If mypy fails and only prints to stdout, not stderr, this leads to a cryptic event log message without details or stacktrace

Step 1: Are you in the right place?

• I have verified there are no duplicate active or recent bugs, questions, or requests
• I have verified that I am using the latest version of the plugin.

Step 2: Describe your environment

• Plugin version: 0.14.0
• PyCharm/IDEA version: 2021.3.2 (Build 213.6777.50)
• Mypy version: 0.931
• Python version: 3.10.2 <-- note python 3.10

Step 3: Describe the problem:

Steps to reproduce:

1. use a match statement
2. use the plugin to run mypy on that file

Observed Results:

Error in event log (see below)

Expected Results:

• plain error report of mypy result as with other mypy violations, instead of plugin crash
• detailed information about what caused the error

Relevant Code:

MWE:

def print_hi(name):
    match name:
        case "Mypy":
            print("Doesn't work")
        case _:
            print(f'Hi, {name}')


if __name__ == '__main__':
    print_hi('PyCharm')

Mypy Plugin (Mypy exited abnormally)

The scan failed due to an exception: Mypy failed with code 2 
com.leinardi.pycharm.mypy.exception.MypyToolException: Mypy failed with code 2
   at com.leinardi.pycharm.mypy.mpapi.MypyRunner.runMypy(MypyRunner.java:324)
   at com.leinardi.pycharm.mypy.mpapi.MypyRunner.scan(MypyRunner.java:266)
   at com.leinardi.pycharm.mypy.checker.ScanFiles.scan(ScanFiles.java:109)
   at com.leinardi.pycharm.mypy.checker.ScanFiles.checkFiles(ScanFiles.java:100)
   at com.leinardi.pycharm.mypy.checker.ScanFiles.call(ScanFiles.java:74)
   at com.leinardi.pycharm.mypy.checker.ScanFiles.call(ScanFiles.java:46)
   at com.intellij.openapi.application.impl.ApplicationImpl$2.call(ApplicationImpl.java:294)
   at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
   at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
   at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
   at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:668)
   at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:665)
   at java.base/java.security.AccessController.doPrivileged(Native Method)
   at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1.run(Executors.java:665)
   at java.base/java.lang.Thread.run(Thread.java:829)

[intgr]

If you point me to the correct file(s), I’d be happy to prepare a PR.

Thanks, any help would be welcome. The error handling logic lives in the MypyRunner.runMypy() method – see the diffs in https://github.com/leinardi/mypy-pycharm/pull/92/files

[christian-steinmeyer]

If I run mypy --show-column-numbers --follow-imports silent <FILE> from the same virtual env and directory, mypy runs, and doesn’t crash, but finds an error (Match statement not supported). Aaaaand there we go, that seems to be the issue.

In a MWE in the same environment, this yields the same error:

def print_hi(name):
    match name:
        case "Mypy":
            print("Doesn't work")
        case _:
            print(f'Hi, {name}')


if __name__ == '__main__':
    print_hi('PyCharm')