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From: Glen Choo <chooglen@google.com>
To: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org
Cc: Elijah Newren <newren@gmail.com>
Subject: Re: [PATCH 01/24] init-db: remove unnecessary global variable & document existing bug
Date: Thu, 11 May 2023 13:43:01 -0700	[thread overview]
Message-ID: <kl6lsfc2zjje.fsf@chooglen-macbookpro.roam.corp.google.com> (raw)
In-Reply-To: <12a251f77f679123d01892109694f8ee19b96252.1683431151.git.gitgitgadget@gmail.com>

"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:

> From: Elijah Newren <newren@gmail.com>
>
> This commit was prompted by a desire to move the functions which
> builtin/init-db.c and builtin/clone.c share out of the former file and
> into setup.c.  One issue that made it difficult was the
> init_is_bare_repository global variable.
>
> init_is_bare_repository is actually not very useful.  It merely stores
> the return value from is_bare_repository() and only for the duration of
> a few additional function calls before its value is checked, and none of
> those functions do anything that could change is_bare_repository()'s
> return value.  So, we can simply dispense with the global by replacing
> it with is_bare_repository().

I think the purpose of init_is_bare_repository is something different.
But based off my different understanding, I can't reproduce any
different behavior. I don't know if I'm just confused or not, but I'll
leave some breadcrumbs here to check my understanding.

Reordering the hunks for clarity,

> @@ -422,8 +436,6 @@ int init_db(const char *git_dir, const char *real_git_dir,
>  
>  	safe_create_dir(git_dir, 0);
>  
> -	init_is_bare_repository = is_bare_repository();
> -
>  	/* Check to see if the repository version is right.
>  	 * Note that a newly created repository does not have
>  	 * config file, so this will not fail.  What we are catching

Here, init_db() caches the value of is_bare_repository(), which itself
reads the value of is_bare_repository_cfg, which can be modified by when
we read "core.bare" via git_config(git_default_config) or similar
(basically, any config callback that uses git_default_config). It is
also modified in other places though, like setup.c.

IIUC, we haven't actually parsed "core.bare" at this point. The
git_config() call just above this calls "plaform_core_config", which is
either "mingw_core_config" (doesn't read "core.bare") or
noop_core_config (noop).

> @@ -231,9 +230,24 @@ static int create_default_files(const char *template_path,
>  	 * We must make sure command-line options continue to override any
>  	 * values we might have just re-read from the config.
>  	 */
> -	is_bare_repository_cfg = init_is_bare_repository || !work_tree;
>  	if (init_shared_repository != -1)
>  		set_shared_repository(init_shared_repository);
> +	/*
> +	 * TODO: heed core.bare from config file in templates if no
> +	 *       command-line override given
> +	 *
> +	 * Unfortunately, this location in the code is far too late to
> +	 * allow this to happen; both builtin/init.db and
> +	 * builtin/clone.c setup the new repository and call
> +	 * set_git_work_tree() before this point.  (Note that both do
> +	 * that repository setup before calling init_db(), which in
> +	 * turn calls create_default_files().)  Fixing it would
> +	 * require too much refactoring, and no one seems to have
> +	 * wanted this behavior in 15+ years, so we'll continue
> +	 * ignoring the config for now and just override
> +	 * is_bare_repository_cfg unconditionally.
> +	 */
> +	is_bare_repository_cfg = is_bare_repository() || !work_tree;
>  
>  	/*
>  	 * We would have created the above under user's umask -- under

Now, we're in the midst of the re-init. Expanding the context a little,
we see:

	git_config(git_default_config, NULL);

	/*
	 * We must make sure command-line options continue to override any
	 * values we might have just re-read from the config.
	 */
	is_bare_repository_cfg = init_is_bare_repository || !work_tree;

So now we've read the new config of the re-inited repo, which might have
"core.bare" set to a value other than what "git init-db [--bare]"
started with, so we want to _intentionally_ ignore it. We do this by
reading out the cached value, _not_ by calling is_bare_repository()
again. So it seems to me like this patch changes the intent.

Where I struggling with is how to make this behave badly. The lines
above seem to be defensive in nature - we never use
is_bare_repository_cfg past this point, but we want to guard against
unintentional behavior in the future.

But I thought that logging this value would show a difference in
behavior, e.g.

  diff --git a/builtin/init-db.c b/builtin/init-db.c
  index ba6e0b20fa..da3579d46d 100644
  --- a/builtin/init-db.c
  +++ b/builtin/init-db.c
  @@ -229,6 +229,8 @@ static int create_default_files(const char *template_path,
    * values we might have just re-read from the config.
    */
    is_bare_repository_cfg = init_is_bare_repository || !work_tree;
  +	printf_ln("is_bare_repository_cfg is %d", is_bare_repository_cfg);
  +
    if (init_shared_repository != -1)
      set_shared_repository(init_shared_repository);

  diff --git a/t/t1301-shared-repo.sh b/t/t1301-shared-repo.sh
  index 1b6437ec07..e4b978992e 100755
  --- a/t/t1301-shared-repo.sh
  +++ b/t/t1301-shared-repo.sh
  @@ -15,6 +15,14 @@ TEST_PASSES_SANITIZE_LEAK=true
  # Remove a default ACL from the test dir if possible.
  setfacl -k . 2>/dev/null

