fix: fade tab strip edges when tabs overflow

Resources/Localizable.xcstrings

@@ -14944,23 +14944,6 @@
         }
       }
     },
-    "tabBar.autoTitle.pullRequest": {
-      "extractionState": "manual",
-      "localizations": {
-        "en": {
-          "stringUnit": {
-            "state": "translated",
-            "value": "PR #%lld"
-          }
-        },
-        "ja": {
-          "stringUnit": {
-            "state": "translated",
-            "value": "PR #%lld"
-          }
-        }
-      }
-    },
     "tabBar.newTerminalTab": {
       "extractionState": "manual",
       "localizations": {

Sources/WindowPaneChromePortal.swift

@@ -494,7 +494,18 @@ final class WindowPaneChromePortalRegistry: NSObject, BonsplitPaneChromePortalBr
     var hostViewForTesting: NSView { hostView }
 
     func nativeTabFramesForTesting(in paneID: PaneID) -> [NSRect] {
-        bars[paneID]?.tabFramesForTesting ?? []
+        bars[paneID]?.layoutSubtreeIfNeeded()
+        return bars[paneID]?.tabFramesForTesting ?? []
+    }
+
+    func nativeVisibleTabRectForTesting(in paneID: PaneID) -> NSRect {
+        bars[paneID]?.layoutSubtreeIfNeeded()
+        return bars[paneID]?.visibleDocumentRectForTesting ?? .zero
+    }
+
+    func nativeTabDocumentWidthForTesting(in paneID: PaneID) -> CGFloat {
+        bars[paneID]?.layoutSubtreeIfNeeded()
+        return bars[paneID]?.documentWidthForTesting ?? 0
     }
 
     func nativeTabInsertionIndexForTesting(in paneID: PaneID, documentX: CGFloat) -> Int? {
@@ -595,7 +606,9 @@ private final class TabStripScrollView: NSScrollView {
 private final class NativePaneTabBarView: PaneChromeDragBackgroundView {
     private static let tabTransferPasteboardType =
         NSPasteboard.PasteboardType("com.splittabbar.tabtransfer")
+    private static let edgeFadeWidth: CGFloat = 24
     private let scrollView = TabStripScrollView(frame: .zero)
+    private let edgeFadeMask = CAGradientLayer()
     // Unflipped on purpose: a flipped document view mirrors the glass pills'
     // built-in shadow upward (layer geometry flip flips shadowOffset), while
     // the control capsules in the unflipped host cast theirs downward. Layout
@@ -649,6 +662,16 @@ private final class NativePaneTabBarView: PaneChromeDragBackgroundView {
         scrollView.horizontalScrollElasticity = .automatic
         scrollView.verticalScrollElasticity = .none
         scrollView.documentView = documentView
+        scrollView.wantsLayer = true
+        scrollView.contentView.postsBoundsChangedNotifications = true
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(clipBoundsDidChange),
+            name: NSView.boundsDidChangeNotification,
+            object: scrollView.contentView
+        )
+        edgeFadeMask.startPoint = CGPoint(x: 0, y: 0.5)
+        edgeFadeMask.endPoint = CGPoint(x: 1, y: 0.5)
         addSubview(scrollView)
         documentView.addSubview(dropIndicator, positioned: .above, relativeTo: nil)
         registerForDraggedTypes([Self.tabTransferPasteboardType])
@@ -659,6 +682,8 @@ private final class NativePaneTabBarView: PaneChromeDragBackgroundView {
 
     @objc private func newTabPressed() { newTabAction?() }
 
+    @objc private func clipBoundsDidChange(_ note: Notification) { updateEdgeFades() }
+
     required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
 
     override func layout() {
@@ -737,7 +762,9 @@ private final class NativePaneTabBarView: PaneChromeDragBackgroundView {
         newTabButton.frame = NSRect(x: x, y: 0, width: plusWidth, height: height)
         x += plusWidth + gap
         documentView.frame = NSRect(x: 0, y: 0, width: max(x, scrollView.contentSize.width), height: height)
+        constrainClipOrigin()
         revealPendingTab()
+        updateEdgeFades()
         if let dropIndicatorIndex {
             positionDropIndicator(at: dropIndicatorIndex)
         }
@@ -758,6 +785,43 @@ private final class NativePaneTabBarView: PaneChromeDragBackgroundView {
         scrollView.reflectScrolledClipView(clip)
     }
 
