Adopt swift-format, enforce lint in CI

.git-blame-ignore-revs

@@ -0,0 +1,3 @@
+# Mass-reformat with swift-format; use this file to skip it in blame.
+# git config blame.ignoreRevsFile .git-blame-ignore-revs
+ca4d5e37c1ca313471f7b5634093c74784a8452f

.github/workflows/ci.yml

@@ -334,3 +334,17 @@ jobs:
         env:
           TWOMLSPQ_LOCAL_XCFRAMEWORK: "1"
         run: swift test
+
+  swift-lint:
+    name: Swift format lint
+    runs-on: macos-15
+    steps:
+      - uses: actions/checkout@v4
+      - uses: swift-actions/setup-swift@v2
+        with:
+          swift-version: "6.1"
+      # --strict: warnings fail the job too, not only errors. Scoped to the hand-written
+      # target + tests — Sources/TwoMLSPQBinding/two_mls_pq.swift is uniffi-autogenerated
+      # ("don't mess with it", swiftlint disabled) and gets re-synced from the Rust build
+      # on every release, so linting it here would just drift again on the next re-sync.
+      - run: swift format lint --recursive --configuration .swift-format --strict Sources/TwoMLSPQ Tests

Sources/TwoMLSPQ/SessionErrorBridge.swift

@@ -107,14 +107,16 @@ extension SessionError {
 				case .receive:
 					// Establishment door: the commitment the host threaded in from
 					// the signed AppWelcome is not a valid H(A.3 key package).
-					detail = "bootstrap-KP commitment is not H(the initiator's PQ "
+					detail =
+						"bootstrap-KP commitment is not H(the initiator's PQ "
 						+ "key package): a malformed or mis-read 32-byte value, or a "
 						+ "tampered AppWelcome. The invitation is NOT consumed — "
 						+ "re-read the commitment from the signed envelope and retry."
 				default:
 					// A.3 side-band: a KP′ that hashes to something other than the
 					// commitment the signed envelope pinned.
-					detail = "A.3 bootstrap key package (KP′) does not hash to the "
+					detail =
+						"A.3 bootstrap key package (KP′) does not hash to the "
 						+ "commitment the signed establishment envelope carried — a "
 						+ "substituted or tampered KP′. Discard the frame; the genuine "
 						+ "re-stapled KP′ still applies, session state untouched."
@@ -142,25 +144,29 @@ extension SessionError {
 					// Initiator: a bare welcome whose creator differs from the invitation
 					// identity — a born-dedicated establishment must arrive enveloped.
 					code = .establishmentEnvelopeRequired
-					detail = "a born-dedicated establishment arrived un-enveloped (creator "
+					detail =
+						"a born-dedicated establishment arrived un-enveloped (creator "
 						+ "leaf differs from the invitation identity); refused so an "
 						+ "undelegated credential cannot be admitted on the weld alone."
 				default:
 					// Acceptor: an emission door was driven before the signed delegation
 					// was installed — a caller-sequencing bug.
 					code = .sequenceViolation
-					detail = "born-dedicated session is non-emittable until "
+					detail =
+						"born-dedicated session is non-emittable until "
 						+ "installEstablishmentEnvelope supplies the signed delegation; "
 						+ "mint and install it before sending."
 				}
 			case .EstablishmentCreatorMismatch:
 				code = .establishmentCreatorMismatch
-				detail = "the admitted creator id does not match the welcome's creator leaf: "
+				detail =
+					"the admitted creator id does not match the welcome's creator leaf: "
 					+ "the delegation is genuine but names a different key. The join was "
 					+ "discarded whole; do not retry with the same admittedCreator."
 			case .EstablishmentEnvelopeConflict:
 				code = .establishmentEnvelopeConflict
-				detail = "a different establishment envelope is already installed on this "
+				detail =
+					"a different establishment envelope is already installed on this "
 					+ "session; one session binds exactly one envelope."
 			case .AttachmentComponentUnavailable:
 				code = .attachmentComponentUnavailable

Tests/TwoMLSPQTests/AttachmentCEKTests.swift

@@ -12,7 +12,6 @@
 import CommProtocol
 import Foundation
 import Testing
-
 import TwoMLSPQBinding
 
 @testable import TwoMLSPQ
@@ -71,11 +70,14 @@ struct AttachmentCEKTests {
 		let (local, _) = try establishedPair()
 		_ = try local.prepareToEncrypt(proposing: nil)
 
