From: Glen Choo <chooglen@google.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Glen Choo via GitGitGadget" <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, Jonathan Tan <jonathantanmy@google.com>,
Emily Shaffer <nasamuffin@google.com>
Subject: Re: [PATCH 10/14] (RFC-only) config: finish config_fn_t refactor
Date: Mon, 08 May 2023 14:00:51 -0700 [thread overview]
Message-ID: <kl6lr0rq1qt8.fsf@chooglen-macbookpro.roam.corp.google.com> (raw)
In-Reply-To: <230501.868re8jna4.gmgdl@evledraar.gmail.com>
Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
> On Fri, Apr 21 2023, Glen Choo via GitGitGadget wrote:
>
>> From: Glen Choo <chooglen@google.com>
>
> I like the general goal of this series, i.e. to get rid of the "reader"
> callback, and pass stuff more explicitly.
>
> But as I pointed out in
> https://lore.kernel.org/git/RFC-cover-0.5-00000000000-20230317T042408Z-avarab@gmail.com/
> I think this part (and the preceding two commits) are really taking is
> down the wrong path.
>
> To demonstrate why, here's a patch-on-top of this topic as a whole where
> I renamed the "kvi" struct members. I've excluded config.c itself (as
> its internals aren't interesting for the purposes of this discussion):
>
> [Patch showing used kvi members...]
>
> So, as this shows us your 08/14 has gone through the effort of passing
> this "kvi" info to every single callback, but it's only this handful
> that actually needs this information.
The attached patch misses the majority of "kvi" users, which use it in
die_bad_number(). This change happens in Patch 13/14, where the whole
"kvi" is passed into config.c machinery. It's still a much smaller
number of config callbacks than the ones changed in these few patches,
but it's more than a handful, I'd think.
> So, even if we *can* get this to work I don't think it's worth it,
> especially as this would preclude giving these config callbacks some
> "lighter" API that doesn't take the trouble of recording and ferrying
> this information to them.
I assume the "lighter API" refers to the current API?
If I'm reading this correctly, your concern isn't primarily about
reducing churn, it's YAGNI - since most callers don't need this info,
they should be able to reap the benefits of an API that doesn't provide
that info. Thus, you're proposing to having both the current API and a
new kvi-based one?
If so, I don't think that's a good route to take:
- Having both *_kvi() and "old" variants will add bloat to an already
bloated config API. Even without further changes, we'd need to add
*_kvi() to at least config_with_options() and repo_config(), as well
as all of the functions that config_with_options() uses under the
hood (some of which are public).
To some extent, this can be managed by shrinking the config API (e.g.
like your suggestion to get rid of git_config_from_file() [1]), but
IMO that needs more discussion.
- What benefit is the old API giving us vs the new one? It won't be any
faster since the machinery will need to support the new API, and even
if it were, the benefit would be tiny. In some cases it might be nice
to use the config callback in a non-config setting, but this patch
shows that those are rare and can be easily worked around.
- I strongly suspect that we'd already like "kvi" in more places, and if
we made it readily available, we would add these additional callers.
E.g. we already use it to give additional diagnostics when failing to
parse a number, and there's no reason why we shouldn't do this when
doing other kinds of parsing (e.g. date in git_config_expiry_date() or
color in color_parse_mem()).
If your concern really is primarily about churn and we actually want to
move everything to the new API eventually, wouldn't it be better to bite
the bullet and take a one time, well-scoped churn cost instead of a
longer migration?
[1] https://lore.kernel.org/git/230307.86wn3szrzu.gmgdl@evledraar.gmail.com/
> I think this should also neatly answer some of your outstanding
> questions. Especially as the above shows that the only non-test caller
> that needs "linenr" is the builtin/config.c caller that my proposed RFC
> (linked above) tackled directly. Most of these callbacks just need the
> more basic "scope".
I didn't see where builtin/config.c was handled in the above link.
Perhaps you meant a different RFC,
https://github.com/avar/git/commit/0233297a359bbda43a902dd0213aacdca82faa34?
> So, in particular:
>
>> Here's an exhaustive list of all of the changes:
>>
>> * Cases that need a judgement call
>>
>> - trace2/tr2_cfg.c:tr2_cfg_set_fl()
>>
>> This function needs to account for tr2_cfg_cb() now using "kvi".
>> Since this is only called (indirectly) by git_config_set(), config
>> source information has never been available here, so just pass NULL.
>> It will be tr2_cfg_cb()'s responsibility to not use "kvi".
