Unable to debug tests: Invalid message: Found duplicate in "env": PATH

Type: Bug

Plugin Versions

Python: v2024.2.1
Python Debugger: v2024.2.0

Behaviour

Expected vs. Actual

Expected: When selecting "debug test" from test runner or the editor, the debugger should start.

Actual: Debugger fails to start. Popup dialog with message "Invalid message: Found duplicate in "env": PATH." is displayed.

Steps to reproduce:

Open a new folder in VS Code
Add a single file with a dummy unit test like this:

import unittest


class SomeTest(unittest.TestCase):
    def test_anything(self):
        self.assertTrue(True)

Configure Python tests
Try to debug the test

Diagnostic data

Python version (& distribution if applicable, e.g. Anaconda): 3.8.10
Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Global
Value of the python.languageServer setting: Default

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

2024-03-12 17:28:25.416 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.421 [debug] starting server as TCP
2024-03-12 17:28:25.421 [debug] starting server as TCP
2024-03-12 17:28:25.423 [info] Using launch configuration in workspace folder.
2024-03-12 17:28:25.423 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.423 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.464 [debug] Activation Commands received undefined for shell cmd, resource c:\UserData\z003emnm\temp\duplicate_env_repro\test1 and interpreter C:\Python38\python.exe
2024-03-12 17:28:25.472 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.473 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.473 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.478 [debug] CreateEnv Trigger - turned off in settings
2024-03-12 17:28:25.616 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.634 [debug] Extension ms-python.debugpy accessed getActiveEnvironmentPath with args: undefined
2024-03-12 17:28:25.639 [debug] Extension ms-python.debugpy accessed resolveEnvironment with args: {"id":"C:\\PYTHON38\\PYTHON.EXE","path":"C:\\Python38\\python.exe"}
2024-03-12 17:28:25.647 [debug] Found cached env for C:\Python38\python.exe
2024-03-12 17:28:25.668 [debug] Extension ms-python.debugpy accessed resolveEnvironment with args: "C:\\Python38\\python.exe"
2024-03-12 17:29:10.882 [debug] Clearing context for python dependencies not installed: ms-python.python.Python
2024-03-12 17:29:10.883 [debug] Found cached env for C:\Python38\python.exe

