Investigate split window blank (#3386)

Sources/Workspace.swift

@@ -10107,6 +10107,93 @@ final class Workspace: Identifiable, ObservableObject {
         return nil
     }
 
+    // Single terminal split lifecycle entry point: every TerminalPanel that enters a
+    // newly assigned split pane must publish its model event and start the layout
+    // follow-up here so portal attachment, Ghostty geometry, and focus converge together.
+    private func beginTerminalSplitPaneLifecycle(
+        newPaneId: PaneID,
+        sourcePaneId: PaneID,
+        orientation: SplitOrientation,
+        panelId: UUID,
+        origin: String,
+        focused: Bool,
+        layoutReason: String,
+        terminalFocusPanelId: UUID?
+    ) {
+        publishCmuxSplitCreated(
+            newPaneId,
+            sourcePaneId: sourcePaneId,
+            orientation: orientation,
+            surfaceId: panelId,
+            kind: "terminal",
+            origin: origin,
+            focused: focused
+        )
+        // Brand-new terminal split panes must enter the shared layout follow-up here so
+        // their portal attachment, Ghostty geometry, and optional focus converge together.
+        beginEventDrivenLayoutFollowUp(
+            reason: layoutReason,
+            terminalFocusPanelId: terminalFocusPanelId,
+            includeGeometry: true
+        )
+    }
+
+    private func beginTerminalSplitSurfaceLifecycle(
+        panelId: UUID,
+        paneId: PaneID,
+        origin: String,
+        focused: Bool,
+        layoutReason: String,
+        terminalFocusPanelId: UUID?
+    ) {
+        publishCmuxSurfaceCreated(
+            panelId,
+            paneId: paneId,
+            kind: "terminal",
+            origin: origin,
+            focused: focused
+        )
+        beginEventDrivenLayoutFollowUp(
+            reason: layoutReason,
+            terminalFocusPanelId: terminalFocusPanelId,
+            includeGeometry: true
+        )
+    }
+
+    private func commitNewTerminalSplitPane(
+        sourcePaneId: PaneID,
+        orientation: SplitOrientation,
+        newTab: Bonsplit.Tab,
+        panelId: UUID,
+        insertFirst: Bool,
+        initialDividerPosition: CGFloat? = nil,
+        origin: String,
+        focused: Bool,
+        layoutReason: String,
+        terminalFocusPanelId: UUID?
+    ) -> PaneID? {
+        guard let newPaneId = bonsplitController.splitPane(
+            sourcePaneId,
+            orientation: orientation,
+            withTab: newTab,
+            insertFirst: insertFirst
+        ) else {
+            return nil
+        }
+        applyInitialSplitDividerPosition(initialDividerPosition, sourcePaneId: sourcePaneId, newPaneId: newPaneId)
+        beginTerminalSplitPaneLifecycle(
+            newPaneId: newPaneId,
+            sourcePaneId: sourcePaneId,
+            orientation: orientation,
+            panelId: panelId,
+            origin: origin,
+            focused: focused,
+            layoutReason: layoutReason,
+            terminalFocusPanelId: terminalFocusPanelId
+        )
+        return newPaneId
+    }
+
     /// Create a new split with a terminal panel
     @discardableResult
     func newTerminalSplit(
@@ -10233,7 +10320,18 @@ final class Workspace: Identifiable, ObservableObject {
         // Create the split with the new tab already present in the new pane.
         isProgrammaticSplit = true
         defer { isProgrammaticSplit = false }
-        guard let newPaneId = bonsplitController.splitPane(paneId, orientation: orientation, withTab: newTab, insertFirst: insertFirst) else {
+        guard commitNewTerminalSplitPane(
+            sourcePaneId: paneId,
+            orientation: orientation,
+            newTab: newTab,
+            panelId: newPanel.id,
+            insertFirst: insertFirst,
+            initialDividerPosition: initialDividerPosition,
+            origin: "terminal_split",
+            focused: focus,
+            layoutReason: "terminal.split",
+            terminalFocusPanelId: focus ? newPanel.id : nil
+        ) != nil else {
             panels.removeValue(forKey: newPanel.id)
             panelTitles.removeValue(forKey: newPanel.id)
             surfaceIdToPanelId.removeValue(forKey: newTab.id)
@@ -10243,8 +10341,6 @@ final class Workspace: Identifiable, ObservableObject {
             terminalInheritanceFontPointsByPanelId.removeValue(forKey: newPanel.id)
             return nil
         }
-        applyInitialSplitDividerPosition(initialDividerPosition, sourcePaneId: paneId, newPaneId: newPaneId)
-        publishCmuxSplitCreated(newPaneId, sourcePaneId: paneId, orientation: orientation, surfaceId: newPanel.id, kind: "terminal", origin: "terminal_split", focused: focus)
 
