Pattern matching with branch coverage shows missing exit

[thtrummer]

Describe the bug
Using pattern matching with branch coverage shows missing exit.

Name         Stmts   Miss Branch BrPart  Cover   Missing
--------------------------------------------------------
example.py       8      0      4      1    92%   5->exit
--------------------------------------------------------
TOTAL            8      0      4      1    92%

To Reproduce

Answer the questions below:

1. What version of Python are you using?
   Python 3.13.5
2. What version of coverage.py shows the problem? The output of coverage debug sys is helpful.
   Coverage.py, version 7.10.6 with C extension
3. What versions of what packages do you have installed? The output of pip freeze is helpful.
   coverage==7.10.6
4. What code shows the problem? Give us a specific commit of a specific repo that we can check out. If you've already worked around the problem, please provide a commit before that fix.

def fn(value):
    match value:
        case int():
            print('int')
        case str():
            print('str')

fn(1)
fn('hello')

5. What commands should we run to reproduce the problem? Be specific. Include everything, even git clone, pip install, and so on. Explain like we're five!

coverage run --branch example.py
coverage report -m

Expected behavior
100% coverage

[nedbat]

In this case, I think coverage.py is right: there is a path through this code that you never tested: what if value is neither an int or a str?

[thtrummer]

I was considering this and compared it to an if isinstance version which shows 100% coverage. Though, if you use an if-else construct (which is closer to the match-case version) it shows the same behavior, so I am not sure anymore.

def fn1(value):
    match value:
        case int():
            print('int')
        case str():  # Line 5
            print('str')

def fn2(value):
    if isinstance(value, int):
        print('int')
    elif isinstance(value, str):  # Line 11
        print('str')

def fn3(value):
    if isinstance(value, int):
        print('int')
    if isinstance(value, str):
        print('str')

Name           Stmts   Miss Branch BrPart  Cover   Missing
----------------------------------------------------------
example.py        22      0     12      2    94%   5->exit, 11->exit
----------------------------------------------------------
TOTAL             22      0     12      2    94%