[Yum-devel] [Kitchen-devel] str_eq within yum (and kitchen)

[Toshio Kuratomi]

On Tue, Aug 24, 2010 at 06:28:06PM -0400, David Malcolm wrote:
> Profiling of a Fedora 14 "yum install *" showed it spending 80 seconds
> out of 274 within its implementation of "str_eq" (24 million calls), so
> optimizing this seems worthwhile.
> 
> One possibility is to hand-optimize this in C, or use Cython.
> 
> As a first step, attached are some more selftests for kitchen's [1]
> implementation of this function, to try to better capture some of the
> expected behavior.
> 
I reworked these to use the standard data that's part of that particular
test class and reorganized them to put the emphasis on bytes vs unicode
instead of ascii vs non-ascii which just confuses things.

Thanks for organizing the matrix of what to test.

> 
> What's the expected behavior, if any, of passing in objects that aren't
> str or unicode?
> 
> e.g. passing in a float
> >>> str_eq(0.1, 0.1)
> True
> 
> Is it acceptable if, say it, raises a TypeError instead?
> 
> Do you need support for objects that are derived from str/unicode as
> well as those specific classes?
> 
I'm not sure what the expected behaviour for yum is.  For the to_bytes and
to_unicode kitchen code, this is configurable with the default being to
return the simplerepr (basically, str but without throwing an error if
there's a problem).

I'm not sure that's what we want to do here, though -- str_eq is not
explicitly a converter between bytes and unicode.  It's a test for equality.
Two objects could return the same (or different) simplereprs and still be
different (or the same).  So TypeError seems like a better default.
However, throwing a TypeError requires more isinstance calls which may be
counter to your goal of speeding this up.

Right now, I'd say the behaviour of passing in non-basestring objects could
be documented as undefined.

-Toshio
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