 #if DEBUG
         cmuxDebugLog("split.created pane=\(paneId.id.uuidString.prefix(5)) orientation=\(orientation)")
@@ -13283,7 +13379,17 @@ final class Workspace: Identifiable, ObservableObject {
 
         isProgrammaticSplit = true
         defer { isProgrammaticSplit = false }
-        guard let newPaneId = bonsplitController.splitPane(paneId, orientation: orientation, withTab: newTab, insertFirst: insertFirst) else {
+        guard commitNewTerminalSplitPane(
+            sourcePaneId: paneId,
+            orientation: orientation,
+            newTab: newTab,
+            panelId: newPanel.id,
+            insertFirst: insertFirst,
+            origin: "terminal_split",
+            focused: true,
+            layoutReason: "terminal.splitPaneWithNewTerminal",
+            terminalFocusPanelId: newPanel.id
+        ) != nil else {
             panels.removeValue(forKey: newPanel.id)
             panelTitles.removeValue(forKey: newPanel.id)
             surfaceIdToPanelId.removeValue(forKey: newTab.id)
@@ -13293,7 +13399,6 @@ final class Workspace: Identifiable, ObservableObject {
             terminalInheritanceFontPointsByPanelId.removeValue(forKey: newPanel.id)
             return nil
         }
-        publishCmuxSplitCreated(newPaneId, sourcePaneId: paneId, orientation: orientation, surfaceId: newPanel.id, kind: "terminal", origin: "terminal_split", focused: true)
 
         bonsplitController.selectTab(newTab.id)
         newPanel.focus()
@@ -14406,7 +14511,14 @@ extension Workspace: BonsplitDelegate {
                         isLoading: false,
                         isPinned: false
                     )
-                    publishCmuxSurfaceCreated(replacementPanel.id, paneId: originalPane, kind: "terminal", origin: "placeholder_repair", focused: false)
+                    beginTerminalSplitSurfaceLifecycle(
+                        panelId: replacementPanel.id,
+                        paneId: originalPane,
+                        origin: "placeholder_repair",
+                        focused: false,
+                        layoutReason: "terminal.placeholderRepair",
+                        terminalFocusPanelId: nil
+                    )
 
                     for extraPlaceholder in placeholderTabs.dropFirst() {
                         bonsplitController.closeTab(extraPlaceholder.id)
@@ -14418,7 +14530,12 @@ extension Workspace: BonsplitDelegate {
                         "fallback=createTerminalAndDropPlaceholders"
                     )
 #endif
-                    _ = newTerminalSurface(inPane: originalPane, focus: false)
+                    if newTerminalSurface(inPane: originalPane, focus: false) != nil {
+                        beginEventDrivenLayoutFollowUp(
+                            reason: "terminal.placeholderRepairFallback",
+                            includeGeometry: true
+                        )
+                    }
                     for tab in controller.tabs(inPane: originalPane) {
                         if panelIdFromSurfaceId(tab.id) == nil {
                             bonsplitController.closeTab(tab.id)
@@ -14477,7 +14594,16 @@ extension Workspace: BonsplitDelegate {
 
