Record G5/G6 states without reliable glucose as sensorIssue events

CGMBLEKit.xcodeproj/project.pbxproj

@@ -59,6 +59,7 @@
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 		43880F981D9E19FC009061A8 /* TransmitterVersionRxMessage.swift in Sources */ = {isa = PBXBuildFile; fileRef = 43880F971D9E19FC009061A8 /* TransmitterVersionRxMessage.swift */; };
 		43880F9A1D9E1BD7009061A8 /* TransmitterVersionRxMessageTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 43880F991D9E1BD7009061A8 /* TransmitterVersionRxMessageTests.swift */; };
+		CA05000000000000000010C2 /* SensorIssueTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA05000000000000000010C1 /* SensorIssueTests.swift */; };
 		CA04000000000000000010C2 /* AnubisDetectionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = CA04000000000000000010C1 /* AnubisDetectionTests.swift */; };
 		43A8EC4A210D09BE00A81379 /* LoopKitUI.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 43A8EC49210D09BE00A81379 /* LoopKitUI.framework */; };
 		43A8EC4C210D09DA00A81379 /* LoopKitUI.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 43A8EC49210D09BE00A81379 /* LoopKitUI.framework */; };
@@ -387,6 +388,7 @@
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 		43880F971D9E19FC009061A8 /* TransmitterVersionRxMessage.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransmitterVersionRxMessage.swift; sourceTree = "<group>"; };
 		43880F991D9E1BD7009061A8 /* TransmitterVersionRxMessageTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TransmitterVersionRxMessageTests.swift; sourceTree = "<group>"; };
+		CA05000000000000000010C1 /* SensorIssueTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SensorIssueTests.swift; sourceTree = "<group>"; };
 		CA04000000000000000010C1 /* AnubisDetectionTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AnubisDetectionTests.swift; sourceTree = "<group>"; };
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@@ -727,6 +729,7 @@
 				43F82BCB1D035AA4006F5DD7 /* TransmitterTimeRxMessageTests.swift */,
 				43880F991D9E1BD7009061A8 /* TransmitterVersionRxMessageTests.swift */,
 				CA04000000000000000010C1 /* AnubisDetectionTests.swift */,
+				CA05000000000000000010C1 /* SensorIssueTests.swift */,
 			);
 			path = CGMBLEKitTests;
 			sourceTree = "<group>";
@@ -1275,6 +1278,7 @@
 				43E397911D5692080028E321 /* GlucoseTests.swift in Sources */,
 				43880F9A1D9E1BD7009061A8 /* TransmitterVersionRxMessageTests.swift in Sources */,
 				CA04000000000000000010C2 /* AnubisDetectionTests.swift in Sources */,
+				CA05000000000000000010C2 /* SensorIssueTests.swift in Sources */,
 				43DC87C21C8B520F005BC30D /* GlucoseRxMessageTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

CGMBLEKit/TransmitterManager.swift

@@ -344,6 +344,7 @@ public class TransmitterManager: TransmitterDelegate {
         if state.sensorStartOffset != sensorStartOffset {
             mutateState { state in
                 state.sensorStartOffset = sensorStartOffset
+                state.reportedSensorIssue = nil
             }
             if let sessionStartDate = glucose.sessionStartDate {
                 events.append(PersistedCgmEvent(
@@ -358,6 +359,19 @@ public class TransmitterManager: TransmitterDelegate {
             }
         }
 
+        var sensorIssue: String?
+        mutateState { state in
+            sensorIssue = state.newSensorIssue(for: glucose.state)
+        }
+        if let sensorIssue {
+            events.append(PersistedCgmEvent(
+                date: glucose.readDate,
+                type: .sensorIssue,
+                deviceIdentifier: transmitter.ID,
+                error: CgmEventError(code: sensorIssue, isFatal: glucose.state.sensorFailed)
+            ))
+        }
+
         // Filter out future-dated events
         // Stopgap measure for the issue described in https://github.com/LoopKit/Loop/issues/2087
         events = events.filter { event in
@@ -610,6 +624,15 @@ extension CalibrationError: LocalizedError {
 }
 
 extension CalibrationState {
+    var sensorFailed: Bool {
+        switch self {
+        case .known(.sensorFailure11), .known(.sensorFailure12), .known(.sessionFailure15), .known(.sessionFailure16), .known(.sessionFailure17):
+            return true
+        default:
+            return false
+        }
+    }
+
     public var localizedDescription: String {
         switch self {
         case .known(let state):

