Feature request: Add reverse continue for TimeTravel Debugging feature for Node

[aruneshchandra]

This request builds on the following work that was done earlier to support TTD for Node in VSCode

• UI support for TimeTravel Debugging for Node
• Adding step back capability to VSCode node-debug adapter for TTD
• UI support for TimeTravel Debugging

According to some internal usability testing, we discovered a need to have a reverse continue button on the debug bar in order to enhance the usability of the time travel debugging for more complex scenarios.

/cc: @weinand, @isidorn, @roblourens, @mrkmarron

[weinand]

@aruneshchandra please explain the semantics of "reverse continue"

[aruneshchandra]

"Reverse continue" is suppose to work exactly like the "Debug Continue" with the difference being that it goes backwards and is only available while debugging a TTD trace. So, when the debugger is broken into while debugging a TTD trace, hitting reverse continue should execute backwards until the first (previous) break point is hit. To enable this VSCode can pass a stepback:continue command to the debug adapter and the TTD enabled runtime should handle the rest.

@mrkmarron - do you have anything else to add ?

[weinand]

@roblourens are you supporting back-in-time debugging in node-debug2 too?

[roblourens]

I don't think Node-chakra supports --inspect yet, although I think they're working on it.

[aruneshchandra]

@roblourens is right, --inspect is not supported in Node-ChakraCore yet , but we do plan to support it.
/cc: @digitalinfinity @agarwal-sandeep

[aruneshchandra]

any update on this ?

[weinand]

This is planned for the November release.

[aruneshchandra]

cool - when is the Nov release ? do we have a date ?

[isidorn]

@aruneshchandra the plan with the dates will be posted soon on GitHub - to get notified on each iteration plan you can follow Erich on twitter https://twitter.com/erichgamma?lang=en

[aruneshchandra]

Do we know when this might show up in Nightlies ? We will be showing a demo at NodeInteractive at the end of this month and wanted to see this in action before that.

[weinand]

We can make this happen.

[weinand]

@aruneshchandra what is the exact name for the stepaction attribute of the continue that is passed to chakra? For stepping back it was 'back'. The stepback:continue that you've mentioned above does not look proper.

[agarwal-sandeep]

Since the command is continue stepaction:"reverse" may be appropriate. @aruneshchandra @mrkmarron?

[weinand]

@isidorn I've added a reverseContinueRequest to the protocol. Please add an action button to the debug action floating palette if the supportsStepBack capability is true.

[weinand]

node-debug uses a value reverse for the stepaction attribute of the continue request.

[weinand]

@aruneshchandra 'reverse continue' has arrived in the Insiders build. If you install the "Mock Debug" extension, you can try the feature:

[aruneshchandra]

Thanx @weinand and @isidorn - this is great!