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From: Elijah Newren <newren@gmail.com>
To: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>,
	Derrick Stolee <dstolee@microsoft.com>,
	Jonathan Tan <jonathantanmy@google.com>,
	Taylor Blau <me@ttaylorr.com>, Derrick Stolee <stolee@gmail.com>
Subject: Re: [PATCH v2 00/13] Optimization batch 11: avoid repeatedly detecting same renames
Date: Fri, 14 May 2021 10:37:20 -0700	[thread overview]
Message-ID: <CABPp-BGz-SGzbHAHOOjjo5FCBOgYehR0qa_rEn3saOw2gXt86g@mail.gmail.com> (raw)
In-Reply-To: <pull.859.v2.git.1620094339.gitgitgadget@gmail.com>

On Mon, May 3, 2021 at 7:12 PM Elijah Newren via GitGitGadget
<gitgitgadget@gmail.com> wrote:
>
> This series avoids repeatedly detecting the same renames in a sequence of
> merges such as a rebase or cherry-pick of several commits. It's
> unfortunately become a bit lengthy, but much of the length (the first five
> patches) is owed to special testcases and documentation.

Since this obviously hasn't inspired much review, let me note that you
can cut out 90% of the review size by skipping patches 2 & 5.

Patch 2 is essentially written as something approaching a formal
proof, so yes it's dense and lengthy, but it's not at all required;
there's no code there.  Think of it as insurance for if someone wants
to introduce some new tricky optimizations or radically different
features to the merge machinery, because the remember-renames
optimization by its nature tends to interact with other optimizations.
I figured because of that interaction that documenting why and how the
remember renames optimization works at a much deeper level than is
typical for optimizations or code in git in general that it might help
with future maintenance...and it happened to help me catch two minor
bugs.

Patch 5 is very much related to patch 2; it's testcases inspired by
that document.  Most of those tests were just "what could possibly go
wrong in a new from-scratch implementation of this optimization?"
based on what's written in this proof-like document.  Most of the
tests didn't turn up anything, but a couple found some small issues in
my implementation.  I decided to just include all of them; it's nice
to be thorough.

You can get 95% of the whole idea behind this optimization skipping
those patches and reading Junio's great two-paragraph summary at
https://lore.kernel.org/git/xmqqzgyrukic.fsf@gitster.g/, and then just
read the other patches in this series.

  parent reply	other threads:[~2021-05-14 17:37 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 21:32 [PATCH 0/7] " Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 1/7] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 2/7] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 3/7] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 4/7] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 5/7] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 6/7] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-03-24 21:32 ` [PATCH 7/7] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-03-24 22:04 ` [PATCH 0/7] Optimization batch 11: avoid repeatedly detecting same renames Junio C Hamano
2021-03-24 23:25   ` Elijah Newren
2021-03-25 18:59     ` Junio C Hamano
2021-03-29 22:34       ` Elijah Newren
2021-03-30 12:07         ` Derrick Stolee
2021-05-04  2:12 ` [PATCH v2 00/13] " Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 01/13] t6423: rename file within directory that other side renamed Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 02/13] Documentation/technical: describe remembering renames optimization Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 03/13] fast-rebase: change assert() to BUG() Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 04/13] fast-rebase: write conflict state to working tree, index, and HEAD Elijah Newren via GitGitGadget
2021-05-17 13:32     ` Derrick Stolee
2021-05-18  3:42       ` Elijah Newren
2021-05-18 13:54         ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 05/13] t6429: testcases for remembering renames Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 06/13] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-05-17 13:41     ` Derrick Stolee
2021-05-18  3:55       ` Elijah Newren
2021-05-18 13:57         ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 07/13] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-05-17 13:51     ` Derrick Stolee
2021-05-20  0:48       ` Elijah Newren
2021-05-04  2:12   ` [PATCH v2 08/13] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-05-17 14:01     ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 09/13] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-05-17 14:10     ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 10/13] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 11/13] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-05-04  2:12   ` [PATCH v2 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases Elijah Newren via GitGitGadget
2021-05-17 14:16     ` Derrick Stolee
2021-05-04  2:12   ` [PATCH v2 13/13] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-05-17 14:23     ` Derrick Stolee
2021-05-20  0:36       ` Elijah Newren
2021-05-22 11:17         ` Derrick Stolee
2021-05-14 17:37   ` Elijah Newren [this message]
2021-05-14 21:04     ` [PATCH v2 00/13] Optimization batch 11: avoid repeatedly detecting same renames Derrick Stolee
2021-05-20  6:09   ` [PATCH v3 " Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 01/13] t6423: rename file within directory that other side renamed Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 02/13] Documentation/technical: describe remembering renames optimization Elijah Newren via GitGitGadget
2021-05-20 11:32       ` Bagas Sanjaya
2021-05-20 15:14         ` Kerry, Richard
2021-05-20 16:34         ` Elijah Newren
2021-05-20  6:09     ` [PATCH v3 03/13] fast-rebase: change assert() to BUG() Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 04/13] fast-rebase: write conflict state to working tree, index, and HEAD Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 05/13] t6429: testcases for remembering renames Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 06/13] merge-ort: add data structures for in-memory caching of rename detection Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 07/13] merge-ort: populate caches of rename detection results Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 08/13] merge-ort: add code to check for whether cached renames can be reused Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 09/13] merge-ort: avoid accidental API mis-use Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 10/13] merge-ort: preserve cached renames for the appropriate side Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 11/13] merge-ort: add helper functions for using cached renames Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 12/13] merge-ort: handle interactions of caching and rename/rename(1to1) cases Elijah Newren via GitGitGadget
2021-05-20  6:09     ` [PATCH v3 13/13] merge-ort, diffcore-rename: employ cached renames when possible Elijah Newren via GitGitGadget
2021-05-22 11:17     ` [PATCH v3 00/13] Optimization batch 11: avoid repeatedly detecting same renames Derrick Stolee

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