Support branch coverage

[lackhove]

fixes #5

[lackhove]

@cdleonard This feature should be working now. The shell-based project I used for testing is finished and I no longer have access to it. Could you maybe take this for a spin and see if anything breaks or seems off?

[cdleonard]

Used this in a few private projects and it seems fine.

I did however find a new unrelated issue: #48

[cdleonard]

I did eventually find a failure specific to branch coverage (doesn't fail otherwise):

#! /bin/bash

fun()
{
    if [[ -z $myvar ]]; then
        echo "Missing myvar?" >&2
        exit 1
    fi
}

myvar=1 fun

Relevant part of log:

INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/pytest_cov/plugin.py", line 362, in pytest_runtestloop
INTERNALERROR>     self.cov_total = self.cov_controller.summary(self.cov_report)
INTERNALERROR>                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/pytest_cov/engine.py", line 44, in ensure_topdir_wrapper
INTERNALERROR>     return meth(self, *args, **kwargs)
INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/pytest_cov/engine.py", line 189, in summary
INTERNALERROR>     self.cov.html_report(ignore_errors=True, directory=output)
INTERNALERROR>     ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/coverage/control.py", line 1259, in html_report
INTERNALERROR>     return reporter.report(morfs)
INTERNALERROR>            ~~~~~~~~~~~~~~~^^^^^^^
INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/coverage/html.py", line 392, in report
INTERNALERROR>     self.write_html_page(ftr)
INTERNALERROR>     ~~~~~~~~~~~~~~~~~~~~^^^^^
INTERNALERROR>   File "/home/leonard/Projects/test-python-coverage-sh/sample/.venv/lib/python3.13/site-packages/coverage/html.py", line 527, in write_html_page
INTERNALERROR>     assert len(longs) == 1, (
INTERNALERROR>            ^^^^^^^^^^^^^^^
INTERNALERROR> AssertionError: Had long annotations in fail_jump_in_func.sh: ["Line 5 didn't jump to line 6", "Line 5 didn't jump to line 7"]