>
> Just adding a "CONFIG_SCOPE_IN_PROCESS", "CONFIG_SCOPE_SET" or whatever
> you'd want to call it seems to make much more sense here, no?
CONFIG_SCOPE_SET makes sense.
>> - builtin/checkout.c:checkout_main()
>>
>> This calls git_xmerge_config() as a shorthand for parsing a CLI arg.
>> "kvi" doesn't apply, so just pass NULL. This might be worth
>> refactoring away, since git_xmerge_config() can call
>> git_default_config().
>
> Another example of a caller which never actually cares about this data,
> so if it doesn't need to have it passed to it, it doesn't need to fake
> it up either.
Here's a case of YAGNI I mentioned above and I agree it would be nice to
not have to fake a "kvi". However, git_xmerge_config() can call
git_defualt_config() so this seems more like it's abusing the config
callback to parse a CLI arg. A better resolution would be to have a
function dedicated to parsing "merge.conflictstyle".
>> * Hard for cocci to catch
>>
>> - urlmatch.c
>>
>> Manually refactor the custom config callbacks in "struct
>> urlmatch_config".
>>
>> - diff.h, fsck.h, grep.h, ident.h, xdiff-interface.h
>>
>> "struct key_value_info" hasn't been defined yet, so forward declare
>> it. Alternatively, maybe these files should "#include config.h".
>
> All of these problems go away if you don't insist on changing every
> single caller, you'll just have a step where you remove the current
> global in favor of some "config callback with kvi" info, and "make" will
> spot those callers that aren't converted yet.
>
> Those changes will be trivial enough (just the callers I noted above) to
> not require the tricky cocci patch in 08/14.
>
>> * Likely deficiencies in .cocci patch
>>
>> - submodule-config.c:gitmodules_cb()
>>
>> Manually refactor a parse_config() call that gets missed because it
>> uses a different "*data" arg.
>>
>> - grep.h, various
>>
>> Manually refactor grep_config() calls. Not sure why these don't get
>> picked up.
>>
>> - config.c:git_config_include(), http.c:http_options()
>>
>> Manually add "kvi" where it was missed. Not sure why they get missed.
>>
>> - builtin/clone.c:write_one_config()
>>
>> Manually refactor a git_clone_config() call. Probably got missed
>> because I didn't include git_config_parse_parameter().
>>
>> - ident.h
>>
>> Remove the UNUSED attribute. Not sure why this is the only instance
>> of this.
>>
>> - git-compat-util.h, compat/mingw.[h|c]
>>
>> Manually refactor noop_core_config(), platform_core_config() and
>> mingw_core_config(). I can probably add these as "manual fixups" in
>> cocci.
>
> ditto.
Yeah, there was definitely more cocci trickery than I'd like. Btw, if
you comments on the .cocci file itself, feel free to share. I obviously
just hacked together something based on a very rudimentary understanding
of cocci and I'd love suggestions on how to improve.
next prev parent reply other threads:[~2023-05-08 21:01 UTC|newest]
Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 19:13 [PATCH 00/14] [RFC] config: remove global state from config iteration Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 01/14] config.c: introduce kvi_fn(), use it for configsets Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 02/14] config.c: use kvi for CLI config Glen Choo via GitGitGadget
2023-05-01 11:06 ` Ævar Arnfjörð Bjarmason
2023-04-21 19:13 ` [PATCH 03/14] config: use kvi for config files Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 04/14] config: add kvi.path, use it to evaluate includes Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 05/14] config: pass source to config_parser_event_fn_t Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 06/14] config: inline git_color_default_config Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 07/14] urlmatch.h: use config_fn_t type Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 08/14] (RFC-only) config: add kvi arg to config_fn_t Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 09/14] (RFC-only) config: apply cocci to config_fn_t implementations Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 10/14] (RFC-only) config: finish config_fn_t refactor Glen Choo via GitGitGadget
