[Mondrian] RE: Test failures with high-cardinality dimensions
John V. Sichi
jsichi at gmail.com
Tue Jul 15 01:35:10 EDT 2008
Julian Hyde wrote:
> Looks like we have very different opinions on this issue. The way I see
> it, we have a half implemented feature. I think that most mondrian users
> would see it that way too.
> (I'd like to hear about other developers on the list feel about this.)
One of the nice things about open source is that it doesn't always have
to be either/or; it's possible to live happily in quantum superposition
for quite a long time, with a suitable approach to source control. Take
a look at the way Linux kernel development works. There's a primary
trunk which everyone wants to get their stuff into eventually, but there
are a lot of review/quality barriers to prevent half-working stuff from
getting in. Then (besides stable/release trees) there are many
experimental trees. Projects like User Mode Linux and uCLinux spent
years as experimental trees, with lots of changes all across the kernel.
The maintainers had to keep merging down everyone else's work from the
trunk, and had to keep submitting their own updated patches back
upstream; through enough perseverance, they finally got their work
included into mainstream kernels.
Experiments which lack dedicated maintainers will die a natural death
without ever doing any harm to the trunk, since they never got into it
in the first place. And even then, they may remain useful as salvage
yard for later attempts at similar features. The merge burden is placed
on the experimenters (rather than on people maintaining features already
in the trunk), which is as it should be.
This approach requires heavy use of private branching, which is
something that Julian has discouraged so far, for good reason (it's nice
to be able to see the history of a file all in one place, without
chasing changes across integrations). It also requires stringent code
review practices, which not everyone has time for. A comprehensive
performance regression suite like we've been discussing is also a
must-have as a barrier. But quality never comes cheap.
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