Add --appendCommandLine flag for appending to command (#15822)

Added --appendCommandLine flag that when set, appends the command to the
preset command in the profile instead of replacing it.

Previously, there was no good way to launch wt while running a command
appended to the set command in the profile. Some uses include profiles
that are set to login or start an application.

Additional comments: Looking for a review, and expecting additional
changes that needs to be done. For example, I am not really sure on how
to include the the option's information in the CallForHelp() screen.
Also, would be great if someone could guide me on including tests for
this new feature. Thanks!

Closes #5528

---------

Co-authored-by: Charles Liu <hliu729@outlook.com>

src/cascadia/TerminalApp/AppCommandlineArgs.cpp

@@ -568,6 +568,9 @@ void AppCommandlineArgs::_addNewTerminalArgs(AppCommandlineArgs::NewTerminalSubc
     subcommand.colorSchemeOption = subcommand.subcommand->add_option("--colorScheme",
                                                                      _startingColorScheme,
                                                                      RS_A(L"CmdColorSchemeArgDesc"));
+
+    subcommand.appendCommandLineOption = subcommand.subcommand->add_flag("--appendCommandLine", _appendCommandLineOption, RS_A(L"CmdAppendCommandLineDesc"));
+
     // Using positionals_at_end allows us to support "wt new-tab -d wsl -d Ubuntu"
     // without CLI11 thinking that we've specified -d twice.
     // There's an alternate construction where we make all subcommands "prefix commands",
@@ -654,6 +657,10 @@ NewTerminalArgs AppCommandlineArgs::_getNewTerminalArgs(AppCommandlineArgs::NewT
     {
         args.ColorScheme(winrt::to_hstring(_startingColorScheme));
     }
+    if (*subcommand.appendCommandLineOption)
+    {
+        args.AppendCommandLine(_appendCommandLineOption);
+    }
 
     return args;
 }
@@ -699,6 +706,7 @@ void AppCommandlineArgs::_resetStateToDefault()
     _startingTabColor.clear();
     _commandline.clear();
     _suppressApplicationTitle = false;
+    _appendCommandLineOption = false;
 
     _splitVertical = false;
     _splitHorizontal = false;

src/cascadia/TerminalApp/AppCommandlineArgs.h

@@ -67,6 +67,7 @@ class TerminalApp::AppCommandlineArgs final
         CLI::Option* tabColorOption;
         CLI::Option* suppressApplicationTitleOption;
         CLI::Option* colorSchemeOption;
+        CLI::Option* appendCommandLineOption;
     };
 
     struct NewPaneSubcommand : public NewTerminalSubcommand
@@ -105,6 +106,7 @@ class TerminalApp::AppCommandlineArgs final
 
     // _commandline will contain the command line with which we'll be spawning a new terminal
     std::vector<std::string> _commandline;
+    bool _appendCommandLineOption{ false };
 
     bool _splitVertical{ false };
     bool _splitHorizontal{ false };

src/cascadia/TerminalApp/Resources/en-US/Resources.resw

@@ -840,4 +840,7 @@
     <value>Run as Administrator</value>
     <comment>This text is displayed on context menu for profile entries in add new tab button.</comment>
   </data>
-</root>
+  <data name="CmdAppendCommandLineDesc" xml:space="preserve">
+    <value>If set, the command will be appended to the profile's default command instead of replacing it.</value>
+  </data>
+</root>

src/cascadia/TerminalSettingsModel/ActionArgs.h

@@ -309,6 +309,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         ACTION_ARG(Windows::Foundation::IReference<Windows::UI::Color>, TabColor, nullptr);
         ACTION_ARG(Windows::Foundation::IReference<int32_t>, ProfileIndex, nullptr);
         ACTION_ARG(winrt::hstring, Profile, L"");
+        ACTION_ARG(bool, AppendCommandLine, false);
         ACTION_ARG(Windows::Foundation::IReference<bool>, SuppressApplicationTitle, nullptr);
         ACTION_ARG(winrt::hstring, ColorScheme);
         ACTION_ARG(Windows::Foundation::IReference<bool>, Elevate, nullptr);
@@ -320,6 +321,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         static constexpr std::string_view TabColorKey{ "tabColor" };
         static constexpr std::string_view ProfileIndexKey{ "index" };
         static constexpr std::string_view ProfileKey{ "profile" };
+        static constexpr std::string_view AppendCommandLineKey{ "appendCommandLine" };
         static constexpr std::string_view SuppressApplicationTitleKey{ "suppressApplicationTitle" };
         static constexpr std::string_view ColorSchemeKey{ "colorScheme" };
         static constexpr std::string_view ElevateKey{ "elevate" };
@@ -340,6 +342,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                        otherAsUs->_TabColor == _TabColor &&
                        otherAsUs->_ProfileIndex == _ProfileIndex &&
                        otherAsUs->_Profile == _Profile &&
+                       otherAsUs->_AppendCommandLine == _AppendCommandLine &&
                        otherAsUs->_SuppressApplicationTitle == _SuppressApplicationTitle &&
                        otherAsUs->_ColorScheme == _ColorScheme &&
                        otherAsUs->_Elevate == _Elevate &&

src/cascadia/TerminalSettingsModel/ActionArgs.idl

@@ -132,6 +132,7 @@ namespace Microsoft.Terminal.Settings.Model
         String TabTitle;
         Windows.Foundation.IReference<Windows.UI.Color> TabColor;
         String Profile; // Either a GUID or a profile's name if the GUID isn't a match
+        Boolean AppendCommandLine;
 
         // We use IReference<> to treat some args as nullable where null means
         // "use the inherited value". See ProfileIndex,

src/cascadia/TerminalSettingsModel/TerminalSettings.cpp

@@ -129,7 +129,14 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
             // Override commandline, starting directory if they exist in newTerminalArgs
             if (!newTerminalArgs.Commandline().empty())
             {
-                defaultSettings.Commandline(newTerminalArgs.Commandline());
+                if (!newTerminalArgs.AppendCommandLine())
+                {
+                    defaultSettings.Commandline(newTerminalArgs.Commandline());
+                }
+                else
+                {
+                    defaultSettings.Commandline(defaultSettings.Commandline() + L" " + newTerminalArgs.Commandline());
+                }
             }
             if (!newTerminalArgs.StartingDirectory().empty())
             {