Adopt swift-format for linting and formatting

.github/workflows/test.yml

@@ -14,6 +14,28 @@ concurrency:
   cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
 
 jobs:
+  format:
+    name: swift-format
+    runs-on: macos-26
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@v7
+      - name: Select Xcode
+        # Use the same toolchain as the build jobs so the bundled swift-format
+        # version matches what contributors run locally.
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '^26.0'
+      - name: Lint
+        run: swift format lint --strict --recursive --parallel Sources Tests Example/Example Example/ExampleTests Package.swift
+      - name: Verify formatting
+        run: |
+          set -euo pipefail
+          swift format --in-place --recursive --parallel Sources Tests Example/Example Example/ExampleTests Package.swift
+          # Fail if the formatter produced any change, and surface the diff so
+          # the required fix is obvious from the log.
+          git diff --exit-code
+
   package:
     name: Package tests (iOS Simulator)
     runs-on: macos-26

.swift-format

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "lineLength": 160,
+  "indentation": {
+    "spaces": 4
+  },
+  "maximumBlankLines": 1,
+  "respectsExistingLineBreaks": true,
+  "lineBreakBeforeControlFlowKeywords": false,
+  "lineBreakBeforeEachArgument": false,
+  "prioritizeKeepingFunctionOutputTogether": true
+}

Example/Example/MenuViewController.swift

@@ -1,5 +1,5 @@
-import UIKit
 import SwipeMenuViewController
+import UIKit
 
 /// The example's root screen.
 ///
@@ -10,7 +10,7 @@ final class MenuViewController: SwipeMenuViewController {
 
     private let pageTitles = [
         "Bulbasaur", "Caterpie", "Golem", "Jynx",
-        "Marshtomp", "Salamence", "Riolu", "Araquanid"
+        "Marshtomp", "Salamence", "Riolu", "Araquanid",
     ]
 
     private var settings = SwipeMenuSettings()
@@ -22,9 +22,11 @@ final class MenuViewController: SwipeMenuViewController {
         configuration.image = UIImage(systemName: "gearshape")
         configuration.cornerStyle = .capsule
         configuration.preferredSymbolConfigurationForImage = UIImage.SymbolConfiguration(pointSize: 22, weight: .medium)
-        let button = UIButton(configuration: configuration, primaryAction: UIAction { [weak self] _ in
-            self?.presentOptions()
-        })
+        let button = UIButton(
+            configuration: configuration,
+            primaryAction: UIAction { [weak self] _ in
+                self?.presentOptions()
+            })
         button.accessibilityLabel = "Options"
         button.translatesAutoresizingMaskIntoConstraints = false
         return button
@@ -33,7 +35,9 @@ final class MenuViewController: SwipeMenuViewController {
     private static let settingsButtonDiameter: CGFloat = 56
 
     override func viewDidLoad() {
-        pageTitles.forEach { addChild(PageViewController(title: $0)) }
+        for pageTitle in pageTitles {
+            addChild(PageViewController(title: pageTitle))
+        }
 
         super.viewDidLoad()
 
@@ -62,7 +66,7 @@ final class MenuViewController: SwipeMenuViewController {
             settingsButton.widthAnchor.constraint(equalToConstant: Self.settingsButtonDiameter),
             settingsButton.heightAnchor.constraint(equalToConstant: Self.settingsButtonDiameter),
             settingsButton.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -16),
-            settingsButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -16)
+            settingsButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -16),
         ])
     }
 

Example/Example/OptionsViewController.swift

@@ -79,7 +79,7 @@ final class OptionsViewController: UIViewController {
             adjustWidthRow,
             itemWidthRow,
             makeSliderRow(title: "Tab margin", valueLabel: tabMarginValueLabel, slider: tabMarginSlider),
-            makeToggleRow(title: "Swipe between pages", toggle: contentScrollSwitch)
+            makeToggleRow(title: "Swipe between pages", toggle: contentScrollSwitch),
         ]
 
         let contentStack = UIStackView(arrangedSubviews: rows)
@@ -104,59 +104,66 @@ final class OptionsViewController: UIViewController {
             contentStack.leadingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.leadingAnchor),
             contentStack.trailingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.trailingAnchor),
             contentStack.bottomAnchor.constraint(equalTo: scrollView.contentLayoutGuide.bottomAnchor),
-            contentStack.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor)
+            contentStack.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor),
         ])
     }
 
