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Re: Proposal for the transition timetable for the move to GIT


Bernd Schmidt <bernds_cb1@t-online.de>:
> I was on the fence for a long time, since I felt that the rewritten
> reposurgeon was still somewhat unproven.

And that was a fair criticism for a short while, until the first compare-all
verification on the GCC history came back clean.

The most difficult point in the whole process for me was in late
November.  That was when I faced up to the fact that, while I had a
Subversion dump reader that was 95% good, (1) that 5% could
disqualify it for this complex a history, and (2) I wasn't going to
be able to solve that last 5% without tearing down most of the reader
and rebuilding it.

The problem was that I'd been patching the dump reader to fix edge
cases for too long, and the code had rigidified. Too many auxiliary
data structures with partially overlapping semabtics - I couldn't
change anything without breaking everything. Which is the universe's
way of telling you it's time for a rewrite.

Of course the risk was that I wouldn't get that rewrite done in time
for deadline. But I had two assets that mitigated the risk. One was
a couple of very sharp collaborators, Julien Rivaud and Daniel Brooks
(and later another, Edward Cree). The other was having a really good
test suite, and a well-established procedure for integrating new
tests that jsm and rearnshaw were able to use.

It was (as the Duke of Wellington famously said) a damned near-run
thing. With all those advantages, if I had waited even a week longer
to make the crucial scrap-and-rebuild decision, the new reader might
have landed too late.

There's a lesson in here somewhere. When I figure out what it is, I'll
put it in my next book.
-- 
		<a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>



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