Display a warning if SUI is unable to write to the settings file (#19027)

Adds logic to display a warning popup if the settings.json is marked as
read-only and we try to write to the settings.json file. Previously,
this scenario would crash, which definitely isn't right. However, a
simple fix of "not-crashing" wouldn't feel right either.

This leverages the existing infrastructure to display a warning dialog
when we failed to write to the settings file. The main annoyance here is
that that popup dialog is located in `TerminalWindow` and is normally
triggered from a failed `SettingsLoadEventArgs`. To get around this,
`CascadiaSettings::WriteSettingsToDisk()` now returns a boolean to
signal if the write was successful; whereas if it fails, a warning is
added to the settings object. If we fail to write to disk, the function
will return false and we'll raise an event with the settings' warnings
to `TerminalPage` which passes it along to `TerminalWindow`.

Additionally, this uses `IVectorView<SettingsLoadWarnings>` as opposed
to `IVector<SettingsLoadWarnings>` throughout the relevant code. It's
more correct as the list of warnings shouldn't be mutable and the
warnings from the `CascadiaSettings` object are retrieved in that
format.

## Validation Steps Performed
- ✅ Using SUI, save settings when the settings.json is set to read-only

Closes #18913

src/cascadia/TerminalApp/AppLogic.cpp

@@ -392,7 +392,7 @@ namespace winrt::TerminalApp::implementation
                 auto ev = winrt::make_self<SettingsLoadEventArgs>(true,
                                                                   static_cast<uint64_t>(_settingsLoadedResult),
                                                                   _settingsLoadExceptionText,
-                                                                  warnings,
+                                                                  warnings.GetView(),
                                                                   _settings);
                 SettingsChanged.raise(*this, *ev);
                 return;
@@ -424,7 +424,7 @@ namespace winrt::TerminalApp::implementation
         auto ev = winrt::make_self<SettingsLoadEventArgs>(!initialLoad,
                                                           _settingsLoadedResult,
                                                           _settingsLoadExceptionText,
-                                                          warnings,
+                                                          warnings.GetView(),
                                                           _settings);
         SettingsChanged.raise(*this, *ev);
     }
@@ -491,7 +491,7 @@ namespace winrt::TerminalApp::implementation
         auto ev = winrt::make_self<SettingsLoadEventArgs>(false,
                                                           _settingsLoadedResult,
                                                           _settingsLoadExceptionText,
-                                                          warnings,
+                                                          warnings.GetView(),
                                                           _settings);
 
         auto window = winrt::make_self<implementation::TerminalWindow>(*ev, _contentManager);

src/cascadia/TerminalApp/SettingsLoadEventArgs.h

@@ -12,14 +12,14 @@ namespace winrt::TerminalApp::implementation
         WINRT_PROPERTY(bool, Reload, false);
         WINRT_PROPERTY(uint64_t, Result, S_OK);
         WINRT_PROPERTY(winrt::hstring, ExceptionText, L"");
-        WINRT_PROPERTY(winrt::Windows::Foundation::Collections::IVector<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>, Warnings, nullptr);
+        WINRT_PROPERTY(winrt::Windows::Foundation::Collections::IVectorView<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>, Warnings, nullptr);
         WINRT_PROPERTY(Microsoft::Terminal::Settings::Model::CascadiaSettings, NewSettings, nullptr);
 
     public:
         SettingsLoadEventArgs(bool reload,
                               uint64_t result,
                               winrt::hstring exceptionText,
-                              winrt::Windows::Foundation::Collections::IVector<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings> warnings,
+                              winrt::Windows::Foundation::Collections::IVectorView<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings> warnings,
                               Microsoft::Terminal::Settings::Model::CascadiaSettings newSettings) :
             _Reload{ reload },
             _Result{ result },

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -4165,6 +4165,13 @@ namespace winrt::TerminalApp::implementation
             }
         });
 
+        sui.ShowLoadWarningsDialog([weakThis{ get_weak() }](auto&& /*s*/, const Windows::Foundation::Collections::IVectorView<winrt::Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>& warnings) {
+            if (auto page{ weakThis.get() })
+            {
+                page->ShowLoadWarningsDialog.raise(*page, warnings);
+            }
+        });
+
         return *settingsContent;
     }
 

src/cascadia/TerminalApp/TerminalPage.h

@@ -187,6 +187,7 @@ namespace winrt::TerminalApp::implementation
         til::typed_event<IInspectable, IInspectable> OpenSystemMenu;
         til::typed_event<IInspectable, IInspectable> QuitRequested;
         til::typed_event<IInspectable, winrt::Microsoft::Terminal::Control::ShowWindowArgs> ShowWindowChanged;
+        til::typed_event<Windows::Foundation::IInspectable, Windows::Foundation::Collections::IVectorView<winrt::Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>> ShowLoadWarningsDialog;
 