     // MARK: - Actions
 
     private func setUpActions() {
-        pageCountStepper.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.pageCount = Int(pageCountStepper.value)
-            pageCountValueLabel.text = "\(settings.pageCount)"
-            notifyChange()
-        }, for: .valueChanged)
-
-        styleControl.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.setStyle(styleControl.selectedSegmentIndex == 0 ? .flexible : .segmented)
-            updateControls()
-            notifyChange()
-        }, for: .valueChanged)
-
-        decorationControl.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.tabDecoration = SwipeMenuSettings.TabDecoration.allCases[decorationControl.selectedSegmentIndex]
-            notifyChange()
-        }, for: .valueChanged)
-
-        adjustWidthSwitch.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.adjustsItemWidthToFit = adjustWidthSwitch.isOn
-            updateControls()
-            notifyChange()
-        }, for: .valueChanged)
-
-        itemWidthSlider.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.itemWidth = CGFloat(itemWidthSlider.value)
-            itemWidthValueLabel.text = Self.format(settings.itemWidth)
-        }, for: .valueChanged)
+        pageCountStepper.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.pageCount = Int(pageCountStepper.value)
+                pageCountValueLabel.text = "\(settings.pageCount)"
+                notifyChange()
+            }, for: .valueChanged)
+
+        styleControl.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.setStyle(styleControl.selectedSegmentIndex == 0 ? .flexible : .segmented)
+                updateControls()
+                notifyChange()
+            }, for: .valueChanged)
+
+        decorationControl.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.tabDecoration = SwipeMenuSettings.TabDecoration.allCases[decorationControl.selectedSegmentIndex]
+                notifyChange()
+            }, for: .valueChanged)
+
+        adjustWidthSwitch.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.adjustsItemWidthToFit = adjustWidthSwitch.isOn
+                updateControls()
+                notifyChange()
+            }, for: .valueChanged)
+
+        itemWidthSlider.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.itemWidth = CGFloat(itemWidthSlider.value)
+                itemWidthValueLabel.text = Self.format(settings.itemWidth)
+            }, for: .valueChanged)
         itemWidthSlider.addAction(UIAction { [weak self] _ in self?.notifyChange() }, for: [.touchUpInside, .touchUpOutside])
 
-        tabMarginSlider.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.tabMargin = CGFloat(tabMarginSlider.value)
-            tabMarginValueLabel.text = Self.format(settings.tabMargin)
-        }, for: .valueChanged)
+        tabMarginSlider.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.tabMargin = CGFloat(tabMarginSlider.value)
+                tabMarginValueLabel.text = Self.format(settings.tabMargin)
+            }, for: .valueChanged)
         tabMarginSlider.addAction(UIAction { [weak self] _ in self?.notifyChange() }, for: [.touchUpInside, .touchUpOutside])
 
-        contentScrollSwitch.addAction(UIAction { [weak self] _ in
-            guard let self else { return }
-            settings.isContentScrollEnabled = contentScrollSwitch.isOn
-            notifyChange()
-        }, for: .valueChanged)
+        contentScrollSwitch.addAction(
+            UIAction { [weak self] _ in
+                guard let self else { return }
+                settings.isContentScrollEnabled = contentScrollSwitch.isOn
+                notifyChange()
+            }, for: .valueChanged)
     }
 
     private func reset() {

Example/Example/PageViewController.swift

@@ -35,7 +35,7 @@ final class PageViewController: UIViewController {
             label.centerXAnchor.constraint(equalTo: view.centerXAnchor),
             label.centerYAnchor.constraint(equalTo: view.centerYAnchor),
             label.leadingAnchor.constraint(greaterThanOrEqualTo: view.leadingAnchor, constant: 16),
-            label.trailingAnchor.constraint(lessThanOrEqualTo: view.trailingAnchor, constant: -16)
+            label.trailingAnchor.constraint(lessThanOrEqualTo: view.trailingAnchor, constant: -16),
         ])
     }
 }