  +test_expect_success 're-init respects core.bare' '
  +	git init bare.git >actual &&
  +	grep "is_bare_repository_cfg is 0" actual &&
  +	git -C bare.git config core.bare true &&
  +	git init bare.git >actual &&
  +	grep "is_bare_repository_cfg is 1" actual
  +'
  +
  # User must have read permissions to the repo -> failure on --shared=0400
  test_expect_success 'shared = 0400 (faulty permission u-w)' '
    test_when_finished "rm -rf sub" &&

But apparently this doesn't work at all. I can't get this to print
"is_bare_repository_cfg is 1" no matter what I do, before or after your
patch. Maybe there's more at play here (e.g. with setup.c), but I
haven't figured that out.

If I'm right (which I'm not sure about), we might need to keep
init_is_bare_repository around _somewhere_. Not a global, but maybe
as a param.

  parent reply	other threads:[~2023-05-11 20:43 UTC|newest]

Thread overview: 115+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-07  3:45 [PATCH 00/24] Header cleanups (final splitting of cache.h, and some splitting of other headers) Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 01/24] init-db: remove unnecessary global variable & document existing bug Elijah Newren via GitGitGadget
2023-05-11 17:24   ` Calvin Wan
2023-05-12  1:55     ` Elijah Newren
2023-05-11 20:43   ` Glen Choo [this message]
2023-05-12  1:21     ` Elijah Newren
2023-05-12 17:26       ` Glen Choo
2023-05-07  3:45 ` [PATCH 02/24] init-db, clone: change unnecessary global into passed parameter Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 03/24] setup: adopt shared init-db & clone code Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 04/24] read-cache: move shared commit and ls-files code Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 05/24] add: modify add_files_to_cache() to avoid globals Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 06/24] read-cache: move shared add/checkout/commit code Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 07/24] statinfo: move stat_{data,validity} functions from cache/read-cache Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 08/24] run-command.h: move declarations for run-command.c from cache.h Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 09/24] name-hash.h: move declarations for name-hash.c " Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 10/24] sparse-index.h: move declarations for sparse-index.c " Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 11/24] preload-index.h: move declarations for preload-index.c from elsewhere Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 12/24] diff.h: move declaration for global in diff.c from cache.h Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 13/24] merge.h: move declarations for merge.c " Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 14/24] repository.h: move declaration of the_index " Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 15/24] read-cache*.h: move declarations for read-cache.c functions " Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 16/24] cache.h: remove this no-longer-used header Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 17/24] log-tree: replace include of revision.h with simple forward declaration Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 18/24] repository: remove unnecessary include of path.h Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 19/24] diff.h: remove unnecessary include of oidset.h Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 20/24] list-objects-filter-options.h: remove unneccessary include Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 21/24] builtin.h: remove unneccessary includes Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 22/24] git-compat-util.h: remove unneccessary include of wildmatch.h Elijah Newren via GitGitGadget
2023-05-07  3:45 ` [PATCH 23/24] hash-ll, hashmap: move oidhash() to hash-ll Elijah Newren via GitGitGadget
2023-05-11 17:24   ` Calvin Wan
2023-05-11 18:31     ` Jeff King
2023-05-11 18:39       ` Felipe Contreras
2023-05-12  2:08       ` Elijah Newren
2023-05-12  4:07         ` Jeff King
2023-05-07  3:45 ` [PATCH 24/24] fsmonitor-ll.h: split this header out of fsmonitor.h Elijah Newren via GitGitGadget
2023-05-08 15:29 ` [PATCH 00/24] Header cleanups (final splitting of cache.h, and some splitting of other headers) Junio C Hamano
2023-05-09  1:31   ` Elijah Newren
2023-05-09 16:03     ` Junio C Hamano
2023-05-08 15:55 ` Junio C Hamano
2023-05-11 17:41 ` Calvin Wan
2023-05-12  6:58   ` Elijah Newren
2023-05-12  7:04 ` [PATCH v2 00/27] " Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 01/27] init-db: document existing bug with core.bare in template config Elijah Newren via GitGitGadget
2023-05-12 21:34     ` Jonathan Tan
2023-05-16  3:08       ` Elijah Newren
2023-05-12  7:04   ` [PATCH v2 02/27] init-db: remove unnecessary global variable Elijah Newren via GitGitGadget
2023-05-12 20:20     ` Glen Choo
2023-05-12  7:04   ` [PATCH v2 03/27] init-db, clone: change unnecessary global into passed parameter Elijah Newren via GitGitGadget
2023-05-12 21:28     ` Jonathan Tan
2023-05-16  2:57       ` Elijah Newren
2023-05-12  7:04   ` [PATCH v2 04/27] setup: adopt shared init-db & clone code Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 05/27] read-cache: move shared commit and ls-files code Elijah Newren via GitGitGadget
2023-05-12 21:25     ` Jonathan Tan
2023-05-12  7:04   ` [PATCH v2 06/27] add: modify add_files_to_cache() to avoid globals Elijah Newren via GitGitGadget
2023-05-15 21:44     ` Jonathan Tan