         til::typed_event<Windows::Foundation::IInspectable, winrt::TerminalApp::RequestMoveContentArgs> RequestMoveContent;
         til::typed_event<Windows::Foundation::IInspectable, winrt::TerminalApp::RequestReceiveContentArgs> RequestReceiveContent;

src/cascadia/TerminalApp/TerminalPage.idl

@@ -97,6 +97,7 @@ namespace TerminalApp
 
         event Windows.Foundation.TypedEventHandler<Object, Object> OpenSystemMenu;
         event Windows.Foundation.TypedEventHandler<Object, Microsoft.Terminal.Control.ShowWindowArgs> ShowWindowChanged;
+        event Windows.Foundation.TypedEventHandler<Object, Windows.Foundation.Collections.IVectorView<Microsoft.Terminal.Settings.Model.SettingsLoadWarnings> > ShowLoadWarningsDialog;
 
         event Windows.Foundation.TypedEventHandler<Object, RequestMoveContentArgs> RequestMoveContent;
         event Windows.Foundation.TypedEventHandler<Object, RequestReceiveContentArgs> RequestReceiveContent;

src/cascadia/TerminalApp/TerminalWindow.cpp

@@ -220,6 +220,7 @@ namespace winrt::TerminalApp::implementation
         _root->Initialized({ get_weak(), &TerminalWindow::_pageInitialized });
         _root->WindowSizeChanged({ get_weak(), &TerminalWindow::_WindowSizeChanged });
         _root->RenameWindowRequested({ get_weak(), &TerminalWindow::_RenameWindowRequested });
+        _root->ShowLoadWarningsDialog({ get_weak(), &TerminalWindow::_ShowLoadWarningsDialog });
         _root->Create();
 
         AppLogic::Current()->SettingsChanged({ get_weak(), &TerminalWindow::UpdateSettingsHandler });
@@ -478,7 +479,7 @@ namespace winrt::TerminalApp::implementation
     //   validating the settings.
     // - Only one dialog can be visible at a time. If another dialog is visible
     //   when this is called, nothing happens. See ShowDialog for details
-    void TerminalWindow::_ShowLoadWarningsDialog(const Windows::Foundation::Collections::IVector<SettingsLoadWarnings>& warnings)
+    void TerminalWindow::_ShowLoadWarningsDialog(const IInspectable&, const Windows::Foundation::Collections::IVectorView<SettingsLoadWarnings>& warnings)
     {
         auto title = RS_(L"SettingsValidateErrorTitle");
         auto buttonText = RS_(L"Ok");
@@ -539,7 +540,7 @@ namespace winrt::TerminalApp::implementation
         }
         else if (settingsLoadedResult == S_FALSE)
         {
-            _ShowLoadWarningsDialog(_initialLoadResult.Warnings());
+            _ShowLoadWarningsDialog(nullptr, _initialLoadResult.Warnings());
         }
     }
 
@@ -825,7 +826,7 @@ namespace winrt::TerminalApp::implementation
         }
         else if (args.Result() == S_FALSE)
         {
-            _ShowLoadWarningsDialog(args.Warnings());
+            _ShowLoadWarningsDialog(nullptr, args.Warnings());
         }
         else if (args.Result() == S_OK)
         {

src/cascadia/TerminalApp/TerminalWindow.h

@@ -189,7 +189,7 @@ namespace winrt::TerminalApp::implementation
                                    const winrt::hstring& contentKey,
                                    HRESULT settingsLoadedResult,
                                    const winrt::hstring& exceptionText);
-        void _ShowLoadWarningsDialog(const Windows::Foundation::Collections::IVector<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>& warnings);
+        void _ShowLoadWarningsDialog(const IInspectable& sender, const Windows::Foundation::Collections::IVectorView<Microsoft::Terminal::Settings::Model::SettingsLoadWarnings>& warnings);
 
         bool _IsKeyboardServiceEnabled();
 

src/cascadia/TerminalApp/TerminalWindow.idl

@@ -30,7 +30,7 @@ namespace TerminalApp
     {
         Boolean Reload { get; };
         UInt64 Result { get; };
-        IVector<Microsoft.Terminal.Settings.Model.SettingsLoadWarnings> Warnings { get; };
+        IVectorView<Microsoft.Terminal.Settings.Model.SettingsLoadWarnings> Warnings { get; };
         String ExceptionText { get; };
 
