Introduce SwiftFormat (#339)

Author: patrickfreed

.swiftformat

@@ -0,0 +1,36 @@
+--exclude Sources/MongoSwift/MongoSwiftVersion.swift
+
+# unnecessary
+--disable andOperator
+
+# put #if to the first column
+--ifdef "outdent"
+
+# 4 spaces
+--indent 4
+
+# 0..<3 vs 0 ..< 3
+--ranges "no-space"
+
+# always want explicit acl
+--disable redundantExtensionACL
+
+# always want explicit self
+--self insert
+
+# don't need semicolons
+--semicolons "never"
+
+--disable trailingCommas
+
+# first element of collection on newline after opening brace/bracket
+--wrapcollections "before-first"
+
+# put first argument on its own line
+--wraparguments "before-first"
+
+# if x == 1 vs if 1 == x
+--disable yodaConditions
+
+# the ordering doesn't match linter's
+--disable specifiers

.swiftlint.yml

@@ -53,6 +53,7 @@ excluded:
   - Package.swift
   - Examples/*/Package.swift
   - Tests/LinuxMain.swift
+  - SwiftFormat # this is the path we download SwiftFormat to on travis
 
 trailing_whitespace:
   ignores_comments: false

.travis.yml

@@ -19,6 +19,14 @@ jobs:
         - make linuxmain SOURCERY=${PWD}/sourcery/bin/sourcery
         - git diff --exit-code Tests/LinuxMain.swift
 
+    - stage: pre-tests
+      name: lint
+      os: osx
+      osx_image: xcode11.1
+      install: ./Tests/Scripts/install_dependencies.sh swiftlint && ./Tests/Scripts/install_dependencies.sh swiftformat
+      before_script: skip
+      script: ${PWD}/swiftlint/swiftlint --strict && ${PWD}/SwiftFormat/CommandLineTool/swiftformat --verbose --lint .
+
     - stage: tests
       os: osx
       osx_image: xcode10.2
@@ -35,15 +43,6 @@ jobs:
       script: make coverage
       after_success: bash <(curl -s https://codecov.io/bash)
 
-    - stage: post-tests
-      name: lint
-      os: osx
-      osx_image: xcode11.1
-      install: ./Tests/Scripts/install_dependencies.sh swiftlint
-      before_script: skip
-      script: ${PWD}/swiftlint/swiftlint --strict
-
-
 install:
   - INSTALLER=Tests/Scripts/install_dependencies.sh
   - ./${INSTALLER} libmongoc

Examples/BugReport/Package.swift

@@ -4,11 +4,12 @@ import PackageDescription
 let package = Package(
     name: "BugReport",
     dependencies: [
-         .package(url: "https://github.com/mongodb/mongo-swift-driver", .upToNextMajor(from: "0.1.0"))
+        .package(url: "https://github.com/mongodb/mongo-swift-driver", .upToNextMajor(from: "0.1.0"))
     ],
     targets: [
         .target(
             name: "BugReport",
-            dependencies: ["MongoSwift"])
+            dependencies: ["MongoSwift"]
+        )
     ]
 )

Examples/Docs/Package.swift

@@ -9,4 +9,4 @@ let package = Package(
     targets: [
         .target(name: "DocsExamples", dependencies: ["MongoSwift"])
     ]
-)
+)

Examples/Docs/Sources/DocsExamples/main.swift

@@ -11,12 +11,16 @@ private func causalConsistency() throws {
     // Start Causal Consistency Example 1
     let s1 = try client1.startSession(options: ClientSessionOptions(causalConsistency: true))
     let currentDate = Date()
-    var dbOptions = DatabaseOptions(readConcern: ReadConcern(.majority),
-                                    writeConcern: try WriteConcern(w: .majority, wtimeoutMS: 1000))
+    var dbOptions = DatabaseOptions(
+        readConcern: ReadConcern(.majority),
+        writeConcern: try WriteConcern(w: .majority, wtimeoutMS: 1000)
+    )
     let items = client1.db("test", options: dbOptions).collection("items")
-    try items.updateOne(filter: ["sku": "111", "end": BSONNull()],
-                        update: ["$set": ["end": currentDate] as Document],
-                        session: s1)
+    try items.updateOne(
+        filter: ["sku": "111", "end": BSONNull()],
+        update: ["$set": ["end": currentDate] as Document],
+        session: s1
+    )
     try items.insertOne(["sku": "nuts-111", "name": "Pecans", "start": currentDate], session: s1)
     // End Causal Consistency Example 1
 

