Move Pane to Tab (GH7075) (#10780)

<!-- Enter a brief description/summary of your PR here. What does it fix/what does it change/how was it tested (even manually, if necessary)? -->
## Summary of the Pull Request
Add functionality to move a pane to another tab. If the tab index is greater than the number of current tabs a new tab will be created with the pane as its root. Similarly, if the last pane on a tab is moved to another tab, the original tab will be closed.

This is largely complete, but I know that I'm messing around with things that I am unfamiliar with, and would like to avoid footguns where possible. 

<!-- Other than the issue solved, is this relevant to any other issues/existing PRs? --> 
## References
#4587 

<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist
* [x] Closes #7075
* [x] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] Tests added/passed
* [x] Documentation updated. If checked, please file a pull request on [our docs repo](https://github.com/MicrosoftDocs/terminal) and link it here: #xxx
* [x] Schema updated.
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

<!-- Provide a more detailed description of the PR, other things fixed or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments
Things done:
- Moving a pane to a new tab appears to work. Moving a pane to an existing tab mostly works. Moving a pane back to its original tab appears to work.
- Set up {Attach,Detach}Pane methods to add or remove a pane from a pane. Detach is slightly different than Close in that we want to persist the tree structure and terminal controls.
- Add `Detached` event on a pane that can be subscribed to to remove other event handlers if desired. 
- Added simple WalkTree abstraction for one-off recursion use cases that calls a provided function on each pane in order (and optionally terminates early).
- Fixed an in-prod bug with closing panes. Specifically, if you have a tree (1; 2 3) and close the 1 pane, then 3 will lose its borders because of these lines clearing the border on both children https://github.com/microsoft/terminal/blob/main/src/cascadia/TerminalApp/Pane.cpp#L1197-L1201 .

To do:
- Right now I have `TerminalTab` as a friend class of `Pane` so I can access some extra properties in my `WalkTree` callbacks, but there is probably a better choice for the abstraction boundary.

Next Steps:
- In a future PR Drag & Drop handlers could be added that utilize the Attach/Detach infrastructure to provide a better UI.
- Similarly once this is working, it should be possible to convert an entire tab into a pane on an existing tab (Tab::DetachRoot on original tab followed by Tab::AttachPane on the target tab).
- Its been 10 years, I just really want to use concepts already.

<!-- Describe how you validated the behavior. Add automated tests wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
Manual testing by creating pane(s), and moving them between tabs and creating new tabs and destroying tabs by moving the last remaining pane.

.github/actions/spelling/allow/apis.txt

@@ -79,6 +79,7 @@ localtime
 lround
 LSHIFT
 memicmp
+mptt
 mov
 msappx
 MULTIPLEUSE

doc/cascadia/profiles.schema.json

@@ -239,6 +239,7 @@
         "identifyWindows",
         "moveFocus",
         "movePane",
+        "swapPane",
         "moveTab",
         "newTab",
         "newWindow",
@@ -493,6 +494,23 @@
               "type": "integer",
               "default": 0,
               "description": "Which tab to switch to, with the first being 0"
+          }
+        }
+      }
+    ],
+    "required": [ "index" ]
+  },
+  "MovePaneAction": {
+      "description": "Arguments corresponding to a Move Pane Action",
+      "allOf": [
+        { "$ref": "#/definitions/ShortcutAction" },
+        {
+          "properties": {
+            "action": { "type": "string", "pattern": "movePane" },
+            "index": {
+              "type": "integer",
+              "default": 0,
+              "description": "Which tab to move the pane to, with the first being 0"
             }
           }
         }
@@ -516,13 +534,13 @@
       ],
       "required": [ "direction" ]
     },
-    "MovePaneAction": {
-      "description": "Arguments corresponding to a Move Pane Action",
+    "SwapPaneAction": {
+      "description": "Arguments corresponding to a Swap Pane Action",
       "allOf": [
         { "$ref": "#/definitions/ShortcutAction" },
         {
           "properties": {
-            "action": { "type": "string", "pattern": "movePane" },
+            "action": { "type": "string", "pattern": "swapPane" },
             "direction": {
               "$ref": "#/definitions/FocusDirection",
               "default": "left",
@@ -972,6 +990,7 @@
               { "$ref": "#/definitions/SwitchToTabAction" },
               { "$ref": "#/definitions/MoveFocusAction" },
               { "$ref": "#/definitions/MovePaneAction" },
+              { "$ref": "#/definitions/SwapPaneAction" },
               { "$ref": "#/definitions/ResizePaneAction" },
               { "$ref": "#/definitions/SendInputAction" },
               { "$ref": "#/definitions/SplitPaneAction" },