         surfaceIdToPanelId[newTabId] = newPanel.id
         normalizePinnedTabs(in: newPane)
-        publishCmuxSplitCreated(newPane, sourcePaneId: originalPane, orientation: orientation, surfaceId: newPanel.id, kind: "terminal", origin: "ui_split", focused: true)
+        beginTerminalSplitPaneLifecycle(
+            newPaneId: newPane,
+            sourcePaneId: originalPane,
+            orientation: orientation,
+            panelId: newPanel.id,
+            origin: "ui_split",
+            focused: true,
+            layoutReason: "terminal.uiSplit",
+            terminalFocusPanelId: newPanel.id
+        )
 #if DEBUG
         cmuxDebugLog(
             "split.didSplit.autoCreate.done pane=\(newPane.id.uuidString.prefix(5)) " +
@@ -14492,7 +14618,6 @@ extension Workspace: BonsplitDelegate {
             if self.bonsplitController.focusedPaneId == newPane {
                 self.bonsplitController.selectTab(newTabId)
             }
-            self.scheduleTerminalGeometryReconcile()
             self.scheduleFocusReconcile()
         }
     }

cmux.xcodeproj/project.pbxproj

@@ -44,6 +44,7 @@
 		C0DE31390000000000000101 /* CMUXOpenCommandTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE31390000000000000102 /* CMUXOpenCommandTests.swift */; };
 		C0DE31390000000000000105 /* CMUXCLIErrorOutputRegressionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE31390000000000000106 /* CMUXCLIErrorOutputRegressionTests.swift */; };
 		C0DE31390000000000000103 /* FilePreviewReviewFeedbackTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE31390000000000000104 /* FilePreviewReviewFeedbackTests.swift */; };
+		C33860010000000000000001 /* TerminalControllerSurfaceSplitOffTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C33860010000000000000002 /* TerminalControllerSurfaceSplitOffTests.swift */; };
 		D3664002D3664002D3664002 /* MarkdownPanelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D3664001D3664001D3664001 /* MarkdownPanelTests.swift */; };
 		C0DEF0A10000000000000001 /* CmuxConfigUI.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DEF0A10000000000000002 /* CmuxConfigUI.swift */; };
 		C0DEF0A30000000000000001 /* SidebarPortDisplayText.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DEF0A30000000000000002 /* SidebarPortDisplayText.swift */; };
@@ -595,6 +596,7 @@
 		43430FA5929121E2EAAB3091 /* AuthEnvironment.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = AuthEnvironment.swift; sourceTree = "<group>"; };
 		C3677001000000000000002 /* CmuxSSHURLRequestTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CmuxSSHURLRequestTests.swift; sourceTree = "<group>"; };
 		491751CE2321474474F27DCF /* TerminalControllerSocketSecurityTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalControllerSocketSecurityTests.swift; sourceTree = "<group>"; };
+		C33860010000000000000002 /* TerminalControllerSurfaceSplitOffTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TerminalControllerSurfaceSplitOffTests.swift; sourceTree = "<group>"; };
 		51D800000000000000000002 /* SidebarIdentifierFormattingTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SidebarIdentifierFormattingTests.swift; sourceTree = "<group>"; };
 		D7AB34300000000000000006 /* SidebarWorkspaceDropPlannerTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SidebarWorkspaceDropPlannerTests.swift; sourceTree = "<group>"; };
 		D7AB34400000000000000004 /* GhosttyTerminalViewVisibilityPolicyTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GhosttyTerminalViewVisibilityPolicyTests.swift; sourceTree = "<group>"; };
@@ -1601,6 +1603,7 @@
 				D7AB34300000000000000006 /* SidebarWorkspaceDropPlannerTests.swift */,
 				C3677001000000000000002 /* CmuxSSHURLRequestTests.swift */,
 				491751CE2321474474F27DCF /* TerminalControllerSocketSecurityTests.swift */,
+				C33860010000000000000002 /* TerminalControllerSurfaceSplitOffTests.swift */,
 				9C1BEA3D2E6F49709A71C021 /* TerminalControllerSocketWriteTests.swift */,
 				E7E000000000000000000004 /* CmuxEventBusTests.swift */,
 				A5A5A504A1B2C3D4E5F60718 /* TerminalNotificationQueueTests.swift */,
@@ -2376,6 +2379,7 @@
 				D7AB34300000000000000005 /* SidebarWorkspaceDropPlannerTests.swift in Sources */,
 				C3677001000000000000001 /* CmuxSSHURLRequestTests.swift in Sources */,
 				8C4BBF2DEF6DF93F395A9EE7 /* TerminalControllerSocketSecurityTests.swift in Sources */,
+				C33860010000000000000001 /* TerminalControllerSurfaceSplitOffTests.swift in Sources */,
 				9C1BEA3D2E6F49709A71C020 /* TerminalControllerSocketWriteTests.swift in Sources */,
 				E7E000000000000000000003 /* CmuxEventBusTests.swift in Sources */,
 				A5A5A503A1B2C3D4E5F60718 /* TerminalNotificationQueueTests.swift in Sources */,

