placeholder decoration is missing for cursor line on windows

[meganrogge]

1. create a terminal
2. press enter repeatedly
3. 🐛 the placeholder is always missing from the cursor line

[Tyriar]

I wasn't sure where I mentioned this but I've been thinking of an idea to more aggressively check the contents of the line on Windows whenever a conpty reprint occurs to validate the command is in the right spot, similar to what is done on resize only right now. Not sure about perf implications

[Tyriar]

This happens because conpty is printing the start sequences on the previous line:

[2022-06-23 08:00:17.341] [ptyhost] [debug] CommandDetectionCapability#handleCommandExecuted 34 undefined
[2022-06-23 08:00:17.341] [ptyhost] [debug] CommandDetectionCapability#setCommandLine 
[2022-06-23 08:00:17.341] [ptyhost] [debug] CommandDetectionCapability#handleCommandFinished 34 8  {"promptStartMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":1,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"commandStartX":0,"commandStartMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":2,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"commandStartLineContent":"PS C:\\Github\\lunapaint\\tga-codec>","commandExecutedX":34,"command":"","commandExecutedMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":2,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"commandFinishedMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":3,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}}}
[2022-06-23 08:00:17.341] [ptyhost] [debug] CommandDetectionCapability#onCommandFinished {"command":"","marker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":2,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"endMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":3,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"executedMarker":{"_disposables":[{},{},{},{}],"_isDisposed":false,"line":8,"_id":2,"isDisposed":false,"_onDispose":{"_listeners":[null],"_disposed":false}},"timestamp":1655996417341,"cwd":"C:\\Github\\lunapaint\\tga-codec","commandStartLineContent":"PS C:\\Github\\lunapaint\\tga-codec>","hasOutput":false}
[2022-06-23 08:00:17.342] [ptyhost] [debug] CommandDetectionCapability#handlePromptStart 34 8
[2022-06-23 08:00:17.356] [ptyhost] [debug] CommandDetectionCapability#_handleCommandStartWindows 34 8

[Tyriar]

This is one of those issues that isn't really possible to fix without messing with other heuristics, unless conpty positions the sequence correctly. The latter should happen soonish in microsoft/terminal#8698 and hopefully we'll be able to bundle a recent version of conpty instead of depending on the Windows release after that.