accessorKind": "get"
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},
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{
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"kind": "Accessor",
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"name": "Set",
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"printedName": "Set()",
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"children": [
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{
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"kind": "TypeNameAlias",
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"name": "Void",
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"printedName": "Swift.Void",
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"children": [
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{
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"kind": "TypeNominal",
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"name": "Void",
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"printedName": "()"
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}
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]
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},
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{
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"kind": "TypeNominal",
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"name": "Optional",
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"printedName": "Foundation.NSNumber?",
13590+
"children": [
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{
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"kind": "TypeNominal",
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"name": "NSNumber",
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"printedName": "Foundation.NSNumber",
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"usr": "c:objc(cs)NSNumber"
13596+
}
13597+
],
13598+
"usr": "s:Sq"
13599+
}
13600+
],
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"declKind": "Accessor",
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"usr": "c:objc(cs)SentryFrame(im)setParentIndex:",
13603+
"moduleName": "Sentry",
13604+
"isOpen": true,
13605+
"objc_name": "setParentIndex:",
13606+
"declAttributes": [
13607+
"ObjC",
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"Dynamic"
13609+
],
13610+
"accessorKind": "set"
13611+
}
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]
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},
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{
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"kind": "Var",
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"name": "sampleCount",
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"printedName": "sampleCount",
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"children": [
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{
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"kind": "TypeNominal",
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"name": "Optional",
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"printedName": "Foundation.NSNumber?",
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"children": [
13624+
{
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"kind": "TypeNominal",
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"name": "NSNumber",
13627+
"printedName": "Foundation.NSNumber",
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"usr": "c:objc(cs)NSNumber"
13629+
}
13630+
],
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"usr": "s:Sq"
13632+
}
13633+
],
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"declKind": "Var",
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"usr": "c:objc(cs)SentryFrame(py)sampleCount",
13636+
"moduleName": "Sentry",
13637+
"isOpen": true,
13638+
"objc_name": "sampleCount",
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"declAttributes": [
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"NSCopying",
13641+
"ObjC",
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"Dynamic"
13643+
],
13644+
"accessors": [
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{
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"kind": "Accessor",
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"name": "Get",
13648+
"printedName": "Get()",
1351013649
"children": [
1351113650
{
13651+
"kind": "TypeNominal",
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"name": "Optional",
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"printedName": "Foundation.NSNumber?",
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"children": [
13655+
{
13656+
"kind": "TypeNominal",
13657+
"name": "NSNumber",
13658+
"printedName": "Foundation.NSNumber",
13659+
"usr": "c:objc(cs)NSNumber"
13660+
}
13661+
],
13662+
"usr": "s:Sq"
13663+
}
13664+
],
13665+
"declKind": "Accessor",
13666+
"usr": "c:objc(cs)SentryFrame(im)sampleCount",
13667+
"moduleName": "Sentry",
13668+
"isOpen": true,
13669+
"objc_name": "sampleCount",
13670+
"declAttributes": [
13671+
"DiscardableResult",
13672+
"ObjC",
13673+
"Dynamic"
13674+
],
13675+
"accessorKind": "get"
13676+
},
13677+
{
13678+
"kind": "Accessor",
13679+
"name": "Set",
13680+
"printedName": "Set()",
13681+
"children": [
13682+
{
13683+
"kind": "TypeNameAlias",
13684+
"name": "Void",
13685+
"printedName": "Swift.Void",
13686+
"children": [
13687+
{
13688+
"kind": "TypeNominal",
13689+
"name": "Void",
13690+
"printedName": "()"
13691+
}
13692+
]
13693+
},
13694+
{
13695+
"kind": "TypeNominal",
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"name": "Optional",
13697+
"printedName": "Foundation.NSNumber?",
13698+
"children": [
13699+
{
13700+
"kind": "TypeNominal",
13701+
"name": "NSNumber",
13702+
"printedName": "Foundation.NSNumber",
13703+
"usr": "c:objc(cs)NSNumber"
13704+
}
13705+
],
13706+
"usr": "s:Sq"
13707+
}
13708+
],
13709+
"declKind": "Accessor",
13710+
"usr": "c:objc(cs)SentryFrame(im)setSampleCount:",
13711+
"moduleName": "Sentry",
13712+
"isOpen": true,
13713+
"objc_name": "setSampleCount:",
13714+
"declAttributes": [
13715+
"ObjC",
13716+
"Dynamic"
13717+
],
13718+
"accessorKind": "set"
13719+
}
13720+
]
13721+
},
13722+
{
13723+
"kind": "Var",
1351213724
"children": [
1351313725
{
1351413726
"kind": "TypeNominal",

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