cmuxTests/TerminalControllerSurfaceSplitOffTests.swift

@@ -0,0 +1,89 @@
+import XCTest
+import AppKit
+
+#if canImport(cmux_DEV)
+@testable import cmux_DEV
+#elseif canImport(cmux)
+@testable import cmux
+#endif
+
+@MainActor
+final class TerminalControllerSurfaceSplitOffTests: XCTestCase {
+    func testSurfaceSplitOffRejectsOnlyTabSourcePane() throws {
+        _ = NSApplication.shared
+        let previousAppDelegate = AppDelegate.shared
+        let app = AppDelegate()
+        defer { AppDelegate.shared = previousAppDelegate }
+
+        let windowId = UUID()
+        let window = makeMainWindow(id: windowId)
+        let manager = TabManager()
+        app.registerMainWindow(
+            window,
+            windowId: windowId,
+            tabManager: manager,
+            sidebarState: SidebarState(),
+            sidebarSelectionState: SidebarSelectionState(),
+            fileExplorerState: FileExplorerState()
+        )
+        TerminalController.shared.setActiveTabManager(manager)
+        defer {
+            TerminalController.shared.setActiveTabManager(nil)
+            app.unregisterMainWindowContextForTesting(windowId: windowId)
+            window.orderOut(nil)
+        }
+
+        let workspace = try XCTUnwrap(manager.selectedWorkspace)
+        let terminalPanel = try XCTUnwrap(workspace.focusedTerminalPanel)
+        let sourcePane = try XCTUnwrap(workspace.paneId(forPanelId: terminalPanel.id))
+        XCTAssertEqual(workspace.bonsplitController.tabs(inPane: sourcePane).count, 1)
+        XCTAssertEqual(workspace.bonsplitController.allPaneIds.count, 1)
+
+        let envelope = try v2Envelope(
+            method: "surface.split_off",
+            params: [
+                "surface_id": terminalPanel.id.uuidString,
+                "direction": "right",
+                "focus": false
+            ]
+        )
+
+        XCTAssertEqual(envelope["ok"] as? Bool, false)
+        let error = try XCTUnwrap(envelope["error"] as? [String: Any])
+        XCTAssertEqual(error["code"] as? String, "invalid_state")
+        let data = try XCTUnwrap(error["data"] as? [String: Any])
+        XCTAssertEqual(data["surface_id"] as? String, terminalPanel.id.uuidString)
+        XCTAssertEqual(data["pane_id"] as? String, sourcePane.id.uuidString)
+        XCTAssertEqual(workspace.bonsplitController.tabs(inPane: sourcePane).count, 1)
+        XCTAssertEqual(workspace.bonsplitController.allPaneIds.count, 1)
+    }
+
+    private func makeMainWindow(id: UUID) -> NSWindow {
+        let window = NSWindow(
+            contentRect: NSRect(x: 0, y: 0, width: 500, height: 320),
+            styleMask: [.titled, .closable],
+            backing: .buffered,
+            defer: false
+        )
+        window.identifier = NSUserInterfaceItemIdentifier("cmux.main.\(id.uuidString)")
+        return window
+    }
+
+    private func v2Envelope(
+        method: String,
+        params: [String: Any],
+        file: StaticString = #filePath,
+        line: UInt = #line
+    ) throws -> [String: Any] {
+        let request: [String: Any] = [
+            "id": method,
+            "method": method,
+            "params": params
+        ]
+        let requestData = try JSONSerialization.data(withJSONObject: request)
+        let requestLine = try XCTUnwrap(String(data: requestData, encoding: .utf8), file: file, line: line)
+        let response = TerminalController.shared.handleSocketLine(requestLine)
+        let responseData = try XCTUnwrap(response.data(using: .utf8), file: file, line: line)
+        return try XCTUnwrap(JSONSerialization.jsonObject(with: responseData) as? [String: Any], file: file, line: line)
+    }
+}