git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Victoria Dye <vdye@github.com>
To: phillip.wood@dunelm.org.uk,
	Victoria Dye via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org
Cc: stolee@gmail.com, gitster@pobox.com, newren@gmail.com,
	"Taylor Blau" <me@ttaylorr.com>,
	"Bagas Sanjaya" <bagasdotme@gmail.com>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH v3 6/8] reset: make sparse-aware (except --mixed)
Date: Fri, 8 Oct 2021 13:14:13 -0400	[thread overview]
Message-ID: <52768318-ef8a-b26f-d4bc-d5c91779ccdb@github.com> (raw)
In-Reply-To: <c1dd1fef-2d48-cc18-5786-10e174b487a7@gmail.com>

Phillip Wood wrote:
> Hi Victoria
> 
> On 07/10/2021 22:15, Victoria Dye via GitGitGadget wrote:
>> From: Victoria Dye <vdye@github.com>
>>
>> Remove `ensure_full_index` guard on `prime_cache_tree` and update
>> `prime_cache_tree_rec` to correctly reconstruct sparse directory entries in
>> the cache tree. While processing a tree's entries, `prime_cache_tree_rec`
>> must determine whether a directory entry is sparse or not by searching for
>> it in the index (*without* expanding the index). If a matching sparse
>> directory index entry is found, no subtrees are added to the cache tree
>> entry and the entry count is set to 1 (representing the sparse directory
>> itself). Otherwise, the tree is assumed to not be sparse and its subtrees
>> are recursively added to the cache tree.
> 
> I was looking at the callers to prime_cache_tree() this morning and would like to suggest an alternative approach - just delete prime_cache_tree() and all of its callers! As far as I can see it is only ever called after a successful call to unpack_trees() and since 52fca2184d ("unpack-trees: populate cache-tree on successful merge", 2015-07-28) unpack_trees() updates the cache tree for the caller. All the call sites are pretty obvious apart from the one in t/help/test-fast-rebase.c where unpack_trees() is called by merge_switch_to_result()
> 

It looks like `prime_cache_tree` can be removed mostly without issue, but
it causes the two last tests in `t4058-diff-duplicates.sh` to fail. Those
tests document failure cases when dealing with duplicate tree entries [1],
and it looks like `prime_cache_tree` was creating the appearance of a
fully-reset index but was still leaving it in a state where subsequent
operations could fail.

I'm inclined to say the solution here would be to update the tests to
document the "new" failure behavior and proceed with removing
`prime_cache_tree`, because:

* the test using `git reset --hard` disables `GIT_TEST_CHECK_CACHE_TREE`,
  indicating that `prime_cache_tree` already wasn't behaving correctly
* attempting to fix the overarching issues with duplicate tree entries will
  substantially delay this patch series
* a duplicate entry fix is largely unrelated to the intended scope of the
  series

Another option would be to leave `prime_cache_tree` as it is, but with it
being apparently useless outside of mostly-broken use cases in `t4058`, it
seems like a waste to keep it around.

[1] ac14de13b2 (t4058: explore duplicate tree entry handling in a bit more detail, 2020-12-11)

  reply	other threads:[~2021-10-08 17:14 UTC|newest]

