#281 Assume DB context names interfere with variables

[Stavros Macrakis]

This is a very hard bug to believe. And it was very hard to reproduce, because it only bites under very particular circumstances.

block([context:b],assume(b>c,c>a),sign(b-c));

returns neg, which is incorrect.

The name of the context is important. It must be the same as the larger variable.

The context name may be quoted (context:'b) or not -- it doesn't matter.

There must be TWO assumptions, with related variables. But the order doesn't matter.

So apparently the context name is somehow getting mixed up with the variables within the context.

[Stavros Macrakis]

Logged In: YES
user_id=588346

Oh, yes, I should mention that to be sure that there are no
extraneous issues, I did the testing each time in a completely
fresh Maxima (restarted, not just Kill(all)).

Maxima 5.9.0 GCL 2.5.0 mingw32 Windows 2000

[Robert Dodier]

Observed in 5.45.1. Sometimes these things get fixed incidental to other things ... no such luck for this item, it looks like.