-		let cekA = try local.exportAttachmentCEKSend(keyId: Data(repeating: 0x01, count: 32))
-		let cekB = try local.exportAttachmentCEKSend(keyId: Data(repeating: 0x02, count: 32))
+		let cekA = try local.exportAttachmentCEKSend(
+			keyId: Data(repeating: 0x01, count: 32))
+		let cekB = try local.exportAttachmentCEKSend(
+			keyId: Data(repeating: 0x02, count: 32))
 		#expect(cekA != cekB, "distinct key ids must not collide within one epoch")
 
-		let cekAAgain = try local.exportAttachmentCEKSend(keyId: Data(repeating: 0x01, count: 32))
+		let cekAAgain = try local.exportAttachmentCEKSend(
+			keyId: Data(repeating: 0x01, count: 32))
 		#expect(cekA == cekAAgain, "the same (epoch, keyId) must re-derive identically")
 	}
 

Tests/TwoMLSPQTests/ErrorContractTests.swift

@@ -13,7 +13,6 @@
 
 import Foundation
 import Testing
-
 import TwoMLSPQBinding  // public TwoMlsPqError cases
 
 @testable import TwoMLSPQ  // internal SessionError(pqError:at:) + PQErrorSurface
@@ -124,7 +123,9 @@ struct ErrorContractTests {
 			let e = SessionError(pqError: TwoMlsPqError.SessionNotReady, at: surface)
 			#expect(e.code == .misroutedFrame, "\(surface)")
 		}
-		let sequencing: [PQErrorSurface] = [.prepareToEncrypt, .encrypt, .pqOperation, .receive]
+		let sequencing: [PQErrorSurface] = [
+			.prepareToEncrypt, .encrypt, .pqOperation, .receive,
+		]
 		for surface in sequencing {
 			let e = SessionError(pqError: TwoMlsPqError.SessionNotReady, at: surface)
 			#expect(e.code == .sequenceViolation, "\(surface)")

Tests/TwoMLSPQTests/LifecycleTests.swift

@@ -12,7 +12,6 @@
 import CommProtocol
 import Foundation
 import Testing
-
 import TwoMLSPQBinding
 
 @testable import TwoMLSPQ
@@ -198,7 +197,9 @@ struct LifecycleTests {
 		let kp = try localSession.finishBootstrap(rotating: nil)
 		#expect(kp.kind == .finishBootstrap)
 		// Bootstrap key-package frame — classify by opening the seal (wire tag sealed, v7).
-		#expect(try remoteBase.openIncoming(blob: kp.payload)?.kind == .pqSideBand(kind: .bootstrapKeyPackage))
+		#expect(
+			try remoteBase.openIncoming(blob: kp.payload)?.kind
+				== .pqSideBand(kind: .bootstrapKeyPackage))
 
 		let remoteClassicalBefore = remoteBase.epochs().classicalEpoch
 		let remoteListenBeforeBootstrap = try remoteBase.shouldListenOn()
@@ -225,13 +226,17 @@ struct LifecycleTests {
 		let peek1 = try #require(remoteSession.pendingSideBand(sealing: .fresh))
 		let peek2 = try #require(remoteSession.pendingSideBand(sealing: .fresh))
 		#expect(peek1 != peek2)
-		#expect(try localBase.openIncoming(blob: peek1)?.kind == .pqSideBand(kind: .bootstrapWelcome))
+		#expect(
+			try localBase.openIncoming(blob: peek1)?.kind
+				== .pqSideBand(kind: .bootstrapWelcome))
 
 		let reply = try #require(remoteSession.advance(after: inbound))
 		#expect(reply.kind == .finishBootstrap)
 		// The responder's reply is the new PQ group's Welcome' (v18: the bind is no
 		// longer a side-band frame kind — it rides the message-frame staple).
-		#expect(try localBase.openIncoming(blob: reply.payload)?.kind == .pqSideBand(kind: .bootstrapWelcome))
+		#expect(
+			try localBase.openIncoming(blob: reply.payload)?.kind
+				== .pqSideBand(kind: .bootstrapWelcome))
 		// The consuming take hands the frame out exactly once — retention included.
 		#expect(remoteSession.advance(after: inbound) == nil)
 		#expect(remoteSession.pendingSideBand(sealing: .fresh) == nil)
@@ -272,18 +277,22 @@ struct LifecycleTests {
 		// (A.5 as a rotation credential catch-up is exercised in the Rust crate suite.)
 		#expect(remoteSession.turn == .weInitiate)
 		let remotePqBeforeRatchet = remoteBase.epochs().pqEpoch
-		try remoteSession.send(to: localSession) // opener — auto-stages Remote's A.4 EK
+		try remoteSession.send(to: localSession)  // opener — auto-stages Remote's A.4 EK
 		let ratchetEk = try #require(remoteSession.pendingSideBand(sealing: .fresh))
 		// EK frame — classify by opening the seal (wire tag sealed, v7).
-		#expect(try localBase.openIncoming(blob: ratchetEk)?.kind == .pqSideBand(kind: .ratchetEphemeralKey))
+		#expect(
+			try localBase.openIncoming(blob: ratchetEk)?.kind
+				== .pqSideBand(kind: .ratchetEphemeralKey))
 
