Hygiene: get rid of all instances of hstring ctor'd with L"" (#17655)

One of these things can be optimized. It's not the one you thought.

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -1448,8 +1448,8 @@ namespace winrt::TerminalApp::implementation
         const auto source = realArgs.Source();
         std::vector<Command> commandsCollection;
         Control::CommandHistoryContext context{ nullptr };
-        winrt::hstring currentCommandline = L"";
-        winrt::hstring currentWorkingDirectory = L"";
+        winrt::hstring currentCommandline;
+        winrt::hstring currentWorkingDirectory;
 
         // If the user wanted to use the current commandline to filter results,
         //    OR they wanted command history (or some other source that
@@ -1479,7 +1479,7 @@ namespace winrt::TerminalApp::implementation
             context.QuickFixes() != nullptr)
         {
             // \ue74c --> OEM icon
-            const auto recentCommands = Command::HistoryToCommands(context.QuickFixes(), hstring{ L"" }, false, hstring{ L"\ue74c" });
+            const auto recentCommands = Command::HistoryToCommands(context.QuickFixes(), hstring{}, false, hstring{ L"\ue74c" });
             for (const auto& t : recentCommands)
             {
                 commandsCollection.push_back(t);

src/cascadia/TerminalApp/TerminalPage.h

@@ -153,8 +153,8 @@ namespace winrt::TerminalApp::implementation
 
         winrt::fire_and_forget ProcessStartupActions(Windows::Foundation::Collections::IVector<Microsoft::Terminal::Settings::Model::ActionAndArgs> actions,
                                                      const bool initial,
-                                                     const winrt::hstring cwd = L"",
-                                                     const winrt::hstring env = L"");
+                                                     const winrt::hstring cwd = winrt::hstring{},
+                                                     const winrt::hstring env = winrt::hstring{});
 
         TerminalApp::WindowProperties WindowProperties() const noexcept { return _WindowProperties; };
 

src/cascadia/TerminalControl/ControlCore.cpp

@@ -2289,7 +2289,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
                 const auto trimmed = s.substr(0, strEnd + 1);
                 return winrt::hstring{ trimmed };
             }
-            return winrt::hstring{ L"" };
+            return {};
         };
 
         const auto currentCommand = _terminal->CurrentCommand();

src/cascadia/TerminalControl/TermControlAutomationPeer.cpp

@@ -319,7 +319,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             }
         }
 
-        return L"";
+        return {};
     }
 
     hstring TermControlAutomationPeer::GetHelpTextCore() const
@@ -328,7 +328,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         {
             return control->Title();
         }
-        return L"";
+        return {};
     }
 
     AutomationLiveSetting TermControlAutomationPeer::GetLiveSettingCore() const

src/cascadia/TerminalSettingsEditor/Appearances.cpp

@@ -884,7 +884,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 
     bool AppearanceViewModel::BackgroundImageSettingsVisible()
     {
-        return BackgroundImagePath() != L"";
+        return !BackgroundImagePath().empty();
     }
 
     void AppearanceViewModel::ClearColorScheme()

src/cascadia/TerminalSettingsModel/ActionAndArgs.cpp

@@ -344,7 +344,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
     winrt::hstring ActionAndArgs::GenerateName() const
     {
         // Sentinel used to indicate this command must ALWAYS be generated by GenerateName
-        static const winrt::hstring MustGenerate{ L"" };
+        static const winrt::hstring MustGenerate;
         // Use a magic static to initialize this map, because we won't be able
         // to load the resources at _init_, only at runtime.
         static const auto GeneratedActionNames = []() {
@@ -453,7 +453,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         }
 
         const auto found = GeneratedActionNames.find(_Action);
-        return found != GeneratedActionNames.end() ? found->second : L"";
+        return found != GeneratedActionNames.end() ? found->second : winrt::hstring{};
     }
 
     // Function Description:
@@ -483,7 +483,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
             }
             return winrt::hstring{ result };
         }
-        return L"";
+        return {};
     }
 
     winrt::hstring ActionAndArgs::Serialize(const winrt::Windows::Foundation::Collections::IVector<Model::ActionAndArgs>& args)

src/cascadia/TerminalSettingsModel/ActionArgs.cpp

@@ -116,7 +116,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         auto s = ss.str();
         if (s.empty())
         {
-            return L"";
+            return {};
         }
 
         // Chop off the last ", "
@@ -187,7 +187,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         auto s = ss.str();
         if (s.empty())
         {
-            return L"";
+            return {};
         }
 
         // Chop off the last " "
@@ -536,7 +536,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                             SchemeName().c_str())
             };
         }
-        return L"";
+        return {};
     }
 
     winrt::hstring SetTabColorArgs::GenerateName() const
@@ -579,7 +579,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                             Commandline().c_str())
             };
         }
-        return L"";
+        return {};
     }
 
     winrt::hstring CloseOtherTabsArgs::GenerateName() const
@@ -765,7 +765,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         case FindMatchDirection::Previous:
             return winrt::hstring{ RS_(L"FindPrevCommandKey") };
         }
-        return L"";
+        return {};
     }
 
     winrt::hstring NewWindowArgs::GenerateName() const
@@ -841,7 +841,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
 
         // We couldn't parse a URL out of this. Return no string at all, so that
         // we don't even put this into the command palette.
-        return L"";
+        return {};
     }
 
     winrt::hstring GlobalSummonArgs::GenerateName() const
@@ -909,12 +909,12 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         }
 
         // Return the empty string - the Clear() should be one of these values
-        return winrt::hstring{ L"" };
+        return {};
     }
 
     winrt::hstring MultipleActionsArgs::GenerateName() const
     {
-        return L"";
+        return {};
     }
 
     winrt::hstring AdjustOpacityArgs::GenerateName() const
@@ -968,7 +968,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
 
             return winrt::hstring{ ss.str() };
         }
-        return L"";
+        return {};
     }
 
     static winrt::hstring _FormatColorString(const Control::SelectionColor& selectionColor)
@@ -1095,7 +1095,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         case SelectOutputDirection::Previous:
             return RS_(L"SelectOutputPreviousCommandKey");
         }
-        return L"";
+        return {};
     }
     winrt::hstring SelectCommandArgs::GenerateName() const
     {
@@ -1106,6 +1106,6 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         case SelectOutputDirection::Previous:
             return RS_(L"SelectCommandPreviousCommandKey");
         }
-        return L"";
+        return {};
     }
 }

src/cascadia/TerminalSettingsModel/AppearanceConfig.cpp

@@ -148,7 +148,7 @@ winrt::hstring AppearanceConfig::ExpandedBackgroundImagePath()
         }
         else
         {
-            return winrt::hstring{ L"" };
+            return {};
         }
     }
     else

src/cascadia/UIHelpers/Converters.cpp

@@ -52,7 +52,7 @@ namespace winrt::Microsoft::Terminal::UI::implementation
 
     winrt::hstring Converters::StringOrEmptyIfPlaceholder(const winrt::hstring& placeholder, const winrt::hstring& value)
     {
-        return placeholder == value ? L"" : value;
+        return placeholder == value ? winrt::hstring{} : value;
     }
 
     // Misc