Output for Python Debugger

``` 2024-03-12 17:26:32.337 [info] Name: Python Debugger 2024-03-12 17:26:32.337 [info] Module: debugpy 2024-03-12 17:27:29.664 [info] DAP Server launched with command: C:\Python38\python.exe c:\Users\z003emnm\.vscode\extensions\ms-python.debugpy-2024.2.0-win32-x64\bundled\libs\debugpy\adapter 2024-03-12 17:28:25.647 [info] DAP Server launched with command: C:\Python38\python.exe c:\Users\z003emnm\.vscode\extensions\ms-python.debugpy-2024.2.0-win32-x64\bundled\libs\debugpy\adapter ```

User Settings


languageServer: "Pylance"

testing
• unittestArgs: ["-v", "-s", ".", "-p", "test_*.py"]
• unittestEnabled: true

experiments
• enabled: false

Extension version: 2024.2.0
VS Code version: Code 1.87.0 (019f4d1419fbc8219a181fab7892ebccf7ee29a2, 2024-02-27T23:41:44.469Z)
OS version: Windows_NT x64 10.0.19045
Modes:

System Info

Item	Value
CPUs	11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz (16 x 2496)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled
Load (avg)	undefined
Memory (System)	31.67GB (19.24GB free)
Process Argv	. --crash-reporter-id ad5562b9-4802-4e9d-83ef-990f176f3ed1
Screen Reader	no
VM	0%

A/B Experiments

vsliv368cf:30146710
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscoreces:30445986
vscod805cf:30301675
binariesv615:30325510
vsaa593cf:30376535
py29gd2263:30899288
c4g48928:30535728
azure-dev_surveyone:30548225
vscrp:30673768
962ge761:30959799
pythongtdpath:30769146
welcomedialog:30910333
pythonidxpt:30866567
pythonnoceb:30805159
asynctok:30898717
pythontestfixt:30902429
pythonregdiag2:30936856
pyreplss1:30897532
pythonmypyd1:30879173
pythoncet0:30885854
pythontbext0:30879054
accentitlementsc:30887149
dsvsc016:30899300
dsvsc017:30899301
dsvsc018:30899302
pydisww1:30981707
cppperfcontrol:30979541
8082a590:30971561
fegfb526:30981948
bg6jg535:30979843
dsvsc020:30976470

I know there also exists microsoft/vscode-python#10722, but as the debugger is now a separate extension I was not sure if this should now be handled in this repo?

I tried to reproduce this issue on a second Windows machine (Windows 11), but there it worked fine.
The problem occurs on my work laptop with Windows 10.

What I also tried so far:

Cleaned all contents from user settings.json: no success
Disabled all extensions, only enabled Python and Python Debugger extension: no success

There is no .env file in the workspace:

C:.
│   test_something.py
│
├───.vscode
│       settings.json
│
└───__pycache__
        test_something.cpython-38.pyc

For reference, here is my full user settings.json:

User settings.json

{
    "workbench.startupEditor": "none",
    "workbench.editorAssociations": {
      "*.ipynb": "jupyter-notebook"
    },
    "notebook.cellToolbarLocation": {
      "default": "right",
      "jupyter-notebook": "left"
    },
    "terminal.integrated.defaultProfile.windows": "Command Prompt",
    "cmake.configureOnOpen": false,
    "csharp.suppressDotnetInstallWarning": true,
    "python.formatting.provider": "black",
    "[python]": {
      "editor.defaultFormatter": "ms-python.black-formatter",
      "editor.formatOnType": true
    },
    "files.exclude": {
      "**/__pycache__": true,
      "**/*.pyc": true
    },
    "testOnSave.testCommand": "",
    "python.defaultInterpreterPath": "C:\\Python38\\Scripts\\python.exe",
    "explorer.confirmDragAndDrop": false,
    "editor.formatOnSave": true,
    "workbench.iconTheme": "vscode-icons",
    "plantuml.server": "...",
    "plantuml.render": "PlantUMLServer",
    "remote.SSH.remotePlatform": {
      "dev-ec2": "linux",
      "ssm-dev-ec2": "linux"
    },
    "redhat.telemetry.enabled": false,
    "vsicons.dontShowNewVersionMessage": true,
    "java.configuration.runtimes": [
      {
        "name": "...",
        "path": "..."
      }
    ],
    "maven.settingsFile": "C:\\ProgramData\\chocolatey\\lib\\maven\\apache-maven-3.8.6\\conf\\settings.xml",
    "java.configuration.maven.userSettings": "C:\\ProgramData\\chocolatey\\lib\\maven\\apache-maven-3.8.7\\conf\\settings.xml",
    "testOnSave.languageId": "",
    "editor.stickyScroll.enabled": true,
    "git.autofetch": true,
    "markdown.validate.enabled": true,
    "git.confirmSync": false,
    "eslint.workingDirectories": ["frontend"],
    "workbench.colorTheme": "Default Dark+",
    "prettier.printWidth": 160,
    "[html]": {
      "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "sonarlint.rules": {
      "python:S107": {
        "level": "off"
      }
    },
    "java.configuration.maven.globalSettings": "C:\\ProgramData\\chocolatey\\lib\\maven\\apache-maven-3.8.7\\conf\\settings.xml",
    "java.configuration.updateBuildConfiguration": "automatic",
    "boot-java.rewrite.reconcile": true,
    "java.format.settings.url": "...",
    "[json]": {
      "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "maven.terminal.useJavaHome": true,
    "explorer.confirmDelete": false,
    "[typescript]": {
      "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "prettier.singleQuote": true,
    "pylint.importStrategy": "fromEnvironment",
    "editor.renderWhitespace": "trailing",
    "robot.variables": {},
    "editor.guides.bracketPairs": "active",
    "editor.detectIndentation": false,
    "window.zoomLevel": -1,
    "[markdown]": {
      "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "jupyter.askForKernelRestart": false,
    "[jsonc]": {
      "editor.defaultFormatter": "esbenp.prettier-vscode"
    },
    "robot.completions.keywords.prefixImportName": true,
    "continue.telemetryEnabled": false,
    "continue.enableTabAutocomplete": false,
    "mypy-type-checker.importStrategy": "fromEnvironment",
    "mypy-type-checker.args": ["--ignore-missing-imports", "--implicit-optional"],
    "accessibility.signals.terminalQuickFix": {
      "sound": "on"
    },
    "markdownlint.config": {
      "MD024": {
        "siblings_only": true
      }
    },
    "python.experiments.enabled": false
  }

In addition, the config setting for Python: Env File is set to: ${workspaceFolder}/.env (both in User and in Workspace settings).

If there is any additional information that I can provide to help find the root cause, please let me know.

With the following launch.json debugging works:

{
  // Use IntelliSense to learn about possible attributes.
  // Hover to view descriptions of existing attributes.
  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Python Debugger: Debug Test",
      "purpose": ["debug-test"],
      "type": "debugpy",
      "request": "launch",
      "program": "${file}",
      "console": "integratedTerminal"
    }
  ]
}

