Add launch profile option to use integrated terminal

[drewnoakes]

Today, when launching a console app, a new terminal window is opened.

VS has an integrated terminal that appears within a tool window.

The debugging infrastructure supports a launch option to do this. We just need to plumb it through from the UI, to launchSettings.json, to the launch invocation.

We might also want to add an option (Tools|Options) that controls the default value for when the property is not present in the launchSettings.json.

For an example of integrating this feature, see https://devdiv.visualstudio.com/DevDiv/_git/WebTools/pullrequest/425844?_a=files&path=/src/ProjectSystem/Web/WebServer/SelfHostWebServer.cs (MS internal).

[drewnoakes]

Sharing some findings.

Enabling this feature is straightforward:

diff --git a/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/Debug/ProjectLaunchTargetsProvider.cs b/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/Debug/ProjectLaunchTargetsProvider.cs
index 1c095a8fb..7cada1fa0 100644
--- a/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/Debug/ProjectLaunchTargetsProvider.cs
+++ b/src/Microsoft.VisualStudio.ProjectSystem.Managed.VS/ProjectSystem/VS/Debug/ProjectLaunchTargetsProvider.cs
@@ -360,7 +360,8 @@ private async Task<bool> IsIntegratedConsoleEnabledAsync()
             {
                 if (await IsIntegratedConsoleEnabledAsync())
                 {
-                    settings.LaunchOptions |= DebugLaunchOptions.IntegratedConsole;
+                    const int DBGLAUNCH_UseIntegratedTerminalService = 0x20000000;
+                    settings.LaunchOptions |= DebugLaunchOptions.IntegratedConsole | (DebugLaunchOptions)DBGLAUNCH_UseIntegratedTerminalService;
                 }

                 useCmdShell = UseCmdShellForConsoleLaunch(resolvedProfile, settings.LaunchOptions);

The result is this:

Despite it being easy to turn this feature on, there are a few open questions:

• How do we allow users to configure this? Currently the ⚙️ icon in the terminal window launches the Web Tools settings, where an option for this lives. The option should be centralised in the Debugging area. The screenshot shows a console app.
• The terminal window pane is visible during debugging (just like Call Stack, Locals, etc) and closes when debugging stops. Having the program's output disappear when the process exits doesn't seem great. Consider if the app crashes — there's no way to see logged errors.
• If you Ctrl+F5, the terminal window is visible and remains in the UI (avoiding the previous issue). However if you then F5, a different instance of the terminal is displayed during debugging, then the non-debug terminal is displayed again when the debugging session ends, which is confusing.

Overall, I like the idea of adding this but we will need to work through the above issues with other teams before we can ship this.

[drewnoakes]

CPS PR to add DebugLaunchOptions member: https://dev.azure.com/devdiv/DevDiv/_git/CPS/pullrequest/524465

[drewnoakes]

Feature request for this on developer community: https://developercommunity.visualstudio.com/t/display-c-console-app-output-in-internal-terminal/1224895