Debug sessions become unresponsive after a failed 'restart' request

[HampusAdolfsson]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.97.0-insider, commit 70866d5
• OS Version: Windows 11 10.0.22631 Build 22631

When a 'restart' request request fails, because the debug adapter returned success: false on the response, the entire debug session becomes unresponsive. Any attempt to interact with the session (even attempting to terminate it), produces the following message in the Extension Host logs, and no DAP request is ever sent to the debug adapter:

2025-01-07 17:13:53.909 [error] Error: Invalid debug adapter
    at IVt.p (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:705:100)
    at IVt.$acceptDAMessage (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:704:32926)
    at Lft.S (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:3165:41681)
    at Lft.Q (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:3165:41459)
    at Lft.M (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:3165:40547)
    at Lft.L (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:3165:39651)
    at Ree.value (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:3165:38445)
    at x.B (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:30:748)
    at x.fire (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:30:967)
    at uW.fire (vscode-file://vscode-app/c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code%20Insiders/resources/app/out/vs/workbench/workbench.desktop.main.js:723:10348)

This isn't specific to any extension or debug adapter; any adapter whose 'restart' request may fail seems to trigger the behaviour.

20250107-1619-15.1555441.mp4

Steps to Reproduce:

You can reproduce the issue with my fork of vscode-mock-debug or by applying this commit to the main vscode-mock-debug.

Then, follow the README instructions to start a debug session for a .md file, press restart, then attempt to do anything else with the session.