2023-05-12  7:04   ` [PATCH v2 07/27] read-cache: move shared add/checkout/commit code Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 08/27] statinfo: move stat_{data,validity} functions from cache/read-cache Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 09/27] run-command.h: move declarations for run-command.c from cache.h Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 10/27] name-hash.h: move declarations for name-hash.c " Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 11/27] sparse-index.h: move declarations for sparse-index.c " Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 12/27] preload-index.h: move declarations for preload-index.c from elsewhere Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 13/27] diff.h: move declaration for global in diff.c from cache.h Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 14/27] merge.h: move declarations for merge.c " Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 15/27] repository.h: move declaration of the_index " Elijah Newren via GitGitGadget
2023-05-15 21:50     ` Jonathan Tan
2023-05-12  7:04   ` [PATCH v2 16/27] read-cache*.h: move declarations for read-cache.c functions " Elijah Newren via GitGitGadget
2023-05-16  0:00     ` Jonathan Tan
2023-05-12  7:04   ` [PATCH v2 17/27] cache.h: remove this no-longer-used header Elijah Newren via GitGitGadget
2023-05-16  0:02     ` Jonathan Tan
2023-05-16  3:02       ` Elijah Newren
2023-05-12  7:04   ` [PATCH v2 18/27] log-tree: replace include of revision.h with simple forward declaration Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 19/27] repository: remove unnecessary include of path.h Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 20/27] diff.h: remove unnecessary include of oidset.h Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 21/27] list-objects-filter-options.h: remove unneccessary include Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 22/27] builtin.h: remove unneccessary includes Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 23/27] git-compat-util.h: remove unneccessary include of wildmatch.h Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 24/27] merge-ll: rename from ll-merge Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 25/27] khash: name the structs that khash declares Elijah Newren via GitGitGadget
2023-05-12  7:04   ` [PATCH v2 26/27] hash-ll, hashmap: move oidhash() to hash-ll Elijah Newren via GitGitGadget
2023-05-16  0:16     ` Jonathan Tan
2023-05-16  3:06       ` Elijah Newren
2023-05-12  7:04   ` [PATCH v2 27/27] fsmonitor-ll.h: split this header out of fsmonitor.h Elijah Newren via GitGitGadget
2023-05-16  0:17     ` Jonathan Tan
2023-05-16  3:07       ` Elijah Newren
2023-05-16  6:33   ` [PATCH v3 00/28] Header cleanups (final splitting of cache.h, and some splitting of other headers) Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 01/28] init-db: document existing bug with core.bare in template config Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 02/28] init-db: remove unnecessary global variable Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 03/28] init-db, clone: change unnecessary global into passed parameter Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 04/28] setup: adopt shared init-db & clone code Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 05/28] read-cache: move shared commit and ls-files code Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 06/28] add: modify add_files_to_cache() to avoid globals Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 07/28] read-cache: move shared add/checkout/commit code Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 08/28] statinfo: move stat_{data,validity} functions from cache/read-cache Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 09/28] run-command.h: move declarations for run-command.c from cache.h Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 10/28] name-hash.h: move declarations for name-hash.c " Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 11/28] sparse-index.h: move declarations for sparse-index.c " Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 12/28] preload-index.h: move declarations for preload-index.c from elsewhere Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 13/28] diff.h: move declaration for global in diff.c from cache.h Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 14/28] merge.h: move declarations for merge.c " Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 15/28] repository.h: move declaration of the_index " Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 16/28] read-cache*.h: move declarations for read-cache.c functions " Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 17/28] cache.h: remove this no-longer-used header Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 18/28] log-tree: replace include of revision.h with simple forward declaration Elijah Newren via GitGitGadget
2023-05-16  6:33     ` [PATCH v3 19/28] repository: remove unnecessary include of path.h Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 20/28] diff.h: remove unnecessary include of oidset.h Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 21/28] list-objects-filter-options.h: remove unneccessary include Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 22/28] builtin.h: remove unneccessary includes Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 23/28] git-compat-util.h: remove unneccessary include of wildmatch.h Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 24/28] merge-ll: rename from ll-merge Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 25/28] khash: name the structs that khash declares Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 26/28] object-store-ll.h: split this header out of object-store.h Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 27/28] hash-ll, hashmap: move oidhash() to hash-ll Elijah Newren via GitGitGadget
2023-05-16  6:34     ` [PATCH v3 28/28] fsmonitor-ll.h: split this header out of fsmonitor.h Elijah Newren via GitGitGadget
2023-05-23 19:49     ` [PATCH v3 00/28] Header cleanups (final splitting of cache.h, and some splitting of other headers) Calvin Wan
2023-05-24  0:11       ` Elijah Newren

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