Example/Example/SwipeMenuSettings.swift

@@ -1,5 +1,5 @@
-import UIKit
 import SwipeMenuViewController
+import UIKit
 
 /// The user-adjustable configuration behind the example's swipe menu.
 ///

Example/ExampleTests/SwipeMenuSettingsTests.swift

@@ -1,6 +1,7 @@
+import SwipeMenuViewController
 import Testing
 import UIKit
-import SwipeMenuViewController
+
 @testable import Example
 
 @Suite("SwipeMenuSettings")

Package.swift

@@ -22,6 +22,6 @@ let package = Package(
             swiftSettings: [
                 .defaultIsolation(MainActor.self)
             ]
-        )
+        ),
     ]
 )

Sources/SwipeMenuViewController/ContentScrollView.swift

@@ -82,7 +82,9 @@ open class ContentScrollView: UIScrollView {
         guard superview != nil else { return }
         // Discard the previous pages first so a reload replaces them instead of
         // stacking a second set of page views into the hierarchy.
-        pageViews.forEach { $0.removeFromSuperview() }
+        for pageView in pageViews {
+            pageView.removeFromSuperview()
+        }
         pageViews = []
         setup()
     }
@@ -98,7 +100,8 @@ open class ContentScrollView: UIScrollView {
     private func setup() {
 
         guard let dataSource,
-              dataSource.numberOfPages(in: self) > 0 else { return }
+            dataSource.numberOfPages(in: self) > 0
+        else { return }
 
         setupScrollView()
         setupPages()
@@ -141,7 +144,7 @@ open class ContentScrollView: UIScrollView {
                 pageView.topAnchor.constraint(equalTo: self.topAnchor),
                 pageView.widthAnchor.constraint(equalTo: self.widthAnchor),
                 pageView.heightAnchor.constraint(equalTo: self.heightAnchor),
-                pageView.leadingAnchor.constraint(equalTo: leadingAnchor)
+                pageView.leadingAnchor.constraint(equalTo: leadingAnchor),
             ])
         }
     }

Sources/SwipeMenuViewController/SwipeMenuView.swift

@@ -37,10 +37,10 @@ import UIKit
 }
 
 extension SwipeMenuViewDelegate {
-    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewWillSetupAt currentIndex: Int) { }
-    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewDidSetupAt currentIndex: Int) { }
-    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, willChangeIndexFrom fromIndex: Int, to toIndex: Int) { }
-    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, didChangeIndexFrom fromIndex: Int, to toIndex: Int) { }
+    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewWillSetupAt currentIndex: Int) {}
+    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewDidSetupAt currentIndex: Int) {}
+    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, willChangeIndexFrom fromIndex: Int, to toIndex: Int) {}
+    public func swipeMenuView(_ swipeMenuView: SwipeMenuView, didChangeIndexFrom fromIndex: Int, to toIndex: Int) {}
 }
 
 // MARK: - SwipeMenuViewDataSource
@@ -299,7 +299,12 @@ open class SwipeMenuView: UIView {
         tabView = TabView(frame: CGRect(x: 0, y: 0, width: frame.width, height: options.tabView.height), options: options.tabView)
         tabView?.clipsToBounds = options.tabView.clipsToBounds
 
