git.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Derrick Stolee <derrickstolee@github.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
	Victoria Dye <vdye@github.com>,
	Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH v2 5/6] cache API: add a "INDEX_STATE_INIT" macro/function, add release_index()
Date: Thu, 12 Jan 2023 17:19:20 +0100	[thread overview]
Message-ID: <230112.86zganzpwk.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <270ef93c-cfdc-d119-5740-f704d7f2a029@github.com>


On Thu, Jan 12 2023, Derrick Stolee wrote:

> On 1/12/2023 7:55 AM, Ævar Arnfjörð Bjarmason wrote:
>> As we'll see in a subsequent commit we'll get advantages from always
>> initializing the "repo" member of the "struct index_state". To make
>> that easier let's introduce an initialization macro & function.
>> 
>> The various ad-hoc initialization of the structure can then be changed
>> over to it, and we can remove the various "0" assignments in
>> discard_index() in favor of calling index_state_init() at the end.
>
>> -	memset(&o->result, 0, sizeof(o->result));
>> +	index_state_init(&o->result);
>>  	o->result.initialized = 1;
>
> It's interesting that 'struct index_state' has an 'initialized'
> member that we aren't setting in index_state_init(). Perhaps it's
> only being used in special cases like this, and means something
> more specific than "index_state_init() was run"? Or maybe we
> could add it to INDEX_STATE_INIT and drop this line?

It's unrelated, and doing that would be a bug. It's a bit unfortunately
named, a better name might be "read_index_data" or something.

It was added in 913e0e99b6a (unpack_trees(): protect the handcrafted
in-core index from read_cache(), 2008-08-23), which shows the use-case,
i.e. it's for avoiding re-reading the index file itself (or in that
case, to trust our hand-crafted faked-up version of it).

I opted not to mention it in the commit message, after being
sufficiently convinced that it was unrelated, which was probably a
mistake :)

Just as a sanity check, we do have really good test coverage of the
difference, at least 1/2 of the tests I bothered to wait for failed when
I tried this on top:

diff --git a/cache.h b/cache.h
index 4bf14e0bd94..1f8e5f4e823 100644
--- a/cache.h
+++ b/cache.h
@@ -371,6 +371,7 @@ struct index_state {
  * "r" argument to index_state_init() in that case.
  */
 #define INDEX_STATE_INIT(r) { \
+	.initialized = 1, \
 	.repo = (r), \
 }
 void index_state_init(struct index_state *istate, struct repository *r);

  reply	other threads:[~2023-01-12 16:23 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-10  6:17 [PATCH 0/5] cache API: always have a "istate->repo" Ævar Arnfjörð Bjarmason
2023-01-10  6:17 ` [PATCH 1/5] builtin/difftool.c: { 0 }-initialize rather than using memset() Ævar Arnfjörð Bjarmason
2023-01-10  6:17 ` [PATCH 2/5] sparse-index.c: expand_to_path() can assume non-NULL "istate" Ævar Arnfjörð Bjarmason
2023-01-10  6:17 ` [PATCH 3/5] sparse-index API: fix TODO, BUG() out on NULL ensure_full_index() Ævar Arnfjörð Bjarmason
2023-01-10 10:35   ` Philip Oakley
2023-01-10 12:22     ` Ævar Arnfjörð Bjarmason
2023-01-10 14:58   ` Derrick Stolee
2023-01-10  6:17 ` [PATCH 4/5] read-cache.c: refactor set_new_index_sparsity() for subsequent commit Ævar Arnfjörð Bjarmason
2023-01-10  6:17 ` [PATCH 5/5] treewide: always have a valid "index_state.repo" member Ævar Arnfjörð Bjarmason
2023-01-10 12:24   ` Ævar Arnfjörð Bjarmason
2023-01-10 13:13   ` Jeff Hostetler
2023-01-10 15:08   ` Derrick Stolee
2023-01-10 15:09 ` [PATCH 0/5] cache API: always have a "istate->repo" Derrick Stolee
2023-01-12 12:55 ` [PATCH v2 0/6] " Ævar Arnfjörð Bjarmason
2023-01-12 12:55   ` [PATCH v2 1/6] builtin/difftool.c: { 0 }-initialize rather than using memset() Ævar Arnfjörð Bjarmason
2023-01-12 12:55   ` [PATCH v2 2/6] sparse-index.c: expand_to_path() can assume non-NULL "istate" Ævar Arnfjörð Bjarmason
2023-01-12 12:55   ` [PATCH v2 3/6] sparse-index API: BUG() out on NULL ensure_full_index() Ævar Arnfjörð Bjarmason
2023-01-12 12:55   ` [PATCH v2 4/6] read-cache.c: refactor set_new_index_sparsity() for subsequent commit Ævar Arnfjörð Bjarmason
2023-01-12 12:55   ` [PATCH v2 5/6] cache API: add a "INDEX_STATE_INIT" macro/function, add release_index() Ævar Arnfjörð Bjarmason
2023-01-12 15:21     ` Derrick Stolee
2023-01-12 16:19       ` Ævar Arnfjörð Bjarmason [this message]
2023-01-12 16:47         ` Derrick Stolee
2023-01-12 12:55   ` [PATCH v2 6/6] treewide: always have a valid "index_state.repo" member Ævar Arnfjörð Bjarmason
2023-01-12 15:22     ` Derrick Stolee
2023-01-12 15:23   ` [PATCH v2 0/6] cache API: always have a "istate->repo" Derrick Stolee
2023-01-13 18:29     ` Junio C Hamano
2023-01-13 19:22   ` Junio C Hamano
2023-01-16 13:38     ` Ævar Arnfjörð Bjarmason
2023-01-16 16:53       ` Philip Oakley
2023-01-16 18:39         ` Junio C Hamano
2023-01-17 13:57           ` [PATCH] treewide: always have a valid "index_state.repo" member Ævar Arnfjörð Bjarmason
2023-01-17 15:34             ` Derrick Stolee

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

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

  git send-email \
    --in-reply-to=230112.86zganzpwk.gmgdl@evledraar.gmail.com \
    --to=avarab@gmail.com \
    --cc=derrickstolee@github.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=jeffhost@microsoft.com \
    --cc=vdye@github.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.
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 NNTP newsgroup(s).