[Yum-devel] rangeCompare() incorrectly discards Epoch from provides

[Ville Skyttä]

Hello,

This is the post I referred to in my previous compareEVR() patch explanation.
See the attached patch (just for discussion purposes for now).

First, pay attention to the added testcase in packagetests.py:

(('foo', 'LT', (None, '1.4.4', None)), ('foo', 'EQ', ('3', '1.2.4', '7')),  0)

In human readable form, "Requires: foo < 1.4.4" should _not_ be satisfied by 
"Provides: foo = 3:1.2.4-7" (or the corresponding NEVR).  Now, I'm not aware 
of a case where this would actually fail completely within yum which may 
coerce None Epochs to '0' in all paths that lead to calling rangeCompare() 
thus circumventing the issue, but it sure does fail if one looks at it as a  
API function, and it also actually does fail for me in rpmlint where I've 
pretty much copy-pasted the corresponding functions (to avoid a yum 
dependency), and None Epochs are not coerced to 0 before calling them.

So, the simple (and correct, I still believe) approach I thought of was to 
never touch the Epoch of the provides side, which is there as the first hunk 
of the attached patch.  This fixes the above case, but causes failures in 
cases where a requires tuple with its flags != None but EVR = (None, None, 
None) gets passed to the rangeCompare checks (see comments in the attached 
patch).  I don't think I've ever seen such a dependency, and it doesn't make 
sense to me so I don't know how to start fixing the now failing test cases, 
except by simply removing the last 10 (undefined behavior if you ask me, or 
can you provide examples where such reqtuples are valid and need to be 
supported?) and digging into the first three for which I have a hunch this 
patch just reveals a bug in the test suite and does not introduce one in the 
actual yum code.

Regarding the previous compareEVR() patch I sent, after the provides side is 
no longer touched as a result of the attached patch, a lot of other test cases 
(not only rangeCompare()) started failing, and that patch got those fixed.
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