Debug launch configuration doesn't override Python interpreter

[pascalvenema]

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

• VS Code Version: 1.105.1 (Universal)
• OS Version: macOS 26.0.1

Issue:

I am using a multi-root workspace for my monorepo. I am using a monorepo.code-workspace file that roughly looks like the following:

{
  "folders": [
    {
      "name": "root",
      "path": "."
    },
    {
      "name": "service_A",
      "path": "service_A"
    },
    {
      "name": "service_B",
      "path": "service_B"
    },
    {
      "name": "company_python",
      "path": "company_python"
    },
  ],
  "launch": {
    "version": "0.2.0",
    "configurations": [
      {
        "name": "service_A",
        "consoleName": "service_A",
        "type": "debugpy",
        "request": "launch",
        "module": "uvicorn",
        "args": [
          "app.main:app",
          "--reload",
          "--reload-dir",
          "${workspaceFolder:service_A}",
          "--reload-dir",
          "${workspaceFolder:root}/company_python",
        ],
        "justMyCode": true,
        "console": "integratedTerminal",
        "env": {
          "POETRY_ACTIVE": "1",
          "PYTHONPATH": "${workspaceFolder:service_A}:${workspaceFolder:root}/company_python"
        },
        "cwd": "${workspaceFolder:service_A}",
        "python": "${workspaceFolder:service_A}/.venv/bin/python",
        "windows": {
          "python": "${workspaceFolder:service_A}\\.venv\\Scripts\\python.exe"
        }
      },
      {
        "name": "service_B",
        "consoleName": "service_B",
        "type": "debugpy",
        "request": "launch",
        "module": "uvicorn",
        "args": [
          "app.main:app",
          "--port",
          "8001",
          "--reload",
          "--reload-dir",
          "${workspaceFolder:service_B}",
          "--reload-dir",
          "${workspaceFolder:root}/company_python",
        ],
        "justMyCode": true,
        "console": "integratedTerminal",
        "env": {
          "POETRY_ACTIVE": "1",
          "PYTHONPATH": "${workspaceFolder:service_B}:${workspaceFolder:root}/company_python"
        },
        "cwd": "${workspaceFolder:service_B}",
        "python": "${workspaceFolder:service_B}/.venv/bin/python",
        "windows": {
          "python": "${workspaceFolder:service_B}\\.venv\\Scripts\\python.exe"
        }
      }
    ]
  },
  "settings": {
    "files.exclude": {
      "service_A": true,
      "service_B": true
      // "company_python": true,
    },
    "search.exclude": {
      "service_A": true,
      "service_B": true
      // "company_python": true,
    },
    "python.analysis.extraPaths": [
      "${workspaceFolder:root}/company_python"
    ],
    "python.autoComplete.extraPaths": [
      "${workspaceFolder:root}/company_python"
    ]
  }
}

The lines that are important are:

"python": "${workspaceFolder:service_A}/.venv/bin/python",

When I hover over this, it hints at the following:

However, when I launch the debug configuration for either service_A or service_B, it does not use the path I configured in monorepo.code-workspace. Instead, VS Code look at which file is currently open, and checks which interpreter is configured 'locally'.

Even when I clear all settings regarding the interpreters, it still does not use the interpreter that I have configured in the debug launch config.

Steps to Reproduce:

1. Use the monorepo.code-workspace that I provided above.
2. Create a .venv for both service_A and service_B.
3. To make sure this bug occurs, select the correct interpreters for both folders using the command Python: Select Interpreter as shown in the screenshot above.
4. Have a .py file open that lives in the folder of service_B.
5. Start the debug configuration for service_A.
6. Check the integrated terminal to see that the debugger looks at the .venv of service_B.

[eleanorjboyd]

Thank you for this detailed report! I will investigate but in the meantime can you provide the versioning for your python extension, debugger extension and then if you have the python environments extension enabled? You can enable / disable that extension with python.useEnvironmentsExtension in your settings. Toggling may also get you another result so I am curious what toggling it on does as this should change the interpreter selection process