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From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: David Turner <dturner@twopensource•com>,
	Elijah Newren <newren@gmail•com>,
	git mailing list <git@vger•kernel.org>
Subject: Re: git reset for index restoration?
Date: Thu, 22 May 2014 15:29:24 -0700	[thread overview]
Message-ID: <xmqqwqddla63.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <xmqq61kxmphw.fsf@gitster.dls.corp.google.com> (Junio C. Hamano's message of "Thu, 22 May 2014 15:12:59 -0700")

Junio C Hamano <gitster@pobox•com> writes:

> But at least my understanding has been that "git commit" (no partial
> commit, write the whole index as a commit) which uses the "git
> write-tree" machinery knows which subtree has what tree object name
> and populates the cache-tree fully.

Here is what I tried just now.

    $ rm .git/index
    $ git read-tree HEAD HEAD

Note that a single-tree read-tree will populate the cache-tree and
that is why I am forcing "switch branches" 2-way read-tree here,
which I know will discard the cache-tree fully.

    $ ls -l .git/index
    -rw-r----- 1 jch eng 249440 May 22 15:20 .git/index
    $ git checkout HEAD^0
    $ ls -l .git/index
    -rw-r----- 1 jch eng 249440 May 22 15:21 .git/index

Still the same size, without cache-tree.

    $ git write-tree
    57361c4add61b638dad1c1c2542edf877f515c48
    $ ls -l .git/index
    -rw-r----- 1 jch eng 254383 May 22 15:21 .git/index

The size differences come from the recomputation of the cache tree.
The result is the same if we replace "git write-tree" with a
whole-index commit, e.g.

    $ git commit --allow-empty -m foo

and test-dump-cache-tree seem to see a fully populated cache-tree
after these steps.

  parent reply	other threads:[~2014-05-22 22:29 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-22 16:22 git reset for index restoration? David Turner
2014-05-22 16:46 ` Jeff King
2014-05-22 18:08   ` David Turner
2014-05-22 18:23     ` Jeff King
2014-05-22 19:26       ` David Turner
2014-05-22 16:46 ` Elijah Newren
2014-05-22 18:17   ` David Turner
2014-05-22 18:39     ` Jeff King
2014-05-22 19:07       ` David Turner
2014-05-22 19:09         ` Jeff King
2014-05-22 19:30           ` Jeff King
2014-05-22 21:34             ` Junio C Hamano
2014-05-22 21:53               ` David Turner
2014-05-22 21:58                 ` Junio C Hamano
2014-05-22 22:01                   ` David Turner
2014-05-22 22:12                     ` Junio C Hamano
2014-05-22 22:18                       ` Junio C Hamano
2014-05-22 23:33                         ` Duy Nguyen
2014-05-22 23:37                           ` David Turner
2014-05-22 22:29                       ` Junio C Hamano [this message]
2014-05-22 23:02                         ` David Turner
2014-05-22 23:14                           ` Junio C Hamano

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