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Fix Live Activity cooperative-pool starvation deadlock #2465

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Merged
ps2 merged 1 commit into from
Jul 20, 2026
Merged

Fix Live Activity cooperative-pool starvation deadlock #2465

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112 changes: 52 additions & 60 deletions Loop/Managers/Live Activity/LiveActivityManager.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -103,7 +103,7 @@ class LiveActivityManager : LiveActivityManagerProxy {
let statusContext = UserDefaults.appGroup?.statusExtensionContext
let glucoseFormatter = NumberFormatter.glucoseFormatter(for: unit)

let glucoseSamples = self.getGlucoseSample(unit: unit)
let glucoseSamples = await self.getGlucoseSample(unit: unit)
guard let currentGlucose = glucoseSamples.last else {
print("ERROR: No glucose sample found...")
return
Expand All @@ -118,7 +118,7 @@ class LiveActivityManager : LiveActivityManagerProxy {
delta = "\(deltaValue < 0 ? "-" : "+")\(glucoseFormatter.string(from: abs(deltaValue)) ?? "??")"
}

let bottomRow = self.getBottomRow(
let bottomRow = await self.getBottomRow(
currentGlucose: current,
delta: delta,
statusContext: statusContext,
Expand Down Expand Up @@ -308,53 +308,43 @@ class LiveActivityManager : LiveActivityManagerProxy {
}
}

private func getInsulinOnBoard() -> String {
let updateGroup = DispatchGroup()
var iob = "??"

updateGroup.enter()
self.doseStore.insulinOnBoard(at: Date.now) { result in
switch (result) {
case .failure:
break
case .success(let iobValue):
iob = self.iobFormatter.string(from: iobValue.value) ?? "??"
break
private func getInsulinOnBoard() async -> String {
// NOTE: Do NOT bridge async→sync with DispatchGroup.wait(.distantFuture) here.
// update() runs on a Swift Concurrency cooperative-pool thread; blocking that
// thread starves the (core-count-sized) pool and can deadlock the whole
// concurrency runtime under repeated Live Activity updates. Suspend instead.
return await withCheckedContinuation { continuation in
self.doseStore.insulinOnBoard(at: Date.now) { result in
switch (result) {
case .failure:
continuation.resume(returning: "??")
case .success(let iobValue):
continuation.resume(returning: self.iobFormatter.string(from: iobValue.value) ?? "??")
}
}

updateGroup.leave()
}

_ = updateGroup.wait(timeout: .distantFuture)
return iob
}

private func getGlucoseSample(unit: HKUnit) -> [StoredGlucoseSample] {
let updateGroup = DispatchGroup()
var samples: [StoredGlucoseSample] = []

updateGroup.enter()


private func getGlucoseSample(unit: HKUnit) async -> [StoredGlucoseSample] {
// When in spacious mode, we want to show the predictive line
// In compact mode, we only want to show the history
let timeInterval: TimeInterval = self.settings.addPredictiveLine ? .hours(-2) : .hours(-6)
self.glucoseStore.getGlucoseSamples(
start: adjustedChartStart(Date.now.addingTimeInterval(timeInterval)),
end: Date.now
) { result in
switch (result) {
case .failure:
break
case .success(let data):
samples = data
break

// NOTE: See getInsulinOnBoard() — never block the cooperative pool with a
// DispatchGroup.wait here; suspend the async task instead.
return await withCheckedContinuation { continuation in
self.glucoseStore.getGlucoseSamples(
start: adjustedChartStart(Date.now.addingTimeInterval(timeInterval)),
end: Date.now
) { result in
switch (result) {
case .failure:
continuation.resume(returning: [])
case .success(let data):
continuation.resume(returning: data)
}
}

updateGroup.leave()
}

_ = updateGroup.wait(timeout: .distantFuture)
return samples
}

// If the chart start falls past the half-hour mark (HH:31–HH:59), pull it back to HH:30
Expand Down Expand Up @@ -490,43 +480,45 @@ class LiveActivityManager : LiveActivityManagerProxy {
return glucoseRanges
}

private func getBottomRow(currentGlucose: Double, delta: String, statusContext: StatusExtensionContext?, glucoseFormatter: NumberFormatter) -> [BottomRowItem] {
return self.settings.bottomRowConfiguration.map { type in
private func getBottomRow(currentGlucose: Double, delta: String, statusContext: StatusExtensionContext?, glucoseFormatter: NumberFormatter) async -> [BottomRowItem] {
var items: [BottomRowItem] = []
for type in self.settings.bottomRowConfiguration {
switch(type) {
case .iob:
return BottomRowItem.generic(label: type.name(), value: getInsulinOnBoard(), unit: "U")
items.append(BottomRowItem.generic(label: type.name(), value: await getInsulinOnBoard(), unit: "U"))

case .cob:
var cob: String = "0"
if let cobValue = statusContext?.carbsOnBoard {
cob = self.cobFormatter.string(from: cobValue) ?? "??"
}
return BottomRowItem.generic(label: type.name(), value: cob, unit: "g")
items.append(BottomRowItem.generic(label: type.name(), value: cob, unit: "g"))

case .basal:
guard let netBasalContext = statusContext?.netBasal else {
return BottomRowItem.basal(rate: 0, percentage: 0)
items.append(BottomRowItem.basal(rate: 0, percentage: 0))
continue
}
items.append(BottomRowItem.basal(rate: netBasalContext.rate, percentage: netBasalContext.percentage))

return BottomRowItem.basal(rate: netBasalContext.rate, percentage: netBasalContext.percentage)

case .currentBg:
return BottomRowItem.currentBg(label: type.name(), value: "\(glucoseFormatter.string(from: currentGlucose) ?? "??")", trend: statusContext?.glucoseDisplay?.trendType)
items.append(BottomRowItem.currentBg(label: type.name(), value: "\(glucoseFormatter.string(from: currentGlucose) ?? "??")", trend: statusContext?.glucoseDisplay?.trendType))

case .eventualBg:
guard let eventual = statusContext?.predictedGlucose?.values.last else {
return BottomRowItem.generic(label: type.name(), value: "??", unit: "")
items.append(BottomRowItem.generic(label: type.name(), value: "??", unit: ""))
continue
}

return BottomRowItem.generic(label: type.name(), value: glucoseFormatter.string(from: eventual) ?? "??", unit: "")

items.append(BottomRowItem.generic(label: type.name(), value: glucoseFormatter.string(from: eventual) ?? "??", unit: ""))

case .deltaBg:
return BottomRowItem.generic(label: type.name(), value: delta, unit: "")
items.append(BottomRowItem.generic(label: type.name(), value: delta, unit: ""))

case .updatedAt:
return BottomRowItem.generic(label: type.name(), value: timeFormatter.string(from: Date.now), unit: "")
items.append(BottomRowItem.generic(label: type.name(), value: timeFormatter.string(from: Date.now), unit: ""))
}
}
}
return items
}

private func initEmptyActivity(settings: LiveActivitySettings) {
Expand Down