-        contentScrollView = ContentScrollView(frame: CGRect(x: 0, y: options.tabView.height, width: frame.width, height: frame.height - options.tabView.height), default: defaultIndex, options: options.contentScrollView)
+        let contentFrame = CGRect(
+            x: 0,
+            y: options.tabView.height,
+            width: frame.width,
+            height: frame.height - options.tabView.height)
+        contentScrollView = ContentScrollView(frame: contentFrame, default: defaultIndex, options: options.contentScrollView)
         contentScrollView?.clipsToBounds = options.contentScrollView.clipsToBounds
 
         tabView?.update(defaultIndex)
@@ -317,8 +322,8 @@ open class SwipeMenuView: UIView {
             tabView.topAnchor.constraint(equalTo: self.topAnchor),
             tabView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
             tabView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
-            tabView.heightAnchor.constraint(equalToConstant: options.tabView.height)
-            ])
+            tabView.heightAnchor.constraint(equalToConstant: options.tabView.height),
+        ])
     }
 
     private func layout(contentScrollView: ContentScrollView) {
@@ -329,8 +334,8 @@ open class SwipeMenuView: UIView {
             contentScrollView.topAnchor.constraint(equalTo: self.topAnchor, constant: options.tabView.height),
             contentScrollView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
             contentScrollView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
-            contentScrollView.bottomAnchor.constraint(equalTo: self.bottomAnchor)
-            ])
+            contentScrollView.bottomAnchor.constraint(equalTo: self.bottomAnchor),
+        ])
     }
 
     private func reset() {

Sources/SwipeMenuViewController/SwipeMenuViewController.swift

@@ -39,30 +39,31 @@ open class SwipeMenuViewController: UIViewController, SwipeMenuViewDelegate, Swi
         // The top anchor is chosen once from the initial options. Toggling
         // `options.tabView.isSafeAreaEnabled` at runtime does not re-pin the
         // view, so configure the safe area behavior before the view loads.
-        let topAnchor = swipeMenuView.options.tabView.isSafeAreaEnabled
+        let topAnchor =
+            swipeMenuView.options.tabView.isSafeAreaEnabled
             ? view.safeAreaLayoutGuide.topAnchor
             : view.topAnchor
         NSLayoutConstraint.activate([
             swipeMenuView.topAnchor.constraint(equalTo: topAnchor),
             swipeMenuView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
             swipeMenuView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
-            swipeMenuView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
+            swipeMenuView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
         ])
     }
 
     // MARK: - SwipeMenuViewDelegate
 
     /// Called before the swipe menu view sets up its views. The default implementation does nothing; override to react.
-    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewWillSetupAt currentIndex: Int) { }
+    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewWillSetupAt currentIndex: Int) {}
 
     /// Called after the swipe menu view has set up its views. The default implementation does nothing; override to react.
-    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewDidSetupAt currentIndex: Int) { }
+    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewDidSetupAt currentIndex: Int) {}
 
     /// Called before the front page changes. The default implementation does nothing; override to react.
-    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, willChangeIndexFrom fromIndex: Int, to toIndex: Int) { }
+    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, willChangeIndexFrom fromIndex: Int, to toIndex: Int) {}
 
     /// Called after the front page has changed. The default implementation does nothing; override to react.
-    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, didChangeIndexFrom fromIndex: Int, to toIndex: Int) { }
+    open func swipeMenuView(_ swipeMenuView: SwipeMenuView, didChangeIndexFrom fromIndex: Int, to toIndex: Int) {}
 
     // MARK: - SwipeMenuViewDataSource
 
@@ -87,7 +88,11 @@ open class SwipeMenuViewController: UIViewController, SwipeMenuViewDelegate, Swi
     /// than crashing. Override to provide pages that are not backed by `children`.
     open func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewControllerForPageAt index: Int) -> UIViewController {
         guard children.indices.contains(index) else {
-            assertionFailure("SwipeMenuViewController: requested a page at \(index) but only \(children.count) child view controllers exist. Override the data source to provide the missing pages.")
+            assertionFailure(
+                """
+                SwipeMenuViewController: requested a page at \(index) but only \(children.count) \
+                child view controllers exist. Override the data source to provide the missing pages.
+                """)
             // Return a detached placeholder rather than crashing. It is
             // intentionally not added via `addChild(_:)`: the default
             // `numberOfPages(in:)` counts `children`, so adding children on this