Examples/Perfect/Package.swift

@@ -2,12 +2,12 @@
 import PackageDescription
 
 let package = Package(
-	name: "PerfectExample",
-	dependencies: [
-		.package(url: "https://github.com/PerfectlySoft/Perfect-HTTPServer.git", from: "3.0.0"),
-		.package(url: "https://github.com/mongodb/mongo-swift-driver", .upToNextMajor(from: "0.1.0")),
-	],
-	targets: [
-		.target(name: "PerfectExample", dependencies: ["PerfectHTTPServer", "MongoSwift"])
-	]
+    name: "PerfectExample",
+    dependencies: [
+        .package(url: "https://github.com/PerfectlySoft/Perfect-HTTPServer.git", from: "3.0.0"),
+        .package(url: "https://github.com/mongodb/mongo-swift-driver", .upToNextMajor(from: "0.1.0")),
+    ],
+    targets: [
+        .target(name: "PerfectExample", dependencies: ["PerfectHTTPServer", "MongoSwift"])
+    ]
 )

Examples/Perfect/Sources/PerfectExample/main.swift

@@ -5,8 +5,8 @@ import PerfectHTTPServer
 
 /// A Codable type that matches the data in our home.kittens collection.
 private struct Kitten: Codable {
-	var name: String
-	var color: String
+    var name: String
+    var color: String
 }
 
 /// A single collection with type `Kitten`. This allows us to directly retrieve instances of
@@ -15,14 +15,15 @@ private let collection = try MongoClient().db("home").collection("kittens", with
 
 private var routes = Routes()
 routes.add(method: .get, uri: "/kittens") { _, response in
-	response.setHeader(.contentType, value: "application/json")
-	do {
-		let kittens = try collection.find()
-		let json = try JSONEncoder().encode(Array(kittens))
-		response.setBody(bytes: Array(json))
-	} catch {
-		print("error: \(error)")
-	}
-	response.completed()
+    response.setHeader(.contentType, value: "application/json")
+    do {
+        let kittens = try collection.find()
+        let json = try JSONEncoder().encode(Array(kittens))
+        response.setBody(bytes: Array(json))
+    } catch {
+        print("error: \(error)")
+    }
+    response.completed()
 }
+
 try HTTPServer.launch(name: "localhost", port: 8080, routes: routes)

Guides/Development.md

@@ -78,6 +78,10 @@ To regenerate the files, run `make documentation` from the project's root direct
 ## Linting and Style
 We use [SwiftLint](https://github.com/realm/SwiftLint#using-homebrew) for linting. You can see our configuration in the `.swiftlint.yml` file in the project's root directory.  Run `swiftlint` in the `/Sources` directory to lint all of our files. Running `swiftlint autocorrect` will correct some types of violations.
 
+We use [SwiftFormat](https://github.com/nicklockwood/SwiftFormat) for formatting the code. You can see our configuration in the `.swiftformat` file in the project's root directory. Our linter config contains a superset of the rules that our formatter does, so some manual tweaking may be necessary to satisfy both once the formatter is run (e.g. line length enforcement). Most of the time, the formatter should put the code into a format that passes the linter.
+
+To pass all the formatting stages of our testing matrix, both `swiftlint --strict` and `swiftformat --lint .` must finish successfully.
+
 For style guidance, look at Swift's [API design guidelines](https://swift.org/documentation/api-design-guidelines/) and Google's [Swift Style Guide](https://google.github.io/swift/).
 
 ### Sublime Text Setup

Sources/MongoSwift/APM.swift

@@ -348,108 +348,133 @@ public struct ServerHeartbeatFailedEvent: MongoEvent, InitializableFromOpaquePoi
 
 /// A callback that will be set for "command started" events if the user enables command monitoring.
 private func commandStarted(_event: OpaquePointer?) {
-    postNotification(type: CommandStartedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_command_started_get_context)
+    postNotification(
+        type: CommandStartedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_command_started_get_context
+    )
 }
 
 /// A callback that will be set for "command succeeded" events if the user enables command monitoring.
 private func commandSucceeded(_event: OpaquePointer?) {
-    postNotification(type: CommandSucceededEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_command_succeeded_get_context)
+    postNotification(
+        type: CommandSucceededEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_command_succeeded_get_context
+    )
 }
 
 /// A callback that will be set for "command failed" events if the user enables command monitoring.
 private func commandFailed(_event: OpaquePointer?) {
-    postNotification(type: CommandFailedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_command_failed_get_context)
+    postNotification(
+        type: CommandFailedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_command_failed_get_context
+    )
 }
 
