While working on #18836 I run into this, which is still a problem with 7.0beta1. In summary, I define an element d of QQbar which happens to equal -5 but is constructed by finding a root in QQbar of a polynomial with coefficients in a number field. Then d.sqrt() raises an error, unless I first compute d.imag().is_zero() (which is True). There is some special casing in QQbar.sqrt for real arguments, but in this case you only know that the argument is real if you test whether the imaginary part is exactly 0.
Test code attached, It runs fine unless you comment out lines 35.36 in which case an error is raised. It's the simplest I could make it. John -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
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