Expose a terminal API option to pause when the shell is exited

[Tyriar]

This is a requirement for the tasks framework to be moved to using the integrated terminal. The idea is to allow extensions to optionally specify they don't want the terminal to go away immediately after the shell process is exited but instead wait for input.

This would allow the tasks framework (and other extensions) to run a command that exits the shell immediately afterwards, and then wait for a keystroke or for the terminal to be killed manually, for example:

gulp build
...
...

Press and key to close the terminal...

Proposed API:

export function createTerminal(name?: string, shellPath?: string, shellArgs?: string[], waitOnExit?: boolean): Terminal;

/cc @jrieken @dbaeumer

[jrieken]

We might have reached a point where it makes sense to talk about a second overload with an options bag. Like

export function createTerminal(name?: string, shellPath?: string, shellArgs?: string[]): Terminal;

export function createTerminal(options: {name?: string; shellPath?: string; shellArgs?: string[]; waitOnExit?: boolean }): Terminal;

[Tyriar]

Upstream issue to implement disableStdin (prereq) xtermjs/xterm.js#452 (PR xtermjs/xterm.js#453)

[Tyriar]

Upstream PR is merged in

[Tyriar]

PR that exposes the new waitOnExit option to API: #18336
Example usage: microsoft/vscode-extension-samples@9b46d6b

[Tyriar]

@dbaeumer FYI currently if a waitOnExit shell exits with a non-0 code I print the message that would normally go in the message box inside the terminal:

[Tyriar]

FYI @dbaeumer @jrieken I've pulled the waitOnExit option out of the API for now as it might become an enum (see #18661). I've left TerminalOptions in as it will come later anyhow.

[Tyriar]

No longer needed (yet), closing off.

[jrieken]

I hope we still have use for TerminalOptions... We need more options ;-)

[Tyriar]

@jrieken the hope is still to move tasks to an extension, it's not the priority now though. A lot of the stuff that tasks need would be great for extensions to be able to hook into eventually as well, now we're just not rushed in pushing the APIs out. Some things that I can see us adding soon:

• A more focused waitOnExit after we've received more feedback from tasks
• Ability to set the terminal environment