         Microsoft.Terminal.Settings.Model.CascadiaSettings NewSettings { get; };

src/cascadia/TerminalSettingsEditor/MainPage.cpp

@@ -680,7 +680,10 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
     void MainPage::SaveButton_Click(const IInspectable& /*sender*/, const RoutedEventArgs& /*args*/)
     {
         _settingsClone.LogSettingChanges(false);
-        _settingsClone.WriteSettingsToDisk();
+        if (!_settingsClone.WriteSettingsToDisk())
+        {
+            ShowLoadWarningsDialog.raise(*this, _settingsClone.Warnings());
+        }
     }
 
     void MainPage::ResetButton_Click(const IInspectable& /*sender*/, const RoutedEventArgs& /*args*/)

src/cascadia/TerminalSettingsEditor/MainPage.h

@@ -46,6 +46,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         Editor::ExtensionsViewModel ExtensionsVM() const noexcept { return _extensionsVM; }
 
         til::typed_event<Windows::Foundation::IInspectable, Model::SettingsTarget> OpenJson;
+        til::typed_event<Windows::Foundation::IInspectable, Windows::Foundation::Collections::IVectorView<Model::SettingsLoadWarnings>> ShowLoadWarningsDialog;
 
     private:
         Windows::Foundation::Collections::IObservableVector<IInspectable> _breadcrumbs;

src/cascadia/TerminalSettingsEditor/MainPage.idl

@@ -39,6 +39,7 @@ namespace Microsoft.Terminal.Settings.Editor
 
         void UpdateSettings(Microsoft.Terminal.Settings.Model.CascadiaSettings settings);
         event Windows.Foundation.TypedEventHandler<Object, Microsoft.Terminal.Settings.Model.SettingsTarget> OpenJson;
+        event Windows.Foundation.TypedEventHandler<Object, Windows.Foundation.Collections.IVectorView<Microsoft.Terminal.Settings.Model.SettingsLoadWarnings> > ShowLoadWarningsDialog;
 
         // Due to the aforementioned bug, we can't use IInitializeWithWindow _here_ either.
         // Let's just smuggle the HWND in as a UInt64 :|

src/cascadia/TerminalSettingsModel/CascadiaSettings.h

@@ -167,7 +167,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         winrt::Windows::Foundation::Collections::IVectorView<Model::ExtensionPackage> Extensions();
         void ResetApplicationState() const;
         void ResetToDefaultSettings();
-        void WriteSettingsToDisk();
+        bool WriteSettingsToDisk();
         Json::Value ToJson() const;
         Model::Profile ProfileDefaults() const;
         Model::Profile CreateNewProfile();

src/cascadia/TerminalSettingsModel/CascadiaSettings.idl

@@ -31,7 +31,7 @@ namespace Microsoft.Terminal.Settings.Model
         CascadiaSettings Copy();
         void ResetApplicationState();
         void ResetToDefaultSettings();
-        void WriteSettingsToDisk();
+        Boolean WriteSettingsToDisk();
         void LogSettingChanges(Boolean isJsonLoad);
 
         String Hash { get; };

src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp

@@ -1226,15 +1226,7 @@ try
     // settings string back to the file.
     if (mustWriteToDisk)
     {
-        try
+        settings->WriteSettingsToDisk();
-        {
-            settings->WriteSettingsToDisk();
-        }
-        catch (...)
-        {
-            LOG_CAUGHT_EXCEPTION();
-            settings->_warnings.Append(SettingsLoadWarnings::FailedToWriteToSettings);
-        }
     }
     else
     {
@@ -1539,7 +1531,7 @@ void CascadiaSettings::ResetToDefaultSettings()
 // - <none>
 // Return Value:
 // - <none>
-void CascadiaSettings::WriteSettingsToDisk()
+bool CascadiaSettings::WriteSettingsToDisk()
 {
     // write current settings to current settings file
     Json::StreamWriterBuilder wbuilder;
@@ -1547,7 +1539,17 @@ void CascadiaSettings::WriteSettingsToDisk()
     wbuilder.settings_["indentation"] = "    ";
     wbuilder.settings_["precision"] = 6; // prevent values like 1.1000000000000001
 
-    _writeSettingsToDisk(Json::writeString(wbuilder, ToJson()));
+    try
+    {
+        _writeSettingsToDisk(Json::writeString(wbuilder, ToJson()));
+    }
+    catch (...)
+    {
+        LOG_CAUGHT_EXCEPTION();
+        _warnings.Append(SettingsLoadWarnings::FailedToWriteToSettings);
+        return false;
+    }
+    return true;
 }
 
 void CascadiaSettings::_writeSettingsToDisk(std::string_view contents)

src/inc/til/io.h

@@ -256,7 +256,11 @@ namespace til // Terminal Implementation Library. Also: "Today I Learned"
             // renaming one is (supposed to be) atomic.
             // Wait... "supposed to be"!? Well it's technically not always atomic,
             // but it's pretty darn close to it, so... better than nothing.
-            std::filesystem::rename(tmpPath, resolvedPath);
+            std::filesystem::rename(tmpPath, resolvedPath, ec);
+            if (ec)
+            {
+                THROW_WIN32_MSG(ec.value(), "failed to write to file");
+            }
         }
     } // io
 } // til