 		// Local responds: seals the injected secret to the EK, parking the CT reply.
 		let ratchetInbound1 = try localSession.ingest(ratchetEk)
 		#expect(ratchetInbound1.kind == .ratchet)
 		let ratchetReply = try #require(localSession.advance(after: ratchetInbound1))
 		#expect(ratchetReply.kind == .ratchet)
 		// CT frame — classify by opening the seal.
-		#expect(try remoteBase.openIncoming(blob: ratchetReply.payload)?.kind == .pqSideBand(kind: .ratchetCiphertext))
+		#expect(
+			try remoteBase.openIncoming(blob: ratchetReply.payload)?.kind
+				== .pqSideBand(kind: .ratchetCiphertext))
 		// The consuming take hands the frame out exactly once.
 		#expect(localSession.advance(after: ratchetInbound1) == nil)
 
@@ -304,10 +313,13 @@ struct LifecycleTests {
 		// -- Step 8: exchanges still flow on the ratcheted groups.
 		try localSession.exchange(with: remoteSession)
 		_ = try remoteSession.prepareToEncrypt(proposing: nil)
-		let postRatchetFrame = try remoteSession.encrypt(appMessage: Data("post-ratchet".utf8))
+		let postRatchetFrame = try remoteSession.encrypt(
+			appMessage: Data("post-ratchet".utf8))
 		let postRatchet = try #require(
 			try localSession.decrypt(postRatchetFrame.cipherText))
-		#expect(try postRatchet.applicationMessage.tryUnwrap.appMessageData == Data("post-ratchet".utf8))
+		#expect(
+			try postRatchet.applicationMessage.tryUnwrap.appMessageData
+				== Data("post-ratchet".utf8))
 	}
 
 	/// The poster's post address is its recv group's current exporter; the recv

Tests/TwoMLSPQTests/PQInvitationTests.swift

@@ -10,7 +10,6 @@
 import CommProtocol
 import Foundation
 import Testing
-
 import TwoMLSPQ
 import TwoMLSPQBinding
 
@@ -47,7 +46,8 @@ struct PQInvitationReceiveTests {
 		let (acceptorSession, stapled) = try invitation.receive(
 			sendGroupWelcome: welcome,
 			remoteKeyPackage: initiatorKp,
-			bootstrapKpCommitment: try #require(initiatorSession.bootstrapKpCommitment()),
+			bootstrapKpCommitment: try #require(
+				initiatorSession.bootstrapKpCommitment()),
 			remoteClientId: initiator.clientId().bytes,
 			welcomeToken: WelcomeToken(PQDigest.over(welcome)),
 			stapledMessage: nil,
@@ -63,16 +63,21 @@ struct PQInvitationReceiveTests {
 		let back = try acceptorSession.encrypt(appMessage: "hello back".utf8Data)
 		let received = try #require(
 			try approveEstablishmentRaw(
-				initiator: initiatorSession, ciphertext: back.cipherText, dedicatedId: dedicatedId)
+				initiator: initiatorSession, ciphertext: back.cipherText,
+				dedicatedId: dedicatedId)
 		)
 		#expect(received.applicationMessage?.appMessageData == "hello back".utf8Data)
 
