Maintain expand/collapse state of items in the variables panel when stepping through code in debug mode

[PranayAgarwal]

When using the debugger, everything in the variables panel gets collapsed on every step. This is especially annoying when trying to examine a nested structure.

I had initially thought this was a default VS Code behavior, but according to microsoft/vscode#32199 the state is determined by the debug server itself. Can dig bit deeper into this and see if this can be fixed in the extension debug adapter or by HHVM.

[ebluestein]

That's interesting that they said that - I am not sure what VS Code is keying off of in the UI. There is no expansion state maintained by the debug adapter, or communicated in the protocol.

Things stay expanded as expected in Nuclide, so this must be an interaction with VS Code.

One thought off the top of my head is the IDs of Scopes and Variables change with each ScopesResponse and VariablesResponse - maybe VS Code is tracking expansion state by object ID instead of path?

[PranayAgarwal]

Yeah the ID change is most likely causing it

[ebluestein]

Let me see what I can do here...

[ebluestein]

I pushed 83e2be29c4c771cf2ce5c158c2c43af1d518329d which will keep variableReference IDs for the same object stable within a request.

I'm not certain how VS Code is tracking expansion state, but if it's by variableReference like we thought above, I think this should take care of it for you