+    /// Closing tabs shrinks the document under a scrolled clip view; pull the
+    /// origin back inside the new bounds.
+    private func constrainClipOrigin() {
+        let clip = scrollView.contentView
+        let constrained = clip.constrainBoundsRect(clip.bounds).origin
+        guard constrained.x != clip.bounds.origin.x else { return }
+        clip.setBoundsOrigin(NSPoint(x: constrained.x, y: 0))
+        scrollView.reflectScrolledClipView(clip)
+    }
+
+    /// Fades the edge that has hidden tabs. The mask exists only while the row
+    /// overflows so a row that fits renders exactly as before.
+    private func updateEdgeFades() {
+        let bounds = scrollView.contentView.bounds
+        let hasLeading = bounds.minX > 0.5
+        let hasTrailing = bounds.maxX < documentView.frame.width - 0.5
+        let width = scrollView.bounds.width
+        CATransaction.begin()
+        CATransaction.setDisableActions(true)
+        defer { CATransaction.commit() }
+        guard hasLeading || hasTrailing, width > Self.edgeFadeWidth * 2 else {
+            scrollView.layer?.mask = nil
+            return
+        }
+        let fraction = Self.edgeFadeWidth / width
+        let opaque = NSColor.black.cgColor
+        let clear = NSColor.clear.cgColor
+        edgeFadeMask.frame = scrollView.bounds
+        edgeFadeMask.colors = [hasLeading ? clear : opaque, opaque, opaque, hasTrailing ? clear : opaque]
+        edgeFadeMask.locations = [0, fraction, 1 - fraction, 1].map { NSNumber(value: Double($0)) }
+        scrollView.layer?.mask = edgeFadeMask
+    }
+
+    fileprivate var visibleDocumentRectForTesting: NSRect { scrollView.contentView.bounds }
+
+    fileprivate var documentWidthForTesting: CGFloat { documentView.frame.width }
+
     fileprivate var tabFramesForTesting: [NSRect] {
         guard let descriptor else { return [] }
         return descriptor.tabs.compactMap { pillViews[$0.id]?.frame }

Sources/Workspace.swift

@@ -831,39 +831,9 @@ final class Workspace: Identifiable, ObservableObject {
            !custom.isEmpty {
             return custom
         }
-        if let pullRequest = panelPullRequests[panelId] {
-            let panelBranch = normalizedSidebarBranchName(panelGitBranches[panelId]?.branch)
-            let pullRequestBranch = normalizedSidebarBranchName(pullRequest.branch)
-            if pullRequestBranch == nil || panelBranch == pullRequestBranch {
-                return String(
-                    localized: "tabBar.autoTitle.pullRequest",
-                    defaultValue: "PR #\(pullRequest.number)"
-                )
-            }
-        }
-        if let branch = normalizedSidebarBranchName(panelGitBranches[panelId]?.branch) {
-            return Self.ticketIdentifier(in: branch) ?? branch
-        }
         return fallbackTitle
     }
 
-    private static let ticketIdentifierPattern = try? NSRegularExpression(
-        pattern: #"(?<![A-Za-z0-9])([A-Z][A-Z0-9]+-[0-9]+)(?![A-Za-z0-9])"#
-    )
-
-    private static func ticketIdentifier(in branch: String) -> String? {
-        guard let ticketIdentifierPattern,
-              let match = ticketIdentifierPattern.firstMatch(
-                  in: branch,
-                  range: NSRange(branch.startIndex..., in: branch)
-              ),
-              match.numberOfRanges > 1,
-              let range = Range(match.range(at: 1), in: branch) else {
-            return nil
-        }
-        return String(branch[range])
-    }
-
     func syncResolvedPanelTitle(panelId: UUID) {
         guard let panel = panels[panelId], let tabId = surfaceIdFromPanelId(panelId) else { return }
         let baseTitle = panelTitles[panelId] ?? panel.displayTitle

programaTests/WindowAndDragTests.swift

@@ -209,6 +209,73 @@ final class WindowGlassEffectTests: XCTestCase {
         throw XCTSkip("Native Liquid Glass requires the macOS 26 SDK and runtime")
     }
 
