Terminal: revive makes the terminal very slow to start

[bpasero]

Testing #133516

When having the setting enabled to revive terminals, I feel like the terminal needs seconds to open after a restart, vs. otherwise when not enabled.

[bpasero]

[Tyriar]

I wonder how much of this is due to the shared process launching slowly, as opposed to reconnection which doesn't need to wait for that.

[Tyriar]

Revive does indeed take a lot longer than a regular reconnect.

Revive:

Reconnect:

[Tyriar]

Found the main cause, before attach to a pty happens there's a check for whether it's orphaned:

vscode/src/vs/platform/terminal/node/ptyService.ts

Line 363 in 4a7cd94

const [cwd, isOrphan] = await Promise.all([persistentProcess.getCwd(), persistentProcess.isOrphaned()]);

For freshly revived processes, there is no window to respond to the parent request so it waits for the barrier's 4000ms before resolving:

vscode/src/vs/platform/terminal/node/ptyService.ts

Line 662 in 4a7cd94

this._orphanQuestionBarrier = new AutoOpenBarrier(4000);

So, the fix for this this should trim off about 4 seconds of revive time.