Multiline asserts need too many pragma: no covers

[nedbat]

Originally reported by Barry Warsaw (Bitbucket: warsaw, GitHub: warsaw)

---

Code like the following:

#!python

        assert command_class.name not in config.commands, (  # pragma: no cover
            'Duplicate email command "{}" found in {}'.format( # pragma: no cover
                command_class.name,                            # pragma: no cover
                command_class.__module__))

Note the pragma: no cover on every line. I want to completely ignore the entire assert statement, but w/o all those pragmas, I get a report that some of those lines aren't covered, which is true, but unhelpful!

---

• Bitbucket: https://bitbucket.org/ned/coveragepy/issue/461

[nedbat]

@warsaw can you provide a complete runnable example? Is the statement not covered because of -O?

[nedbat]

This was my attempt to reproduce it:

$ cat bug461.py
a = 1
assert not a, (
      'Duplicate email command "{}" found in {}'.format(
                len([]),
                len([1])))
b = 2
print(a, b)
$ PYTHONOPTIMIZE=1 coverage run bug461.py
(1, 2)
$ coverage report -m
Name        Stmts   Miss  Cover   Missing
-----------------------------------------
bug461.py       4      1    75%   2
$ vim bug461.py
$ cat bug461.py
a = 1
assert not a, (                                             # pragma: no cover
      'Duplicate email command "{}" found in {}'.format(
                len([]),
                len([1])))
b = 2
print(a, b)
$ PYTHONOPTIMIZE=1 coverage run bug461.py
(1, 2)
$ coverage report -m
Name        Stmts   Miss  Cover   Missing
-----------------------------------------
bug461.py       3      0   100%

Here only line 2 is considered a statement, and a single pragma was enough to quiet it.

[nedbat]

Original comment by Barry Warsaw (Bitbucket: warsaw, GitHub: warsaw)

---

That's interesting. In my larger test case, I'm not running with -O, and it seems like all four lines in the assert are being counted (and thus all four need pragma: no cover). I'll have to see if I can boil down to a smaller reproducible test case.

[nedbat]

If it doesn't reduce down, you can give me instructions how to run the larger test case.

[nedbat]

Original comment by Barry Warsaw (Bitbucket: warsaw, GitHub: warsaw)

---

Hi Ned, thanks for the help. You should be able to reproduce like so:

#!

$ git clone https://gitlab.com/mailman/mailman.git
$ cd mailman
$ tox -e coverage

You might have to change basepython to python3.4 in tox.ini if you don't have Python 3.5. I'm fairly certain it's not a Python 3.4/3.5 thing, but I can check that.

There are several cases where multiline asserts are being treated as multiple statements and being reported as not covered. src/mailman/app/commands.py is a good example. Note that I tried # pragma: no cover on these lines, but the current git head uses an exclude_lines in coverage.ini, which the tox.ini arranges to be used.

[nedbat]

OK, I've reproduced your results in your repo, thanks. Now to figure out why it's different than my test case....

[nedbat]

Turns out this is another instance of http://bugs.python.org/issue19035: form-feeds look like end-of-file. @warsaw is it possible you are the only person still using form-feeds? :) :)

I'll make a fix soon.

[nedbat]

Original comment by Barry Warsaw (Bitbucket: warsaw, GitHub: warsaw)

---

Oh gosh. Too funny, and yeah probably so! I really should get rid of those, but it's a lot of legacy code to go through. Thanks for working on the fix! (I should take a crack at the Python bug.)

[nedbat]

Fixed in b3a775b34648 (bb), which will be in 4.1.

[nedbat]

Original comment by Barry Warsaw (Bitbucket: warsaw, GitHub: warsaw)

---

Thanks!