Run Task Freezes for some Variable References

Discussed in https://github.com/microsoft/vscode-cpptools/discussions/10686

^{Originally posted by shengchao-lin March 15, 2023}
When variable reference is used that relates to the current file, e.g., ${file}, ${fileBasename}, etc, the run task freezes. However, a simple echo does not. See the example below. Task "My C++ build" hangs but "echo" does not.

When freezing, the terminal tab shows:

If task "echo" is ran first, launched the terminal tab, and ran successfully, then task "My C++ build" can ran successfully too.

Additionally, when the "${workspaceFolder}/${fileBasename}" is replaced with something like "${workspaceFolder}/main.cpp", the task "My C++ build" runs successfully.

What could be the issue here?

"tasks": [
{
	"type": "cppbuild",
	"label": "build",
	"command": "g++",
	"args": [
		"-fdiagnostics-color=always",
		"-g",
		"${workspaceFolder}/${fileBasename}",
		"-o",
		"${workspaceFolder}/output",
		"-std=c++20"
	],
	"detail": "compiler: /usr/bin/g++",
	"group": {
		"kind": "build",
		"isDefault": true
	}
},
{
	"type": "shell",
	"label": "echo",
	"command": "echo ${workspaceFolder}/${fileBasename}",
}
]

Platform: MacOS Ventura 13.2.1
VSCODE:
Version: 1.76.2
Commit: ee2b180d582a7f601fa6ecfdad8d9fd269ab1884
Date: 2023-03-14T17:54:09.061Z
Electron: 19.1.11
Chromium: 102.0.5005.196
Node.js: 16.14.2
V8: 10.2.154.26-electron.0
OS: Darwin x64 22.3.0
Sandboxed: No

Extension used: C/C++

Start with the linked discussion and reproduce the task configuration using ${workspaceFolder}/${fileBasename} versus a literal filename. Compare the freezing C++ build task with the working echo task, and verify that the task completes reliably on the reported macOS and VS Code versions.