Thread overview: 114+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-30 14:50 [PATCH 0/7] Sparse Index: integrate with reset Victoria Dye via GitGitGadget
2021-09-30 14:50 ` [PATCH 1/7] reset: behave correctly with sparse-checkout Kevin Willford via GitGitGadget
2021-09-30 18:34   ` Junio C Hamano
2021-10-01 14:55     ` Victoria Dye
2021-09-30 14:50 ` [PATCH 2/7] sparse-index: update command for expand/collapse test Victoria Dye via GitGitGadget
2021-09-30 19:17   ` Taylor Blau
2021-09-30 20:11     ` Victoria Dye
2021-09-30 21:32       ` Junio C Hamano
2021-09-30 22:59         ` Victoria Dye
2021-10-01  0:04           ` Junio C Hamano
2021-10-04 13:47             ` Victoria Dye
2021-10-01  9:14   ` Bagas Sanjaya
2021-09-30 14:50 ` [PATCH 3/7] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-09-30 14:50 ` [PATCH 4/7] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-09-30 14:50 ` [PATCH 5/7] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-09-30 14:51 ` [PATCH 6/7] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-10-01 15:03   ` Victoria Dye
2021-09-30 14:51 ` [PATCH 7/7] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-10-05 13:20 ` [PATCH v2 0/7] Sparse Index: integrate with reset Victoria Dye via GitGitGadget
2021-10-05 13:20   ` [PATCH v2 1/7] reset: behave correctly with sparse-checkout Kevin Willford via GitGitGadget
2021-10-05 19:30     ` Junio C Hamano
2021-10-05 21:59       ` Victoria Dye
2021-10-06 12:44         ` Junio C Hamano
2021-10-06  1:46     ` Elijah Newren
2021-10-06 20:09       ` Victoria Dye
2021-10-06 10:31     ` Bagas Sanjaya
2021-10-05 13:20   ` [PATCH v2 2/7] update-index: add --force-full-index option for expand/collapse test Victoria Dye via GitGitGadget
2021-10-06  2:00     ` Elijah Newren
2021-10-06 20:40       ` Victoria Dye
2021-10-08  3:42         ` Elijah Newren
2021-10-08 17:11           ` Junio C Hamano
2021-10-06 10:33     ` Bagas Sanjaya
2021-10-05 13:20   ` [PATCH v2 3/7] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-10-06  2:04     ` Elijah Newren
2021-10-05 13:20   ` [PATCH v2 4/7] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-10-06  2:15     ` Elijah Newren
2021-10-06 17:48       ` Junio C Hamano
2021-10-05 13:20   ` [PATCH v2 5/7] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-10-06  3:43     ` Elijah Newren
2021-10-06 20:56       ` Victoria Dye
2021-10-06 10:34     ` Bagas Sanjaya
2021-10-05 13:20   ` [PATCH v2 6/7] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-10-06  4:43     ` Elijah Newren
2021-10-07 14:34       ` Victoria Dye
2021-10-05 13:20   ` [PATCH v2 7/7] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-10-06 10:37     ` Bagas Sanjaya
2021-10-05 15:34   ` [PATCH v2 0/7] Sparse Index: integrate with reset Ævar Arnfjörð Bjarmason
2021-10-05 20:44     ` Victoria Dye
2021-10-06  5:46   ` Elijah Newren
2021-10-07 21:15   ` [PATCH v3 0/8] " Victoria Dye via GitGitGadget
2021-10-07 21:15     ` [PATCH v3 1/8] reset: rename is_missing to !is_in_reset_tree Victoria Dye via GitGitGadget
2021-10-07 21:15     ` [PATCH v3 2/8] reset: preserve skip-worktree bit in mixed reset Kevin Willford via GitGitGadget
2021-10-08  9:04       ` Junio C Hamano
2021-10-07 21:15     ` [PATCH v3 3/8] update-index: add --force-full-index option for expand/collapse test Victoria Dye via GitGitGadget
2021-10-08  2:50       ` Bagas Sanjaya
2021-10-08  5:24       ` Junio C Hamano
2021-10-08 15:47         ` Victoria Dye
2021-10-08 17:19           ` Junio C Hamano
2021-10-11 14:12             ` Derrick Stolee
2021-10-11 15:05               ` Victoria Dye
2021-10-11 15:24               ` Junio C Hamano
2021-10-07 21:15     ` [PATCH v3 4/8] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-10-07 21:15     ` [PATCH v3 5/8] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-10-07 21:15     ` [PATCH v3 6/8] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-10-08 11:09       ` Phillip Wood
2021-10-08 17:14         ` Victoria Dye [this message]
2021-10-08 18:31           ` Junio C Hamano
2021-10-09 11:18             ` Phillip Wood
2021-10-10 22:03               ` Junio C Hamano
2021-10-11 15:55                 ` Victoria Dye
2021-10-11 16:16                   ` Junio C Hamano
2021-10-12 10:16                 ` Phillip Wood
2021-10-12 19:15                   ` Junio C Hamano
2021-10-12 10:17           ` Phillip Wood
2021-10-07 21:15     ` [PATCH v3 7/8] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-11-20 22:02       ` Elijah Newren
2021-11-22 16:46         ` Victoria Dye
2021-10-07 21:15     ` [PATCH v3 8/8] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-10-11 20:30     ` [PATCH v4 0/8] Sparse Index: integrate with reset Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 1/8] reset: rename is_missing to !is_in_reset_tree Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 2/8] reset: preserve skip-worktree bit in mixed reset Victoria Dye via GitGitGadget
2021-10-22  4:19         ` Emily Shaffer
2021-10-25 15:59           ` Victoria Dye
2021-10-11 20:30       ` [PATCH v4 3/8] sparse-index: update command for expand/collapse test Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 4/8] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 5/8] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 6/8] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 7/8] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-10-11 20:30       ` [PATCH v4 8/8] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-10-27 14:39       ` [PATCH v5 0/8] Sparse Index: integrate with reset Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 1/8] reset: rename is_missing to !is_in_reset_tree Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 2/8] reset: preserve skip-worktree bit in mixed reset Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 3/8] sparse-index: update command for expand/collapse test Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 4/8] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 5/8] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 6/8] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-10-27 14:39         ` [PATCH v5 7/8] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-11-20 22:05           ` Elijah Newren
2021-11-22 16:54             ` Victoria Dye
2021-10-27 14:39         ` [PATCH v5 8/8] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-11-20 22:13         ` [PATCH v5 0/8] Sparse Index: integrate with reset Elijah Newren
2021-11-29 15:52         ` [PATCH v6 " Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 1/8] reset: rename is_missing to !is_in_reset_tree Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 2/8] reset: preserve skip-worktree bit in mixed reset Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 3/8] sparse-index: update command for expand/collapse test Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 4/8] reset: expand test coverage for sparse checkouts Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 5/8] reset: integrate with sparse index Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 6/8] reset: make sparse-aware (except --mixed) Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 7/8] reset: make --mixed sparse-aware Victoria Dye via GitGitGadget
2021-11-29 15:52           ` [PATCH v6 8/8] unpack-trees: improve performance of next_cache_entry Victoria Dye via GitGitGadget
2021-11-29 18:37           ` [PATCH v6 0/8] Sparse Index: integrate with reset Elijah Newren
2021-11-29 19:44             ` Victoria Dye
2021-11-30  3:59               ` Elijah Newren
2021-12-01 20:26               ` Ævar Arnfjörð Bjarmason

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=52768318-ef8a-b26f-d4bc-d5c91779ccdb@github.com \
    --to=vdye@github.com \
    --cc=avarab@gmail.com \
    --cc=bagasdotme@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=gitgitgadget@gmail.com \
    --cc=gitster@pobox.com \
    --cc=me@ttaylorr.com \
    --cc=newren@gmail.com \
    --cc=phillip.wood@dunelm.org.uk \
    --cc=stolee@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).