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gh-94808: Remove unused code in _make_posargs #119227
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Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool. If this change has little impact on Python users, wait for a maintainer to apply the |
The current code covers all combinations of plain_names & names_with_default being NULL and non-NULL. Removing one of the cases breaks that, leaving no hint about why this would fall through to the empty // With the current grammar, we never get here.
// When that changes, remove the assert, and test thoroughly.
assert(0);
*posargs = plain_names; |
I agree, that's better. Should I resubmit? |
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This looks good to me, thanks! |
Thanks! I meant to wrap this up over the weekend, but forgot. I will do it this week. |
`names_with_default` is never `NULL`, even if there are no names with defaults. In that case it points to a structure with `size` zero. Rather than eliminating the branch, we leave it behind with an `assert(0)` in case a future change to the grammar exercises the branch.
@encukou I split the changes into two commits, one to improve coverage and the other to reorganize the if-else structure. |
Thanks! For the future: please avoid force-pushing to CPython -- when reviewed commits disappear, the review needs to be restarted. (In this commit it's not a problem, as it's just a few lines.) |
Thanks again for your help and guidance through the whole process. |
…GH-119227) * Reorganize four-way if-elsif-elsif-elsif as nested if-elses * Mark unused branch in _make_posargs `names_with_default` is never `NULL`, even if there are no names with defaults. In that case it points to a structure with `size` zero. Rather than eliminating the branch, we leave it behind with an `assert(0)` in case a future change to the grammar exercises the branch.
…GH-119227) * Reorganize four-way if-elsif-elsif-elsif as nested if-elses * Mark unused branch in _make_posargs `names_with_default` is never `NULL`, even if there are no names with defaults. In that case it points to a structure with `size` zero. Rather than eliminating the branch, we leave it behind with an `assert(0)` in case a future change to the grammar exercises the branch.
…GH-119227) * Reorganize four-way if-elsif-elsif-elsif as nested if-elses * Mark unused branch in _make_posargs `names_with_default` is never `NULL`, even if there are no names with defaults. In that case it points to a structure with `size` zero. Rather than eliminating the branch, we leave it behind with an `assert(0)` in case a future change to the grammar exercises the branch.
The coverage report indicates that this branch is never exercised. That appears to be because it is unused code. When I couldn't produce a test case that exercised it, I removed the branch, then checked that the complete test suite still passed.
The branch is only run when
names_with_default
is null. It appears that when there are no names with defaults,names_with_defaults
will point to a structure that has.size
zero.It's possible that a future implementation change might alter that, requiring the branch to be put back, but I believe the existing tests would detect if that happened.