+    func testNativePaneTabBarKeepsTitlesReadableAndScrollsSelectedTabIntoView() throws {
+        #if compiler(>=6.2)
+        if #available(macOS 26.0, *) {
+            _ = NSApplication.shared
+            let root = NSView(frame: NSRect(x: 0, y: 0, width: 360, height: 320))
+            let terminalHost = WindowTerminalHostView(frame: root.bounds)
+            let anchor = NSView(frame: NSRect(x: 20, y: 270, width: 300, height: 40))
+            root.addSubview(anchor)
+            root.addSubview(terminalHost, positioned: .above, relativeTo: anchor)
+            let window = NSWindow(
+                contentRect: root.bounds,
+                styleMask: [.titled, .closable, .resizable],
+                backing: .buffered,
+                defer: false
+            )
+            defer { window.orderOut(nil) }
+            window.contentView = root
+
+            let bridge = WindowPaneChromePortalRegistry.bridge(for: window)
+            let paneID = PaneID()
+            let ids = (0..<15).map { _ in TabID() }
+            func publish(selected: Int) {
+                let tabs = ids.enumerated().map { index, id in
+                    BonsplitPaneChromeTabDescriptor(
+                        id: id, title: "A long terminal title number \(index)", icon: "terminal",
+                        iconImageData: nil, isSelected: index == selected, isPinned: false,
+                        isDirty: false, showsNotificationBadge: false, accessibilityValue: "",
+                        menuItems: []
+                    )
+                }
+                bridge.updatePaneChrome(BonsplitPaneChromeDescriptor(
+                    paneID: paneID, anchorView: anchor, tabs: tabs, isFocused: true,
+                    isVisible: true, leadingInset: 0, showsSplitButtons: false,
+                    onSelect: { _ in }, onClose: { _ in }, onContextAction: { _, _ in },
+                    dragPasteboardData: { _ in nil }, onDragStateChanged: { _, _ in },
+                    validatedDropIndex: { (0...tabs.count).contains($0) ? $0 : nil },
+                    onDropTab: { _ in true },
+                    onNewTab: {}, onSplitRight: {}, onSplitDown: {}
+                ))
+                root.layoutSubtreeIfNeeded()
+            }
+
+            publish(selected: 0)
+            let readableMinimumWidth: CGFloat = 78
+            let frames = bridge.nativeTabFramesForTesting(in: paneID)
+            XCTAssertEqual(frames.count, ids.count)
+            for frame in frames {
+                XCTAssertGreaterThanOrEqual(frame.width, readableMinimumWidth)
+            }
+            let visible = bridge.nativeVisibleTabRectForTesting(in: paneID)
+            XCTAssertGreaterThan(visible.width, 0)
+            XCTAssertGreaterThan(bridge.nativeTabDocumentWidthForTesting(in: paneID), visible.width)
+            XCTAssertLessThanOrEqual(try XCTUnwrap(frames.first).minX, visible.minX + 0.5)
+
+            publish(selected: ids.count - 1)
+            let scrolledVisible = bridge.nativeVisibleTabRectForTesting(in: paneID)
+            let lastFrame = try XCTUnwrap(bridge.nativeTabFramesForTesting(in: paneID).last)
+            XCTAssertGreaterThan(scrolledVisible.minX, 0)
+            XCTAssertGreaterThanOrEqual(lastFrame.minX, scrolledVisible.minX)
+            XCTAssertLessThanOrEqual(lastFrame.maxX, scrolledVisible.maxX)
+            return
+        }
+        #endif
+
+        throw XCTSkip("Native Liquid Glass requires the macOS 26 SDK and runtime")
+    }
+
     func testNativePaneTabInsertionIndicatorStaysInsideDocumentBounds() throws {
         #if compiler(>=6.2)
         let bounds = NSRect(x: 0, y: 0, width: 240, height: 28)