fix: let Ctrl+D pass through as EOF on Windows/Linux (#599)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/renderer/src/components/settings/ShortcutsPane.tsx

@@ -36,7 +36,7 @@ const SHORTCUT_GROUP_DEFINITIONS: ShortcutGroupDefinition[] = [
       {
         action: 'Switch worktree',
         searchKeywords: ['shortcut', 'global', 'worktree', 'switch', 'jump'],
-        keys: ({ mod, shift }) => mod === '⌘' ? [mod, 'J'] : [mod, shift, 'J']
+        keys: ({ mod, shift }) => (mod === '⌘' ? [mod, 'J'] : [mod, shift, 'J'])
       },
       {
         action: 'Create worktree',
@@ -131,12 +131,16 @@ const SHORTCUT_GROUP_DEFINITIONS: ShortcutGroupDefinition[] = [
       {
         action: 'Split pane right',
         searchKeywords: ['shortcut', 'pane', 'split'],
-        keys: ({ mod }) => [mod, 'D']
+        // Why: on Windows/Linux, Ctrl+D must pass through as EOF (#586),
+        // so split-right requires Shift on non-Mac platforms.
+        keys: ({ mod, shift }) => (mod === '⌘' ? [mod, 'D'] : [mod, shift, 'D'])
       },
       {
         action: 'Split pane down',
         searchKeywords: ['shortcut', 'pane', 'split'],
-        keys: ({ mod, shift }) => [mod, shift, 'D']
+        // Why: on Windows/Linux, Ctrl+Shift+D is taken by split-right (#586),
+        // so split-down uses Alt+Shift+D following Windows Terminal convention.
+        keys: ({ mod, shift }) => (mod === '⌘' ? [mod, shift, 'D'] : ['Alt', shift, 'D'])
       },
       {
         action: 'Close pane (EOF)',

src/renderer/src/components/terminal-pane/TerminalContextMenu.tsx

@@ -105,12 +105,16 @@ export default function TerminalContextMenu({
         <DropdownMenuItem onSelect={onSplitRight}>
           <PanelRightOpen />
           Split Right
-          <DropdownMenuShortcut>{mod}D</DropdownMenuShortcut>
+          {/* Why: on Windows/Linux, Ctrl+D must pass through as EOF (#586),
+              so split-right requires Shift on non-Mac platforms. */}
+          <DropdownMenuShortcut>{isMac ? `${mod}D` : `${mod}${shift}D`}</DropdownMenuShortcut>
         </DropdownMenuItem>
         <DropdownMenuItem onSelect={onSplitDown}>
           <PanelBottomOpen />
           Split Down
-          <DropdownMenuShortcut>{`${mod}${shift}D`}</DropdownMenuShortcut>
+          {/* Why: on Windows/Linux, Alt+Shift+D is used for split-down because
+              Ctrl+Shift+D is taken by split-right (#586). */}
+          <DropdownMenuShortcut>{isMac ? `${mod}${shift}D` : `Alt+${shift}D`}</DropdownMenuShortcut>
         </DropdownMenuItem>
         {canExpandPane && (
           <DropdownMenuItem onSelect={onToggleExpand}>

src/renderer/src/components/terminal-pane/terminal-shortcut-policy.test.ts

@@ -106,4 +106,53 @@ describe('resolveTerminalShortcutAction', () => {
       resolveTerminalShortcutAction(event({ key: 'r', code: 'KeyR', ctrlKey: true }), false)
     ).toBeNull()
   })
+
+  it('lets Ctrl+D pass through as EOF on non-Mac, requires Shift for split (#586)', () => {
+    // Ctrl+D without Shift on Windows/Linux must NOT trigger split — it's EOF
+    expect(
+      resolveTerminalShortcutAction(event({ key: 'd', code: 'KeyD', ctrlKey: true }), false)
+    ).toBeNull()
+
+    // Ctrl+Shift+D on Windows/Linux splits the pane right (vertical)
+    expect(
+      resolveTerminalShortcutAction(
+        event({ key: 'd', code: 'KeyD', ctrlKey: true, shiftKey: true }),
+        false
+      )
+    ).toEqual({ type: 'splitActivePane', direction: 'vertical' })
+
+    // Alt+Shift+D on Windows/Linux splits the pane down (horizontal)
+    expect(
+      resolveTerminalShortcutAction(
+        event({ key: 'd', code: 'KeyD', altKey: true, shiftKey: true }),
+        false
+      )
+    ).toEqual({ type: 'splitActivePane', direction: 'horizontal' })
+
+    // Alt+Shift+D should NOT trigger split-down on Mac (Mac uses Cmd+Shift+D)
+    expect(
+      resolveTerminalShortcutAction(
+        event({ key: 'd', code: 'KeyD', altKey: true, shiftKey: true }),
+        true
+      )
+    ).toBeNull()
+
+    // Alt+D (no Shift) on Windows/Linux must pass through for readline forward-word-delete
+    expect(
+      resolveTerminalShortcutAction(event({ key: 'd', code: 'KeyD', altKey: true }), false)
+    ).toBeNull()
+  })
+
+  it('keeps Cmd+D and Cmd+Shift+D for split on macOS', () => {
+    expect(
+      resolveTerminalShortcutAction(event({ key: 'd', code: 'KeyD', metaKey: true }), true)
+    ).toEqual({ type: 'splitActivePane', direction: 'vertical' })
+
+    expect(
+      resolveTerminalShortcutAction(
+        event({ key: 'd', code: 'KeyD', metaKey: true, shiftKey: true }),
+        true
+      )
+    ).toEqual({ type: 'splitActivePane', direction: 'horizontal' })
+  })
 })

src/renderer/src/components/terminal-pane/terminal-shortcut-policy.ts

@@ -58,13 +58,39 @@ export function resolveTerminalShortcutAction(
     }
 
     if (lowerKey === 'd') {
-      return {
-        type: 'splitActivePane',
-        direction: event.shiftKey ? 'horizontal' : 'vertical'
+      if (isMac) {
+        return {
+          type: 'splitActivePane',
+          direction: event.shiftKey ? 'horizontal' : 'vertical'
+        }
       }
+      // Why: on Windows/Linux, Ctrl+D is the standard EOF signal for terminals.
+      // Binding Ctrl+D to split-pane would swallow EOF and break shell workflows
+      // (see #586). Only Ctrl+Shift+D triggers split on non-Mac platforms;
+      // Ctrl+D (without Shift) falls through to the terminal as normal input.
+      if (event.shiftKey) {
+        return { type: 'splitActivePane', direction: 'vertical' }
+      }
+      return null
     }
   }
 
+  // Why: on Windows/Linux, Alt+Shift+D splits the pane down (horizontal).
+  // This lives outside the mod+!alt block above because it uses Alt instead
+  // of Ctrl, following the Windows Terminal convention for split shortcuts
+  // and avoiding the Ctrl+D / EOF conflict (see #586).
+  if (
+    !isMac &&
+    !event.repeat &&
+    !event.metaKey &&
+    !event.ctrlKey &&
+    event.altKey &&
+    event.shiftKey &&
+    event.key.toLowerCase() === 'd'
+  ) {
+    return { type: 'splitActivePane', direction: 'horizontal' }
+  }
+
   if (
     !event.metaKey &&
     !event.ctrlKey &&