From: Duy Nguyen <pclouds@gmail.com>
To: Elijah Newren <newren@gmail.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Junio C Hamano <gitster@pobox.com>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH v3] unpack_trees: fix breakage when o->src_index != o->dst_index
Date: Mon, 30 Apr 2018 18:29:06 +0200 [thread overview]
Message-ID: <CACsJy8CeDhrT9GXe9q5gqsAeq_sSQ8jyF2nMOFxzjwKtE31oPQ@mail.gmail.com> (raw)
In-Reply-To: <CABPp-BFsEPbTXq0cFE+gkXcXtP_1LOyQAUMMXBOdB16OJknDig@mail.gmail.com>
On Mon, Apr 30, 2018 at 6:19 PM, Elijah Newren <newren@gmail.com> wrote:
> Hi Duy,
>
> On Mon, Apr 30, 2018 at 7:45 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> On Mon, Apr 30, 2018 at 4:42 PM, Duy Nguyen <pclouds@gmail.com> wrote:
>>> On Sun, Apr 29, 2018 at 10:53 PM, Johannes Schindelin
>>> <Johannes.Schindelin@gmx.de> wrote:
>>>>> > @@ -1412,12 +1422,13 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
>>>>> > WRITE_TREE_SILENT |
>>>>> > WRITE_TREE_REPAIR);
>>>>> > }
>>>>> > - move_index_extensions(&o->result, o->dst_index);
>>>>> > + move_index_extensions(&o->result, o->src_index);
>>>>>
>>>>> While this looks like the right thing to do on paper, I believe it's
>>>>> actually broken for a specific case of untracked cache. In short,
>>>>> please do not touch this line. I will send a patch to revert
>>>>> edf3b90553 (unpack-trees: preserve index extensions - 2017-05-08),
>>>>> which essentially deletes this line, with proper explanation and
>>>>> perhaps a test if I could come up with one.
>>>>>
>>>>> When we update the index, we depend on the fact that all updates must
>>>>> invalidate the right untracked cache correctly. In this unpack
>>>>> operations, we start copying entries over from src to result. Since
>>>>> 'result' (at least from the beginning) does not have an untracked
>>>>> cache, it has nothing to invalidate when we copy entries over. By the
>>>>> time we have done preparing 'result', what's recorded in src's (or
>>>>> dst's for that matter) untracked cache may or may not apply to
>>>>> 'result' index anymore. This copying only leads to more problems when
>>>>> untracked cache is used.
>>>>
>>>> Is there really no way to invalidate just individual entries?
>>>
>>> Grr.... the short answer is the current code (i.e. without Elijah's
>>> changes) works but in a twisted way. So you get to keep untracked
>>> cache in the end.
>>
>> GAAAHH.. it works _with_ Elijah's changes (since he made the change
>> from dst to src) not without (and no performance regression).
>
> So...is that an Acked-by for the patch
Yes, Acked-by: me.
> or does the "two wrong make a
> right, I guess" comment suggest that we should still drop the
> move_index_extensions change (essentially reverting to v1 of the PATCH
> as found at 20180421193736.12722-1-newren@gmail.com), and you'll fix
> things up further in a separate series?
I think I'll stay away from this file for a while. When I gather
enough courage, I'll need to read it through since it sounds like a
mine field.
--
Duy
next prev parent reply other threads:[~2018-04-30 16:29 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-19 17:57 [PATCH v10 00/36] Add directory rename detection to git Elijah Newren
2018-04-19 17:57 ` [PATCH v10 01/36] directory rename detection: basic testcases Elijah Newren
2018-04-19 17:57 ` [PATCH v10 02/36] directory rename detection: directory splitting testcases Elijah Newren
2018-04-19 17:57 ` [PATCH v10 03/36] directory rename detection: testcases to avoid taking detection too far Elijah Newren
2018-04-19 17:57 ` [PATCH v10 04/36] directory rename detection: partially renamed directory testcase/discussion Elijah Newren
2018-04-19 17:57 ` [PATCH v10 05/36] directory rename detection: files/directories in the way of some renames Elijah Newren
2018-04-19 17:57 ` [PATCH v10 06/36] directory rename detection: testcases checking which side did the rename Elijah Newren
2018-04-19 17:57 ` [PATCH v10 07/36] directory rename detection: more involved edge/corner testcases Elijah Newren
2018-04-19 17:57 ` [PATCH v10 08/36] directory rename detection: testcases exploring possibly suboptimal merges Elijah Newren
2018-04-19 17:57 ` [PATCH v10 09/36] directory rename detection: miscellaneous testcases to complete coverage Elijah Newren
2018-04-19 17:57 ` [PATCH v10 10/36] directory rename detection: tests for handling overwriting untracked files Elijah Newren
2018-04-19 17:57 ` [PATCH v10 11/36] directory rename detection: tests for handling overwriting dirty files Elijah Newren
2018-04-19 17:57 ` [PATCH v10 12/36] merge-recursive: move the get_renames() function Elijah Newren
