[Regression] Show counterexamples failing with "Counterexample request failed: TypeError: Cannot convert undefined or null to object"

[AlgorithmsAreCool]

Dafny Extension v3.3.1

Version: 1.92.2
Commit: fee1edb8d6d72a0ddff41e5f71a671c23ed924b9
Date: 2024-08-14T17:29:30.058Z
Electron: 30.1.2
ElectronBuildId: 9870757
Chromium: 124.0.6367.243
Node.js: 20.14.0
V8: 12.4.254.20-electron.0
OS: Windows_NT x64 10.0.19045

Thank you all for this incredible tool!

When attempting to show counterexamples in VSCode, it now fails with an error popup that says Counterexample request failed: TypeError: Cannot convert undefined or null to object

I've confirmed that reinstalling extension v3.3.0 fixes the issue.

The output window only displays the following.

Language server: {"command":"C:\\Program Files\\dotnet\\dotnet.EXE","args":["c:\\Users\\alfred\\scoop\\apps\\vscode\\1.92.2\\data\\extensions\\dafny-lang.ide-vscode-3.3.1\\out\\resources\\4.7.0\\github\\dafny\\Dafny.dll","server","--verify-on:Change","--verification-time-limit:0","--cache-verification=0","--cores:9","--notify-ghostness:true","--notify-line-verification-status:true"]}
Dafny is ready

Unsure how to collect additional info but happy to help however i can.

[AlgorithmsAreCool]

This seems to still be happening in v3.4.1 of the extension

[keyboardDrummer]

This was broken by dafny-lang/dafny#5013, which changes the counterexample API provided by dafny server. I'm not sure why that API was updated. There were internal changes in that PR made to enable the dafny verify --extract-counterexample option, that possibly made it difficult not to update the dafny server API as well, I'm not sure.

We should consider reverting the dafny server counterexample API to what it was, or otherwise think about how we could visually display the new API.