Pylint throws error "TypeError: Converting circular structure to JSON" when using pylint + any combination of other linters.

[crhan]

Environment data

• VS Code version: 1.30.0
• Extension version (available under the Extensions sidebar): 2018.12.0
• OS and version: MacOS 10.14.2 (18C54)
• Python version (& distribution if applicable, e.g. Anaconda): python 3.6.6
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): venv
• Relevant/affected Python packages and their versions:

pylint 2.2.2
astroid 2.0.4
Python 3.6.6 (default, Sep 17 2018, 16:44:58)
[GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.2)]

Extension infomation:

Name: Python
Id: ms-python.python
Description: Linting, Debugging (multi-threaded, remote), Intellisense, code formatting, refactoring, unit tests, snippets, and more.
Version: 2018.12.0
Publisher: Microsoft
VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=ms-python.python

Expected behaviour

Pylint work as it was

Actual behaviour

Steps to reproduce:

1. Upgrade vscode python extension to 2018.12.0
2. open any python file

Logs

Starting Microsoft Python language server.
Linting with mypy failed.
TypeError: Converting circular structure to JSON
Linting with pylint failed.
TypeError: Converting circular structure to JSON
##########Linting Output - bandit##########
94,0,MEDIUM,B104:Possible binding to all interfaces.
173,0,LOW,B101:Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.
188,0,LOW,B101:Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.
189,0,LOW,B101:Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.
Microsoft Python Language Server version 0.1.72.0
Initializing for /Users/ruohan.chen/.pyenv/versions/vpc_test-3.6.6/bin/python

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

[Extension Host] [modelines] could not find TextEditor
console.ts:134 [Extension Host] Python Extension: There was an error in running the linter mypy TypeError: Converting circular structure to JSON
	at JSON.stringify (<anonymous>)
	at module.exports.t.ProcessService.getDefaultOptions (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:315447)
	at module.exports.t.ProcessService.exec (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:314478)
	at p.<anonymous> (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:326851)
	at Generator.next (<anonymous>)
	at module.exports.i (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:324782)
	at new Promise (<anonymous>)
	at module.exports.i (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:324559)
	at p.execModule (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:326765)
	at u.<anonymous> (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:328639)
	at Generator.next (<anonymous>)
	at s (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:327651)
	at <anonymous>
t.log @ console.ts:134
notificationsAlerts.ts:40 There was an error in running the linter 'mypy'
t.onDidNotificationChange @ notificationsAlerts.ts:40
console.ts:134 [Extension Host] Python Extension: There was an error in running the linter pylint TypeError: Converting circular structure to JSON
	at JSON.stringify (<anonymous>)
	at module.exports.t.ProcessService.getDefaultOptions (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:315447)
	at module.exports.t.ProcessService.exec (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:314478)
	at p.<anonymous> (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:326851)
	at Generator.next (<anonymous>)
	at module.exports.i (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:324782)
	at new Promise (<anonymous>)
	at module.exports.i (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:324559)
	at p.execModule (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:326765)
	at u.<anonymous> (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:328639)
	at Generator.next (<anonymous>)
	at s (/Users/ruohan.chen/.vscode/extensions/ms-python.python-2018.12.0/out/client/extension.js:83:327651)
	at <anonymous>
t.log @ console.ts:134
notificationsAlerts.ts:40 There was an error in running the linter 'pylint'
t.onDidNotificationChange @ notificationsAlerts.ts:40
console.ts:134 [Extension Host] [modelines] setting editor options: {}

[Gr1N]

Same issue

[d3r3kk]

I verified this bug and found that you can reproduce this issue with pylint + any combination of other linters being used in tandem with pylint, it is not necessary to use all other linters described.

[matthieugouel]

I have the same problem using flake8 and mypy which both fails the same way (but bandit not) but I don't use pylint. Only on version 2018.12.0.

Starting Jedi Python language engine.
Linting with mypy failed.
TypeError: Converting circular structure to JSON
Linting with flake8 failed.
TypeError: Converting circular structure to JSON
##########Linting Output - bandit##########

[pierrecregut]

In src/client/common/process/proc.ts:

    private getDefaultOptions<T extends (ShellOptions | SpawnOptions)>(options: T) : T {
        const execOptions = options as SpawnOptions;
        const defaultOptions = JSON.parse(JSON.stringify(options));

It fails because options has a token field that contains a circular structure. A crude patch:

        const safeOptions = Object.assign({}, options);
        delete safeOptions.token
        const defaultOptions = JSON.parse(JSON.stringify(safeOptions));

[iansan5653]

I just started having the same problem this morning.

Starting Microsoft Python language server.
##########Linting Output - bandit##########
Linting with flake8 failed.
TypeError: Converting circular structure to JSON
Linting with flake8 failed.
TypeError: Converting circular structure to JSON
##########Linting Output - bandit##########
Linting with flake8 failed.
...

[iansan5653]

It looks like PR #3702 would fix this

[iansan5653]

A temporary fix is to disable all but one linter. In my case, setting python.linting.banditEnabled to false fixed the problem (but of course then you're not using your other linter, so it's just a quick fix to avoid the error until it's patched).

[d3r3kk]

Thanks for the clarification @matthieugouel, and the legwork @pierrecregut!

(It was a sleepless night at 3am for me when I made my observation, so awesome to wake up to this info!)