From: Junio C Hamano <gitster@pobox•com>
To: Alan Stern <stern@rowland•harvard.edu>
Cc: Jonathan Nieder <jrnieder@gmail•com>, <git@vger•kernel.org>
Subject: Re: Reachability lists in git
Date: Tue, 18 Nov 2014 13:22:26 -0800 [thread overview]
Message-ID: <xmqq1tp0uru5.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1411181610070.2918-100000@iolanthe.rowland.org> (Alan Stern's message of "Tue, 18 Nov 2014 16:16:57 -0500 (EST)")
Alan Stern <stern@rowland•harvard.edu> writes:
>> > No. Here's a simple example:
>> >
>> > Y
>> > /
>> > /
>> > X--B
>> >
>> > In this diagram, X = B^. But B isn't reachable from either X or Y,
>> > whereas it is reachable from one of X's children (namely Y).
> ...
> Thus, if B introduced a bug, that bug would not be present in Y. But Y
> might be better for testing than X, because Y might fix some other
> problems that are present in X.
The problem with that line of reasoning is that in real life there
will be unbound number of Y's that forked from a point before
somebody wrote B. Which one among these Y's would you pick and why?
If Y has fixed another problem that is present in X and make it
easier to test, Z, a direct descendant of Y (i.e. Z^1 = Y), may have
fixed yet another problem that is unrelated to the problem B
introduced and it may make the result even easier to test. Where do
you stop?
Still confused...
next prev parent reply other threads:[~2014-11-18 21:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 19:03 Reachability lists in git Alan Stern
2014-11-18 19:41 ` Jonathan Nieder
2014-11-18 20:13 ` Junio C Hamano
2014-11-18 20:22 ` Jonathan Nieder
2014-11-18 20:27 ` Jonathan Nieder
2014-11-18 20:33 ` Junio C Hamano
2014-11-18 20:29 ` Alan Stern
2014-11-18 20:32 ` Jonathan Nieder
2014-11-18 20:45 ` Alan Stern
2014-11-18 21:05 ` Junio C Hamano
2014-11-18 21:11 ` Junio C Hamano
2014-11-18 21:16 ` Alan Stern
2014-11-18 21:22 ` Junio C Hamano [this message]
2014-11-18 21:37 ` Alan Stern
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