 		// And a routine round now that the initiator is fully established.
 		_ = try initiatorSession.prepareToEncrypt(proposing: nil)
 		let routine = try initiatorSession.encrypt(appMessage: "routine".utf8Data)
-		guard case .decrypted(let decrypted) =
-			try acceptorSession.processIncoming(ciphertext: routine.cipherText)
-		else { Issue.record("unexpected establishment pause"); throw TestErrors.unexpected }
+		guard
+			case .decrypted(let decrypted) =
+				try acceptorSession.processIncoming(ciphertext: routine.cipherText)
+		else {
+			Issue.record("unexpected establishment pause")
+			throw TestErrors.unexpected
+		}
 		#expect(
 			try decrypted.tryUnwrap.applicationMessage.tryUnwrap.appMessageData
 				== "routine".utf8Data
@@ -185,7 +190,8 @@ struct PQInvitationReceiveTests {
 			_ = try invitation.receive(
 				sendGroupWelcome: welcome,
 				remoteKeyPackage: initiatorKp,
-				bootstrapKpCommitment: Data(repeating: 0, count: 31),  // one byte short of a SHA-256
+				// one byte short of a SHA-256
+				bootstrapKpCommitment: Data(repeating: 0, count: 31),
 				remoteClientId: initiator.clientId().bytes,
 				welcomeToken: token,
 				stapledMessage: nil,
@@ -207,7 +213,8 @@ struct PQInvitationReceiveTests {
 		let (acceptorSession, stapled) = try invitation.receive(
 			sendGroupWelcome: welcome,
 			remoteKeyPackage: initiatorKp,
-			bootstrapKpCommitment: try #require(initiatorSession.bootstrapKpCommitment()),
+			bootstrapKpCommitment: try #require(
+				initiatorSession.bootstrapKpCommitment()),
 			remoteClientId: initiator.clientId().bytes,
 			welcomeToken: token,
 			stapledMessage: nil,
@@ -220,7 +227,8 @@ struct PQInvitationReceiveTests {
 		let back = try acceptorSession.encrypt(appMessage: "established".utf8Data)
 		let received = try #require(
 			try approveEstablishmentRaw(
-				initiator: initiatorSession, ciphertext: back.cipherText, dedicatedId: dedicatedId)
+				initiator: initiatorSession, ciphertext: back.cipherText,
+				dedicatedId: dedicatedId)
 		)
 		#expect(received.applicationMessage?.appMessageData == "established".utf8Data)
 	}

Tests/TwoMLSPQTests/TestSupport.swift

@@ -37,7 +37,9 @@ extension PQSession {
 	/// returning the bytes for the peer-side approval.
 	@discardableResult
 	func installMockEstablishmentEnvelope() throws -> Data {
-		#expect(pendingEstablishmentWelcome != nil, "a born-dedicated acceptor owes a welcome")
+		#expect(
+			pendingEstablishmentWelcome != nil,
+			"a born-dedicated acceptor owes a welcome")
 		try installEstablishmentEnvelope(mockEstablishmentEnvelope)
 		return mockEstablishmentEnvelope
 	}
@@ -54,13 +56,17 @@ extension PQSession {
 	) throws -> PQDecryptResult? {
 		_ = try acceptor.prepareToEncrypt(proposing: nil)
 		let frame = try acceptor.encrypt(appMessage: message)
-		guard case .pendingEstablishment(let pending) = try processIncoming(ciphertext: frame.cipherText)
+		guard
+			case .pendingEstablishment(let pending) = try processIncoming(
+				ciphertext: frame.cipherText)
 		else {
 			Issue.record("expected a born-dedicated establishment pause")
 			throw TestErrors.unexpected
 		}
 		#expect(pending.envelope == mockEstablishmentEnvelope)
-		#expect(pending.welcome.first == 0x01, "the surfaced welcome is a bare APQWelcome_A")
+		#expect(
+			pending.welcome.first == 0x01, "the surfaced welcome is a bare APQWelcome_A"
+		)
 		return try pending.resume(admittedCreator: dedicatedId)
 	}
 }
@@ -109,7 +115,8 @@ extension PQSession {
 	/// pause) and return its payload. For frames past establishment, where a pause
 	/// cannot occur — a pause here is a test-setup bug, surfaced loudly.
 	func decrypt(_ ciphertext: Data) throws -> PQDecryptResult? {
-		guard case .decrypted(let result) = try processIncoming(ciphertext: ciphertext) else {
+		guard case .decrypted(let result) = try processIncoming(ciphertext: ciphertext)
+		else {
 			Issue.record("unexpected establishment pause on a post-establishment frame")
 			throw TestErrors.unexpected
 		}
@@ -126,9 +133,11 @@ extension PQSession {
 
 		// Post-establishment: the receiver decrypts. (A born-dedicated first frame
 		// pauses instead — that path is `acceptEstablishment`, not `send`.)
-		guard case .decrypted(let decrypted) = try remote.processIncoming(
-			ciphertext: encryptedOutgoing.cipherText
-		) else {
+		guard
+			case .decrypted(let decrypted) = try remote.processIncoming(
+				ciphertext: encryptedOutgoing.cipherText
+			)
+		else {
 			Issue.record("unexpected establishment pause in a steady-state send")
 			throw TestErrors.unexpected
 		}