Include app version in GitHub PR poller User-Agent

Packages/macOS/CmuxGit/Sources/CmuxGit/Probe/GitHubPullRequestRequestCoordinator.swift

@@ -16,6 +16,34 @@ public actor GitHubPullRequestRequestCoordinator {
     private static let maximumConcurrentTransportCount = 3
     private static let maximumRateLimitIdentityCount = 32
 
+    /// Product token that identifies cmux's pull-request poller in the GitHub `User-Agent` header.
+    private static let userAgentProductToken = "cmux-workspace-pr-poller"
+
+    /// `User-Agent` sent with every pull-request probe, formatted as `Product/Version`.
+    ///
+    /// The version is resolved once from the host app bundle's
+    /// `CFBundleShortVersionString`, so it always reflects the shipped release
+    /// without any manual update. Formatting is factored into
+    /// `userAgentValue(appVersion:)` so it can be unit-tested without depending
+    /// on the bundle.
+    private static let userAgentHeaderValue = userAgentValue(
+        appVersion: Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String
+    )
+
+    /// Builds the poller `User-Agent`, appending the app version when available.
+    ///
+    /// The product token is always emitted as the leading component so
+    /// server-side matching on `cmux-workspace-pr-poller` keeps working. When no
+    /// version is available the token is paired with `unknown` to preserve the
+    /// `Product/Version` shape.
+    static func userAgentValue(appVersion: String?) -> String {
+        let version = appVersion?.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard let version, !version.isEmpty else {
+            return "\(userAgentProductToken)/unknown"
+        }
+        return "\(userAgentProductToken)/\(version)"
+    }
+
     internal struct RequestKey: Hashable, Sendable {
         let endpoint: String
         let authorizationFingerprint: Data
@@ -173,7 +201,7 @@ public actor GitHubPullRequestRequestCoordinator {
         var request = URLRequest(url: url)
         request.httpMethod = "GET"
         request.setValue("application/vnd.github+json", forHTTPHeaderField: "Accept")
-        request.setValue("cmux-workspace-pr-poller", forHTTPHeaderField: "User-Agent")
+        request.setValue(Self.userAgentHeaderValue, forHTTPHeaderField: "User-Agent")
         request.setValue(authHeader, forHTTPHeaderField: "Authorization")
         let cachedResponse = cachedResponseByRequestKey[requestKey]
         if let cachedResponse {

Packages/macOS/CmuxGit/Tests/CmuxGitTests/GitHubPullRequestRequestTests.swift

@@ -420,4 +420,47 @@ struct GitHubPullRequestRequestTests {
         #expect(await survivor.value?.statusCode == 200)
         #expect(GitHubPullRequestStubURLProtocol.capturedRequests().count == 1)
     }
+
+    @Test func userAgentValueAppendsAppVersion() {
+        #expect(
+            GitHubPullRequestRequestCoordinator.userAgentValue(appVersion: "1.2.3")
+                == "cmux-workspace-pr-poller/1.2.3"
+        )
+    }
+
+    @Test func userAgentValueTrimsSurroundingWhitespace() {
+        #expect(
+            GitHubPullRequestRequestCoordinator.userAgentValue(appVersion: "  0.64.21  ")
+                == "cmux-workspace-pr-poller/0.64.21"
+        )
+    }
+
+    @Test func userAgentValueFallsBackWhenVersionMissing() {
+        #expect(
+            GitHubPullRequestRequestCoordinator.userAgentValue(appVersion: nil)
+                == "cmux-workspace-pr-poller/unknown"
+        )
+        #expect(
+            GitHubPullRequestRequestCoordinator.userAgentValue(appVersion: "   ")
+                == "cmux-workspace-pr-poller/unknown"
+        )
+    }
+
+    @Test func pollerRequestSendsProductTokenUserAgent() async {
+        GitHubPullRequestStubURLProtocol.reset(stubs: [
+            .init(statusCode: 200, data: Data("[]".utf8)),
+        ])
+        let coordinator = GitHubPullRequestRequestCoordinator(session: makeSession())
+
+        _ = await coordinator.response(endpoint: endpoint, authHeader: "******")
+
+        let userAgent = GitHubPullRequestStubURLProtocol.capturedRequests()
+            .first?
+            .value(forHTTPHeaderField: "User-Agent")
+        let expected = GitHubPullRequestRequestCoordinator.userAgentValue(
+            appVersion: Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String
+        )
+        #expect(userAgent == expected)
+        #expect(userAgent?.hasPrefix("cmux-workspace-pr-poller/") == true)
+    }
 }