2018-04-19 17:58 ` [PATCH v10 13/36] merge-recursive: introduce new functions to handle rename logic Elijah Newren
2018-04-19 17:58 ` [PATCH v10 14/36] merge-recursive: fix leaks of allocated renames and diff_filepairs Elijah Newren
2018-04-19 17:58 ` [PATCH v10 15/36] merge-recursive: make !o->detect_rename codepath more obvious Elijah Newren
2018-04-19 17:58 ` [PATCH v10 16/36] merge-recursive: split out code for determining diff_filepairs Elijah Newren
2018-04-19 17:58 ` [PATCH v10 17/36] merge-recursive: make a helper function for cleanup for handle_renames Elijah Newren
2018-04-19 17:58 ` [PATCH v10 18/36] merge-recursive: add get_directory_renames() Elijah Newren
2018-05-06 23:41 ` SZEDER Gábor
2018-05-07 15:45 ` [PATCH] fixup! " Elijah Newren
2019-10-09 20:38 ` [PATCH v10 18/36] " Johannes Schindelin
2019-10-11 20:02 ` Elijah Newren
2019-10-12 19:23 ` Johannes Schindelin
2018-04-19 17:58 ` [PATCH v10 19/36] merge-recursive: check for directory level conflicts Elijah Newren
2018-04-19 17:58 ` [PATCH v10 20/36] merge-recursive: add computation of collisions due to dir rename & merging Elijah Newren
2018-04-19 17:58 ` [PATCH v10 21/36] merge-recursive: check for file level conflicts then get new name Elijah Newren
2018-04-19 17:58 ` [PATCH v10 22/36] merge-recursive: when comparing files, don't include trees Elijah Newren
2018-04-19 17:58 ` [PATCH v10 23/36] merge-recursive: apply necessary modifications for directory renames Elijah Newren
2018-04-19 17:58 ` [PATCH v10 24/36] merge-recursive: avoid clobbering untracked files with " Elijah Newren
2018-04-19 17:58 ` [PATCH v10 25/36] merge-recursive: fix overwriting dirty files involved in renames Elijah Newren
2018-04-19 20:48 ` Martin Ågren
2018-04-19 20:54 ` Martin Ågren
2018-04-19 21:06 ` Elijah Newren
2018-04-19 17:58 ` [PATCH v10 26/36] merge-recursive: fix remaining directory rename + dirty overwrite cases Elijah Newren
2018-04-19 17:58 ` [PATCH v10 27/36] directory rename detection: new testcases showcasing a pair of bugs Elijah Newren
2018-04-19 17:58 ` [PATCH v10 28/36] merge-recursive: avoid spurious rename/rename conflict from dir renames Elijah Newren
2018-04-19 17:58 ` [PATCH v10 29/36] merge-recursive: improve add_cacheinfo error handling Elijah Newren
2018-04-19 17:58 ` [PATCH v10 30/36] merge-recursive: move more is_dirty handling to merge_content Elijah Newren
2018-04-19 17:58 ` [PATCH v10 31/36] merge-recursive: avoid triggering add_cacheinfo error with dirty mod Elijah Newren
2018-04-19 17:58 ` [PATCH v10 32/36] t6046: testcases checking whether updates can be skipped in a merge Elijah Newren
2018-04-19 20:26 ` SZEDER Gábor
2018-04-19 20:55 ` Elijah Newren
2018-04-19 17:58 ` [PATCH v10 33/36] merge-recursive: fix was_tracked() to quit lying with some renamed paths Elijah Newren
2018-04-19 20:39 ` Martin Ågren
2018-04-19 20:54 ` Elijah Newren
2018-04-20 12:23 ` SZEDER Gábor
2018-04-20 15:23 ` Elijah Newren
2018-04-21 19:37 ` [RFC PATCH v10 32.5/36] unpack_trees: fix memory corruption with split_index when src != dst Elijah Newren
2018-04-21 20:13 ` Elijah Newren
2018-04-22 12:38 ` Duy Nguyen
2018-04-23 17:09 ` Elijah Newren
2018-04-23 17:37 ` Duy Nguyen
2018-04-23 18:05 ` Elijah Newren
2018-04-24 0:24 ` [PATCH v2] unpack_trees: fix breakage when o->src_index != o->dst_index Elijah Newren
2018-04-24 1:51 ` Junio C Hamano
2018-04-24 3:05 ` Junio C Hamano
2018-04-24 6:50 ` [PATCH v3] " Elijah Newren
2018-04-29 18:05 ` Duy Nguyen
2018-04-29 20:53 ` Johannes Schindelin
2018-04-30 14:42 ` Duy Nguyen
2018-04-30 14:45 ` Duy Nguyen
2018-04-30 16:19 ` Elijah Newren
2018-04-30 16:29 ` Duy Nguyen [this message]
2018-04-19 17:58 ` [PATCH v10 34/36] merge-recursive: fix remainder of was_dirty() to use original index Elijah Newren
2018-04-19 17:58 ` [PATCH v10 35/36] merge-recursive: make "Auto-merging" comment show for other merges Elijah Newren
2018-04-19 17:58 ` [PATCH v10 36/36] merge-recursive: fix check for skipability of working tree updates Elijah Newren
2018-04-19 18:35 ` [PATCH v10 00/36] Add directory rename detection to git Elijah Newren
2018-04-19 18:41 ` Stefan Beller
2018-04-19 19:54 ` Derrick Stolee
2018-04-19 20:22 ` Elijah Newren
2018-04-20 3:05 ` Junio C Hamano
2018-04-23 17:50 ` Elijah Newren
2018-04-24 20:20 ` [PATCH v10 1/2] fixup! merge-recursive: fix was_tracked() to quit lying with some renamed paths Elijah Newren
2018-04-24 20:21 ` [PATCH v10 2/2] fixup! t6046: testcases checking whether updates can be skipped in a merge Elijah Newren
2018-04-23 17:28 ` [PATCH v10 00/36] Add directory rename detection to git Elijah Newren
2018-04-23 23:46 ` Junio C Hamano
2018-04-24 0:15 ` Elijah Newren
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