CGMBLEKit/TransmitterManagerState.swift

@@ -40,6 +40,9 @@ public struct TransmitterManagerState: RawRepresentable, Equatable {
     /// User-configured session length; only honored for Anubis (see `sensorLife`).
     public var sensorLifeDays: Int
 
+    /// The state last recorded as a `sensorIssue` this session; nil once glucose is reliable.
+    public var reportedSensorIssue: String?
+
     public init(
         transmitterID: String,
         shouldSyncToRemoteService: Bool = true,
@@ -81,6 +84,7 @@ public struct TransmitterManagerState: RawRepresentable, Equatable {
             transmitterExpiryInDays: transmitterExpiryInDays,
             sensorLifeDays: sensorLifeDays
         )
+        self.reportedSensorIssue = rawValue["reportedSensorIssue"] as? String
     }
 
     public var rawValue: RawValue {
@@ -93,10 +97,23 @@ public struct TransmitterManagerState: RawRepresentable, Equatable {
         rval["sensorStartOffset"] = sensorStartOffset
         rval["transmitterExpiryInDays"] = transmitterExpiryInDays.map { Int($0) }
         rval["sensorLifeDays"] = sensorLifeDays
+        rval["reportedSensorIssue"] = reportedSensorIssue
 
         return rval
     }
 
+    /// The state to record as a `sensorIssue`, when `calibrationState` lacks reliable glucose and
+    /// differs from the last one recorded. A reliable reading clears it, so a state that returns
+    /// after recovery is recorded again.
+    mutating func newSensorIssue(for calibrationState: CalibrationState) -> String? {
+        let issue = calibrationState.hasReliableGlucose ? nil : calibrationState.description
+        guard issue != reportedSensorIssue else {
+            return nil
+        }
+        reportedSensorIssue = issue
+        return issue
+    }
+
     /// `true` once the transmitter has reported the Anubis 180-day lifetime.
     public var isAnubis: Bool {
         return transmitterExpiryInDays == 180

CGMBLEKitTests/SensorIssueTests.swift

@@ -0,0 +1,38 @@
+//
+//  SensorIssueTests.swift
+//  CGMBLEKitTests
+//
+//  Copyright © 2026 LoopKit Authors. All rights reserved.
+//
+
+import XCTest
+@testable import CGMBLEKit
+
+class SensorIssueTests: XCTestCase {
+
+    func testEachStateIsReportedOnceUntilGlucoseIsReliable() {
+        var state = TransmitterManagerState(transmitterID: "8G1234")
+        let readings: [CalibrationState.State] = [.warmup, .warmup, .ok, .questionMarks, .questionMarks, .needCalibration7, .warmup]
+
+        let issues = readings.compactMap { state.newSensorIssue(for: .known($0)) }
+
+        XCTAssertEqual(issues, ["warmup", "questionMarks", "warmup"])
+        XCTAssertEqual(state.reportedSensorIssue, "warmup")
+    }
+
+    func testReportedIssueSurvivesARelaunch() {
+        var state = TransmitterManagerState(transmitterID: "8G1234")
+        XCTAssertEqual(state.newSensorIssue(for: .known(.sensorFailure11)), "sensorFailure11")
+
+        var restored = TransmitterManagerState(rawValue: state.rawValue)!
+
+        XCTAssertEqual(restored.reportedSensorIssue, "sensorFailure11")
+        XCTAssertNil(restored.newSensorIssue(for: .known(.sensorFailure11)))
+    }
+
+    func testFailureStates() {
+        XCTAssertTrue(CalibrationState.known(.sessionFailure16).sensorFailed)
+        XCTAssertFalse(CalibrationState.known(.warmup).sensorFailed)
+        XCTAssertFalse(CalibrationState.unknown(99).sensorFailed)
+    }
+}