src/cascadia/LocalTests_TerminalApp/CommandlineTest.cpp

@@ -56,7 +56,7 @@ namespace TerminalAppLocalTests
         TEST_METHOD(ParseComboCommandlineIntoArgs);
         TEST_METHOD(ParseFocusTabArgs);
         TEST_METHOD(ParseMoveFocusArgs);
-        TEST_METHOD(ParseMovePaneArgs);
+        TEST_METHOD(ParseSwapPaneArgs);
         TEST_METHOD(ParseArgumentsWithParsingTerminators);
         TEST_METHOD(ParseFocusPaneArgs);
 
@@ -1208,14 +1208,9 @@ namespace TerminalAppLocalTests
         }
     }
 
-    void CommandlineTest::ParseMovePaneArgs()
+    void CommandlineTest::ParseSwapPaneArgs()
     {
-        BEGIN_TEST_METHOD_PROPERTIES()
-            TEST_METHOD_PROPERTY(L"Data:useShortForm", L"{false, true}")
-        END_TEST_METHOD_PROPERTIES()
-
-        INIT_TEST_PROPERTY(bool, useShortForm, L"If true, use `mp` instead of `move-pane`");
-        const wchar_t* subcommand = useShortForm ? L"mp" : L"move-pane";
+        const wchar_t* subcommand = L"swap-pane";
 
         {
             AppCommandlineArgs appArgs{};
@@ -1236,9 +1231,9 @@ namespace TerminalAppLocalTests
             VERIFY_ARE_EQUAL(ShortcutAction::NewTab, appArgs._startupActions.at(0).Action());
 
             auto actionAndArgs = appArgs._startupActions.at(1);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            auto myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            auto myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Left, myArgs.Direction());
         }
@@ -1253,9 +1248,9 @@ namespace TerminalAppLocalTests
             VERIFY_ARE_EQUAL(ShortcutAction::NewTab, appArgs._startupActions.at(0).Action());
 
             auto actionAndArgs = appArgs._startupActions.at(1);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            auto myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            auto myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Right, myArgs.Direction());
         }
@@ -1270,9 +1265,9 @@ namespace TerminalAppLocalTests
             VERIFY_ARE_EQUAL(ShortcutAction::NewTab, appArgs._startupActions.at(0).Action());
 
             auto actionAndArgs = appArgs._startupActions.at(1);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            auto myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            auto myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Up, myArgs.Direction());
         }
@@ -1287,9 +1282,9 @@ namespace TerminalAppLocalTests
             VERIFY_ARE_EQUAL(ShortcutAction::NewTab, appArgs._startupActions.at(0).Action());
 
             auto actionAndArgs = appArgs._startupActions.at(1);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            auto myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            auto myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Down, myArgs.Direction());
         }
@@ -1311,16 +1306,16 @@ namespace TerminalAppLocalTests
             VERIFY_ARE_EQUAL(ShortcutAction::NewTab, appArgs._startupActions.at(0).Action());
 
             auto actionAndArgs = appArgs._startupActions.at(1);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            auto myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            auto myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Left, myArgs.Direction());
 
             actionAndArgs = appArgs._startupActions.at(2);
-            VERIFY_ARE_EQUAL(ShortcutAction::MovePane, actionAndArgs.Action());
+            VERIFY_ARE_EQUAL(ShortcutAction::SwapPane, actionAndArgs.Action());
             VERIFY_IS_NOT_NULL(actionAndArgs.Args());
-            myArgs = actionAndArgs.Args().try_as<MovePaneArgs>();
+            myArgs = actionAndArgs.Args().try_as<SwapPaneArgs>();
             VERIFY_IS_NOT_NULL(myArgs);
             VERIFY_ARE_EQUAL(FocusDirection::Right, myArgs.Direction());
         }

src/cascadia/LocalTests_TerminalApp/TabTests.cpp

@@ -82,7 +82,7 @@ namespace TerminalAppLocalTests
         TEST_METHOD(MoveFocusFromZoomedPane);
         TEST_METHOD(CloseZoomedPane);
 