Changing console to internalConsole makes the issue reappear.
Shouldn't this have been fixed via microsoft/vscode-python#21033?

Hello! Sorry for the delay but are you still experiencing this issue?

Hi! Yes, the issue still exists. The workaround with the modified launch.json and the use of "console": "integratedTerminal" is still required.

I am using the current version 1.93.1:

Version: 1.93.1 (system setup)
Commit: 38c31bc77e0dd6ae88a4e9cc93428cc27a56ba40
Date: 2024-09-11T17:20:05.685Z
Electron: 30.4.0
ElectronBuildId: 10073054
Chromium: 124.0.6367.243
Node.js: 20.15.1
V8: 12.4.254.20-electron.0
OS: Windows_NT x64 10.0.19045

Just to add a datapoint: I have the same issue. I'm also on Win10, but I get the error regardless of launch.json having "console": "integratedTerminal" or "console": "internalConsole".

I found what caused the issue for me. There was an incorrect entry in the Path environment variable in windows. There was a folderpath which contained a /, which is forbidden under windows. (Going from the name, it was caused by GlazeWM, but I'm not pointing fingers.)

After removing the entry, I could debug tests again.

Hope that is helpful for some of you; maybe the error message could be improved to reflect this possible error source.

tmp modify handler.py:

if sys.platform == "win32":
    # Environment variables are case-insensitive on Win32, so we need to normalize
    # both dicts to make sure that env vars specified in the debug configuration
    # overwrite the global env vars correctly. If debug config has entries that
    # differ in case only, that's an error.
    env = {k.upper(): v for k, v in os.environ.items()}
    new_env_changes = {}
    for k, v in env_changes.items():
        k_upper = k.upper()
        if k_upper in new_env_changes:
            if new_env_changes[k_upper] == v:
                continue
            else:
                # modify by chenshichao  2025.03.19
                if True:
                    new_env_changes[k_upper] = f"{new_env_changes[k_upper]}:{v}"
                else:
                    raise request.isnt_valid(
                        'Found duplicate in "env": {0}.'.format(new_env_changes[k_upper])
                    )
        new_env_changes[k_upper] = v

rwijtvliet

rwijtvliet what path was the incorrect entry in the Path environment variable in windows.? Is this something the debugger extension added because if so I can investigate a fix there. Otherwise the error message update would be useful- you would just want it to communicate there is a potential problem in the PATH variable?

also 陈先生 (@ChenShiChao), is this a code suggestion or a fix for what rwijtvliet mentioned above?

Had the same problem. Reinstallation of VSCode solved the issue. 🤷

EDIT:
Perhaps some further information is appropriate.

I had the exact same problem as described by this Issue: When selecting "Debug Test" from the editor the debugger failed to start and a popup dialog with the message "Invalid message: Found duplicate in "env": PATH." was displayed.

What did I try?:

I checked my environment variables (see here). Nothing out of the ordinary. => Did not help in my case.
Used older versions of the "Python" and "Python Debugger" extension (in various combinations) => Did not help at all.
Added the property "purpose" with the value "["debug-test"]" to my launch configuration (saw that here) => I could execute the debugger exactly once, then the same message reappeared. I had to restart VSCode in order to use the debugger again (once). Very weird, I know.

What did help?:

I was frustrated because it seemed to work on my colleagues' computers, which had basically the same configuration. So I just installed VSCode again (did not even uninstall VSCode previously).
=> Works like a charm again (without any changes to my launch configuration).

Daniel (@DI84)

Daniel (@DI84) I experienced the same issue under the same conditions. I'm about to attempt re-installing my VSC.
Daniel (@DI84) no luck despite re-installing it.

EDIT:
I did have some duplicated path entries (both within the user and between the machine ones - courtesy of window's nmap or npcap tool I believe, I regret installingit) and some that ended with a slash.
After deleting them the issue didn't go away. I also attempted to reinstall VSC but no luck.

However the issue went away after rebooting. So do try that as well.

Karthik Nadig (@karthiknadig)

Hey Karthik Nadig (@karthiknadig), this issue might need further attention.

Andreas Finkler (@DudeNr33), you can help us out by closing this issue if the problem no longer exists, or adding more information.

I don't have access to the machine any more where this problem occurred, so I cannot really help any further here.
Printing out the actual duplicated entries in the error messages (or some log) would probably help others who have this problem to fix it.

Karthik Nadig (@karthiknadig)

Hey Karthik Nadig (@karthiknadig), this issue might need further attention.

Andreas Finkler (@DudeNr33), you can help us out by closing this issue if the problem no longer exists, or adding more information.

I had the same issue until I added "purpose" : "debug-test".
If I comment out "type": "debugpy", I see the same problem.

Don't know if this is relevant, but I am having this issue when using a .env file in my settings.json. If I remove the file, test debugging works (but the rest of my project doesn't).

Let me know if you need more info or if this is not the right place to comment about this.

Navigation Menu

Repository navigation

Unable to debug tests: Invalid message: Found duplicate in "env": PATH #261

Plugin Versions

Behaviour

Expected vs. Actual

Steps to reproduce:

Diagnostic data

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Unable to debug tests: Invalid message: Found duplicate in "env": PATH #261

Description

Plugin Versions

Behaviour

Expected vs. Actual

Steps to reproduce:

Diagnostic data

Activity

DudeNr33 commented on Mar 12, 2024

DudeNr33 commented on Mar 13, 2024

DudeNr33 commented on Mar 18, 2024

eleanorjboyd commented on Sep 18, 2024

DudeNr33 commented on Sep 23, 2024

rwijtvliet commented on Oct 7, 2024

rwijtvliet commented on Oct 21, 2024

ChenShiChao commented on Mar 19, 2025

eleanorjboyd commented on Mar 31, 2025

DI84 commented on Jun 24, 2025

niko-la-petrovic commented on Jul 20, 2025

github-actions commented on Aug 19, 2025

DudeNr33 commented on Aug 21, 2025

github-actions commented on Sep 21, 2025

martinthomas commented on Oct 19, 2025

LarrxX commented on May 7, 2026

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions