refactor: unify BuildOperationMetrics into a single struct with counters

Instead of using an enum with separate CacheMetrics and CounterMetrics
associated values, use a single struct with counters/taskCounters fields.
The legacy Xcode 15.3 - Xcode 26.3 cache format (clangCacheHits, etc.)
is translated into the unified counter format during deserialization.

Signed-off-by: Kohki Miki <kohki.miki@lycorp.co.jp>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: giginet

Sources/XCLogParser/activityparser/IDEActivityModel.swift

@@ -774,41 +774,39 @@ public class IDEActivityLogSectionAttachment: Encodable {
     }
 
     /// Build operation metrics whose JSON schema differs by Xcode version.
-    public enum BuildOperationMetrics: Encodable {
-        /// Xcode 15.3 - Xcode 16.x format
-        case v15_3(CacheMetrics)
-        /// Xcode 26.4+ format
-        case v26_4(CounterMetrics)
-
-        public struct CacheMetrics: Codable {
-            public let clangCacheHits: Int
-            public let clangCacheMisses: Int
-            public let swiftCacheHits: Int
-            public let swiftCacheMisses: Int
-        }
+    public struct BuildOperationMetrics: Codable {
+        public let counters: [String: Int]
+        public let taskCounters: [String: [String: Int]]
 
-        public struct CounterMetrics: Codable {
-            public let counters: [String: Int]
-            public let taskCounters: [String: [String: Int]]
+        public init(counters: [String: Int], taskCounters: [String: [String: Int]]) {
+            self.counters = counters
+            self.taskCounters = taskCounters
         }
 
+        /// Parses BuildOperationMetrics from JSON data, translating the legacy
+        /// Xcode 15.3 - Xcode 26.3 cache format into the unified counter format.
         public init(from jsonData: Data) throws {
             let decoder = JSONDecoder()
-            if let cache = try? decoder.decode(CacheMetrics.self, from: jsonData) {
-                self = .v15_3(cache)
+            if let direct = try? decoder.decode(BuildOperationMetrics.self, from: jsonData) {
+                self = direct
             } else {
-                let counter = try decoder.decode(CounterMetrics.self, from: jsonData)
-                self = .v26_4(counter)
+                let legacy = try decoder.decode(LegacyCacheMetrics.self, from: jsonData)
+                self.counters = [
+                    "clangCacheHits": legacy.clangCacheHits,
+                    "clangCacheMisses": legacy.clangCacheMisses,
+                    "swiftCacheHits": legacy.swiftCacheHits,
+                    "swiftCacheMisses": legacy.swiftCacheMisses,
+                ]
+                self.taskCounters = [:]
             }
         }
 
-        public func encode(to encoder: Encoder) throws {
-            switch self {
-            case .v15_3(let metrics):
-                try metrics.encode(to: encoder)
-            case .v26_4(let metrics):
-                try metrics.encode(to: encoder)
-            }
+        /// Legacy Xcode 15.3 - Xcode 26.3 format, used only for deserialization.
+        private struct LegacyCacheMetrics: Decodable {
+            let clangCacheHits: Int
+            let clangCacheMisses: Int
+            let swiftCacheHits: Int
+            let swiftCacheMisses: Int
         }
     }
 }

Tests/XCLogParserTests/ActivityParserTests.swift

@@ -420,10 +420,10 @@ class ActivityParserTests: XCTestCase {
         XCTAssertEqual(3, logSection.attachments.count)
         XCTAssertEqual(logSection.attachments[0].backtrace?.frames.first?.category, .ruleNeverBuilt)
         print(logSection.attachments)
-        if case .some(.v15_3(let cache)) = logSection.attachments[1].buildOperationMetrics {
-            XCTAssertEqual(cache.clangCacheMisses, 2)
+        if let metrics = logSection.attachments[1].buildOperationMetrics {
+            XCTAssertEqual(metrics.counters["clangCacheMisses"], 2)
         } else {
-            XCTFail("Expected v15_3 BuildOperationMetrics")
+            XCTFail("Expected BuildOperationMetrics")
         }
         XCTAssertEqual(logSection.attachments[2].metrics?.wcDuration, 1)
         XCTAssertEqual(0, logSection.unknown)
@@ -510,11 +510,11 @@ class ActivityParserTests: XCTestCase {
         XCTAssertEqual("localizedResultString", logSection.localizedResultString)
         XCTAssertEqual("xcbuildSignature", logSection.xcbuildSignature)
         XCTAssertEqual(1, logSection.attachments.count)
-        if case .some(.v26_4(let counter)) = logSection.attachments[0].buildOperationMetrics {
-            XCTAssertEqual(counter.counters, [:])
-            XCTAssertEqual(counter.taskCounters["SwiftDriver"]?["moduleDependenciesNotValidatedTasks"], 1)
+        if let metrics = logSection.attachments[0].buildOperationMetrics {
+            XCTAssertEqual(metrics.counters, [:])
+            XCTAssertEqual(metrics.taskCounters["SwiftDriver"]?["moduleDependenciesNotValidatedTasks"], 1)
         } else {
-            XCTFail("Expected v26_4 BuildOperationMetrics")
+            XCTFail("Expected BuildOperationMetrics")
         }
         XCTAssertEqual(42, logSection.unknown)
     }
@@ -640,26 +640,19 @@ class ActivityParserTests: XCTestCase {
         let json = #"{"clangCacheHits":1,"clangCacheMisses":2,"swiftCacheHits":3,"swiftCacheMisses":4}"#
         let data = json.data(using: .utf8)!
         let metrics = try IDEActivityLogSectionAttachment.BuildOperationMetrics(from: data)
-        if case .v15_3(let cache) = metrics {
-            XCTAssertEqual(cache.clangCacheHits, 1)
-            XCTAssertEqual(cache.clangCacheMisses, 2)
-            XCTAssertEqual(cache.swiftCacheHits, 3)
-            XCTAssertEqual(cache.swiftCacheMisses, 4)
-        } else {
-            XCTFail("Expected v15_3 BuildOperationMetrics")
-        }
+        XCTAssertEqual(metrics.counters["clangCacheHits"], 1)
+        XCTAssertEqual(metrics.counters["clangCacheMisses"], 2)
+        XCTAssertEqual(metrics.counters["swiftCacheHits"], 3)
+        XCTAssertEqual(metrics.counters["swiftCacheMisses"], 4)
+        XCTAssertEqual(metrics.taskCounters, [:])
     }
 
     func testBuildOperationMetricsWithCounterFormat() throws {
         let json = #"{"counters":{"a":1},"taskCounters":{"SwiftDriver":{"x":2}}}"#
         let data = json.data(using: .utf8)!
         let metrics = try IDEActivityLogSectionAttachment.BuildOperationMetrics(from: data)
-        if case .v26_4(let counter) = metrics {
-            XCTAssertEqual(counter.counters["a"], 1)
-            XCTAssertEqual(counter.taskCounters["SwiftDriver"]?["x"], 2)
-        } else {
-            XCTFail("Expected v26_4 BuildOperationMetrics")
-        }
+        XCTAssertEqual(metrics.counters["a"], 1)
+        XCTAssertEqual(metrics.taskCounters["SwiftDriver"]?["x"], 2)
     }
 
 }