-        TEST_METHOD(MovePanes);
+        TEST_METHOD(SwapPanes);
 
         TEST_METHOD(NextMRUTab);
         TEST_METHOD(VerifyCommandPaletteTabSwitcherOrder);
@@ -821,7 +821,7 @@ namespace TerminalAppLocalTests
         VERIFY_SUCCEEDED(result);
     }
 
-    void TabTests::MovePanes()
+    void TabTests::SwapPanes()
     {
         auto page = _commonSetup();
 
@@ -914,10 +914,10 @@ namespace TerminalAppLocalTests
         // -------------------
         TestOnUIThread([&]() {
             // Set up action
-            MovePaneArgs args{ FocusDirection::Left };
+            SwapPaneArgs args{ FocusDirection::Left };
             ActionEventArgs eventArgs{ args };
 
-            page->_HandleMovePane(nullptr, eventArgs);
+            page->_HandleSwapPane(nullptr, eventArgs);
         });
 
         Sleep(250);
@@ -945,10 +945,10 @@ namespace TerminalAppLocalTests
         // -------------------
         TestOnUIThread([&]() {
             // Set up action
-            MovePaneArgs args{ FocusDirection::Up };
+            SwapPaneArgs args{ FocusDirection::Up };
             ActionEventArgs eventArgs{ args };
 
-            page->_HandleMovePane(nullptr, eventArgs);
+            page->_HandleSwapPane(nullptr, eventArgs);
         });
 
         Sleep(250);
@@ -976,10 +976,10 @@ namespace TerminalAppLocalTests
         // -------------------
         TestOnUIThread([&]() {
             // Set up action
-            MovePaneArgs args{ FocusDirection::Right };
+            SwapPaneArgs args{ FocusDirection::Right };
             ActionEventArgs eventArgs{ args };
 
-            page->_HandleMovePane(nullptr, eventArgs);
+            page->_HandleSwapPane(nullptr, eventArgs);
         });
 
         Sleep(250);
@@ -1007,10 +1007,10 @@ namespace TerminalAppLocalTests
         // -------------------
         TestOnUIThread([&]() {
             // Set up action
-            MovePaneArgs args{ FocusDirection::Down };
+            SwapPaneArgs args{ FocusDirection::Down };
             ActionEventArgs eventArgs{ args };
 
-            page->_HandleMovePane(nullptr, eventArgs);
+            page->_HandleSwapPane(nullptr, eventArgs);
         });
 
         Sleep(250);

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -143,6 +143,20 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
+    void TerminalPage::_HandleMovePane(const IInspectable& /*sender*/,
+                                       const ActionEventArgs& args)
+    {
+        if (args == nullptr)
+        {
+            args.Handled(false);
+        }
+        else if (const auto& realArgs = args.ActionArgs().try_as<MovePaneArgs>())
+        {
+            auto moved = _MovePane(realArgs.TabIndex());
+            args.Handled(moved);
+        }
+    }
+
     void TerminalPage::_HandleSplitPane(const IInspectable& /*sender*/,
                                         const ActionEventArgs& args)
     {
@@ -323,10 +337,10 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
-    void TerminalPage::_HandleMovePane(const IInspectable& /*sender*/,
+    void TerminalPage::_HandleSwapPane(const IInspectable& /*sender*/,
                                        const ActionEventArgs& args)
     {
-        if (const auto& realArgs = args.ActionArgs().try_as<MovePaneArgs>())
+        if (const auto& realArgs = args.ActionArgs().try_as<SwapPaneArgs>())
         {
             if (realArgs.Direction() == FocusDirection::None)
             {
@@ -335,7 +349,7 @@ namespace winrt::TerminalApp::implementation
             }
             else
             {
-                _MovePane(realArgs.Direction());
+                _SwapPane(realArgs.Direction());
                 args.Handled(true);
             }
         }