From: Andrew Ardill <andrew.ardill@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Christian Couder <chriscool@tuxfamily.org>,
Jeff King <peff@peff.net>, Michal Vyskocil <mvyskocil@suse.cz>,
git@vger.kernel.org, Sverre Rabbelier <srabbelier@gmail.com>,
Johannes Sixt <j6t@kdbg.org>
Subject: Re: [RFC/PATCH]: reverse bisect v 2.0
Date: Fri, 7 Oct 2011 12:57:30 +1100 [thread overview]
Message-ID: <CAH5451kUf=vPfgOOusmJjfbiyueX9VByJLzZ9WbyqLd0z78wxA@mail.gmail.com> (raw)
In-Reply-To: <7v62k4ban7.fsf@alter.siamese.dyndns.org>
Hi, I have given this some thought and have a slightly different
proposal for the options to use. I have written a commit message that
I think explains the need for the improvement, and justifies my
proposal. The options I propose are '--intoduced' and '--removed'.
--->8---
Bisect is used to look for a commit that causes a specific change.
Such a change can be classified by the user as either introducing
something, or removing something, and this distinction is arbitrary. A
change could be said to introduce a bug fix, or remove a bug - both
formulations have inherently the same meaning, but search behaviour
changes depending on which one we use.
Suppose I want to find the commit that removed a bug. If I examine a
snapshot and it contains the bug, the bug has not yet been *removed*
and I must look in the future for its removal. Conversely, if I
examine a snapshot and the bug fix exists, the bug fix must have been
*introduced* at some earlier point and so I must search backwards.
Confusion exists at this point because at each verification step a
question like 'Does this snapshot have X?' is asked, when what we
eventually want to know is 'When was X introduced?' or 'When was X
removed?'. Previously there has been no way to specify if we are
looking for X being introduced or removed; it was assumed that we were
looking for when something was introduced, for example when a bug was
introduced.
Teach git bisect if we are looking for when something was introduced
or when something was removed.
Examples.
Search for a feature add:
$ git bisect start --introduced='feature: git frotz says xyzzy' v0.99 master
Bisecting: 171 revisions left to test after this (roughly 8 steps)
$ ... build and then test ...
$ git bisect tested
Does this snapshot have 'feature: git frotz says xyzzy' [y/n]? yes
# already added, look backwards
Search for a feature regression:
$ git bisect start --removed='feature: git frotz says xyzzy' v0.99 master
Bisecting: 171 revisions left to test after this (roughly 8 steps)
$ ... build and then test ...
$ git bisect tested
Does this snapshot have 'feature: git frotz says xyzzy' [y/n]? yes
# not removed yet, look forwards
--->8---
Regards,
Andrew Ardill
next prev parent reply other threads:[~2011-10-07 1:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-29 14:20 RFC: reverse bisect Michal Vyskocil
2011-09-29 14:42 ` Sverre Rabbelier
2011-09-29 16:27 ` Johannes Sixt
2011-09-30 4:09 ` Jeff King
2011-09-30 5:31 ` Frans Klaver
2011-09-30 8:29 ` Michal Vyskocil
2011-09-30 11:42 ` [RFC/PATCH]: reverse bisect v 2.0 Michal Vyskocil
2011-09-30 18:13 ` Junio C Hamano
2011-10-03 10:41 ` Jeff King
2011-10-03 17:00 ` Junio C Hamano
2011-10-04 10:30 ` Jeff King
2011-10-04 15:22 ` Junio C Hamano
2011-10-04 22:34 ` Christian Couder
2011-10-04 23:27 ` Junio C Hamano
2011-10-07 1:57 ` Andrew Ardill [this message]
2011-10-12 4:57 ` Junio C Hamano
2011-10-12 20:14 ` Jeff King
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