ZheNing Hu <adlternative@xxxxxxxxx> 于2021年5月28日周五 下午11:04写道：
>
> > Can the change in this commit violate the invariant that
> > if_then_else->str cannot be NULL, which seems to have been the case
> > forever as we see an unchecked strcmp() done in the original?
> >
> > If so, perhaps you can check the condition upfront, where you
> > compute str_len above, e.g.
> >
> > if (!if_then_else->str) {
> > if (if_then_else->cmp_status == COMPARE_EQUAL ||
> > if_then_else->cmp_status == COMPARE_UNEQUAL)
> > BUG(...);
> > } else
> > str_len = strlen(...);
> >
> > If not, then I do not see the point of adding this (and later) check
> > with BUG to this code.
> >
> > Or is the invariant that .str must not be NULL could have been
> > violated without this patch (i.e. the original was buggy in running
> > strcmp() on .str without checking)? If so, please make it a separate
> > preliminary change to add such an assert.
> >
>
> The BUG() here actually acts as an "assert()". ".str must not be NULL" is
> right, it point to "xxx" in "%(if:equals=xxx)", so it seems that these BUG()
> are somewhat redundant, I will remove them.
>
Correct the error: If the atom is "%(if)" instread of
"%(if:equals=xxx)", .str will be NULL.
Without assert() or BUG() is ok, but clang-tidy will give a warning:
"Null pointer
passed to 1st parameter expecting 'nonnull'"
--
ZheNing Hu
