Exceptions that inherit from BaseException should not be treated as Uncaught Exceptions

[danielniccoli]

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Environment data

• debugpy version: 1.8.1
• OS and version: Windows 11
• Python version: 3.11
• Using VS Code or Visual Studio: VS Code

Actual behavior

exit(1) halts the debugging session due to an "uncaught exception"

Expected behavior

The program program should exit without the debugger halting.

Exceptions that inherit from exception.BaseException should not fall under the category of "uncaught exceptions", since they are "technically not an error"¹.

exception.BaseException

The base class for all built-in exceptions. It is not meant to be directly inherited by user-defined classes (for that, use Exception).

https://docs.python.org/3/library/exceptions.html#BaseException

One of these exceptions is exception.SystemExit, which is called when calling exit(1).

exception SystemExit

This exception is raised by the sys.exit() function. It inherits from BaseException instead of Exception so that it is not accidentally caught by code that catches Exception. This allows the exception to properly propagate up and cause the interpreter to exit. When it is not handled, the Python interpreter exits; no stack traceback is printed.

https://docs.python.org/3/library/exceptions.html#SystemExit

There are only three other Exceptions that inherit from exception.BaseException, not counting exception.Exception, which does fall under the category of "Uncaught Exceptions":

BaseException
 ├── BaseExceptionGroup
 ├── GeneratorExit
 ├── KeyboardInterrupt
 ├── SystemExit
 └── Exception

https://docs.python.org/3/library/exceptions.html#exception-hierarchy

exception KeyboardInterrupt

Raised when the user hits the interrupt key (normally Control-C or Delete). During execution, a check for interrupts is made regularly. The exception inherits from BaseException so as to not be accidentally caught by code that catches Exception and thus prevent the interpreter from exiting.

exception GeneratorExit

Raised when a generator or coroutine is closed; see generator.close() and coroutine.close(). It directly inherits from BaseException instead of Exception since it is technically not an error.

Footnotes

1. https://docs.python.org/3/library/exceptions.html#GeneratorExit ↩

[rchiodo]

Transferring to dicussions for up votes