 /// A callback that will be set for "server description changed" events if the user enables server monitoring.
 private func serverDescriptionChanged(_event: OpaquePointer?) {
-    postNotification(type: ServerDescriptionChangedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_changed_get_context)
+    postNotification(
+        type: ServerDescriptionChangedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_changed_get_context
+    )
 }
 
 /// A callback that will be set for "server opening" events if the user enables server monitoring.
 private func serverOpening(_event: OpaquePointer?) {
-    postNotification(type: ServerOpeningEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_opening_get_context)
+    postNotification(
+        type: ServerOpeningEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_opening_get_context
+    )
 }
 
 /// A callback that will be set for "server closed" events if the user enables server monitoring.
 private func serverClosed(_event: OpaquePointer?) {
-    postNotification(type: ServerClosedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_closed_get_context)
+    postNotification(
+        type: ServerClosedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_closed_get_context
+    )
 }
 
 /// A callback that will be set for "topology description changed" events if the user enables server monitoring.
 private func topologyDescriptionChanged(_event: OpaquePointer?) {
-    postNotification(type: TopologyDescriptionChangedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_topology_changed_get_context)
+    postNotification(
+        type: TopologyDescriptionChangedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_topology_changed_get_context
+    )
 }
 
 /// A callback that will be set for "topology opening" events if the user enables server monitoring.
 private func topologyOpening(_event: OpaquePointer?) {
-    postNotification(type: TopologyOpeningEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_topology_opening_get_context)
+    postNotification(
+        type: TopologyOpeningEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_topology_opening_get_context
+    )
 }
 
 /// A callback that will be set for "topology closed" events if the user enables server monitoring.
 private func topologyClosed(_event: OpaquePointer?) {
-    postNotification(type: TopologyClosedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_topology_closed_get_context)
+    postNotification(
+        type: TopologyClosedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_topology_closed_get_context
+    )
 }
 
 /// A callback that will be set for "server heartbeat started" events if the user enables server monitoring.
 private func serverHeartbeatStarted(_event: OpaquePointer?) {
-    postNotification(type: ServerHeartbeatStartedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_heartbeat_started_get_context)
+    postNotification(
+        type: ServerHeartbeatStartedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_heartbeat_started_get_context
+    )
 }
 
 /// A callback that will be set for "server heartbeat succeeded" events if the user enables server monitoring.
 private func serverHeartbeatSucceeded(_event: OpaquePointer?) {
-    postNotification(type: ServerHeartbeatSucceededEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_heartbeat_succeeded_get_context)
+    postNotification(
+        type: ServerHeartbeatSucceededEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_heartbeat_succeeded_get_context
+    )
 }
 
 /// A callback that will be set for "server heartbeat failed" events if the user enables server monitoring.
 private func serverHeartbeatFailed(_event: OpaquePointer?) {
-    postNotification(type: ServerHeartbeatFailedEvent.self,
-                     _event: _event,
-                     contextFunc: mongoc_apm_server_heartbeat_failed_get_context)
+    postNotification(
+        type: ServerHeartbeatFailedEvent.self,
+        _event: _event,
+        contextFunc: mongoc_apm_server_heartbeat_failed_get_context
+    )
 }
 
 /// Posts a Notification with the specified name, containing an event of type T generated using the provided _event
 /// and context function.
-private func postNotification<T: MongoEvent>(type: T.Type,
-                                             _event: OpaquePointer?,
-                                             contextFunc: (OpaquePointer) -> UnsafeMutableRawPointer?
-                                            ) where T: InitializableFromOpaquePointer {
+private func postNotification<T: MongoEvent>(
+    type: T.Type,
+    _event: OpaquePointer?,
+    contextFunc: (OpaquePointer) -> UnsafeMutableRawPointer?
+) where T: InitializableFromOpaquePointer {
     guard let event = _event else {
         fatalError("Missing event pointer for \(type)")
     }
 
     let eventStruct = type.init(event)
 
-    // TODO SWIFT-524: remove workaround for CDRIVER-3256
+    // TODO: SWIFT-524: remove workaround for CDRIVER-3256
     if let tdChanged = eventStruct as? TopologyDescriptionChangedEvent,
-            tdChanged.previousDescription == tdChanged.newDescription {
+        tdChanged.previousDescription == tdChanged.newDescription {
         return
     }
 
     if let sdChanged = eventStruct as? ServerDescriptionChangedEvent,
-            sdChanged.previousDescription == sdChanged.newDescription {
+        sdChanged.previousDescription == sdChanged.newDescription {
         return
     }