2023-05-01 11:19 ` Ævar Arnfjörð Bjarmason
2023-05-05 21:07 ` Jonathan Tan
2023-05-09 22:46 ` Glen Choo
2023-05-11 16:21 ` Jonathan Tan
2023-05-08 21:00 ` Glen Choo [this message]
2023-04-21 19:13 ` [PATCH 11/14] config: remove current_config_(line|name|origin_type) Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 12/14] config: remove current_config_scope() Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 13/14] config: pass kvi to die_bad_number() Glen Choo via GitGitGadget
2023-04-21 19:13 ` [PATCH 14/14] config: remove config_reader from configset_add_value Glen Choo via GitGitGadget
2023-05-30 18:41 ` [PATCH v2 00/14] [RFC] config: remove global state from config iteration Glen Choo via GitGitGadget
2023-05-30 18:41 ` [PATCH v2 01/14] config: inline git_color_default_config Glen Choo via GitGitGadget
2023-05-30 18:42 ` [PATCH v2 02/14] urlmatch.h: use config_fn_t type Glen Choo via GitGitGadget
2023-05-30 18:42 ` [PATCH v2 03/14] (RFC-only) config: add kvi arg to config_fn_t Glen Choo via GitGitGadget
2023-06-01 9:50 ` Phillip Wood
2023-06-01 16:22 ` Glen Choo
2023-06-02 9:54 ` Phillip Wood
2023-06-02 16:46 ` Glen Choo
2023-06-05 9:38 ` Phillip Wood
2023-06-09 23:19 ` Glen Choo
2023-05-30 18:42 ` [PATCH v2 04/14] (RFC-only) config: apply cocci to config_fn_t implementations Glen Choo via GitGitGadget
2023-05-30 18:42 ` [PATCH v2 05/14] (RFC-only) config: finish config_fn_t refactor Glen Choo via GitGitGadget
2023-06-01 22:17 ` Jonathan Tan
2023-05-30 18:42 ` [PATCH v2 06/14] config.c: pass kvi in configsets Glen Choo via GitGitGadget
2023-06-01 22:21 ` Jonathan Tan
2023-05-30 18:42 ` [PATCH v2 07/14] config: provide kvi with config files Glen Choo via GitGitGadget
2023-06-01 22:41 ` Jonathan Tan
2023-06-01 23:54 ` Jonathan Tan
2023-05-30 18:42 ` [PATCH v2 08/14] builtin/config.c: test misuse of format_config() Glen Choo via GitGitGadget
2023-05-30 18:42 ` [PATCH v2 09/14] config.c: provide kvi with CLI config Glen Choo via GitGitGadget
2023-06-01 23:35 ` Jonathan Tan
2023-06-02 17:26 ` Glen Choo
2023-05-30 18:42 ` [PATCH v2 10/14] trace2: plumb config kvi Glen Choo via GitGitGadget
2023-06-01 23:38 ` Jonathan Tan
2023-05-30 18:42 ` [PATCH v2 11/14] config: pass kvi to die_bad_number() Glen Choo via GitGitGadget
2023-06-01 23:48 ` Jonathan Tan
2023-06-02 17:23 ` Glen Choo
2023-05-30 18:42 ` [PATCH v2 12/14] config.c: remove config_reader from configsets Glen Choo via GitGitGadget
2023-05-30 18:42 ` [PATCH v2 13/14] config: add kvi.path, use it to evaluate includes Glen Choo via GitGitGadget
2023-06-02 0:06 ` Jonathan Tan
2023-05-30 18:42 ` [PATCH v2 14/14] config: pass source to config_parser_event_fn_t Glen Choo via GitGitGadget
2023-06-02 0:08 ` Jonathan Tan
2023-06-02 17:20 ` Glen Choo
2023-06-20 19:43 ` [PATCH v3 00/12] config: remove global state from config iteration Glen Choo via GitGitGadget
2023-06-20 19:43 ` [PATCH v3 01/12] config: inline git_color_default_config Glen Choo via GitGitGadget
2023-06-20 21:01 ` Junio C Hamano
2023-06-20 19:43 ` [PATCH v3 02/12] urlmatch.h: use config_fn_t type Glen Choo via GitGitGadget
2023-06-20 21:02 ` Junio C Hamano
2023-06-20 19:43 ` [PATCH v3 03/12] config: add ctx arg to config_fn_t Glen Choo via GitGitGadget
2023-06-20 19:43 ` [PATCH v3 04/12] config.c: pass ctx in configsets Glen Choo via GitGitGadget
2023-06-20 21:19 ` Junio C Hamano
2023-06-20 19:43 ` [PATCH v3 05/12] config: pass ctx with config files Glen Choo via GitGitGadget
2023-06-20 19:43 ` [PATCH v3 06/12] builtin/config.c: test misuse of format_config() Glen Choo via GitGitGadget
2023-06-20 21:35 ` Junio C Hamano
2023-06-20 23:06 ` Glen Choo
2023-06-23 20:32 ` Jonathan Tan
2023-06-24 1:31 ` Jeff King
2023-06-28 17:28 ` Glen Choo
2023-06-20 19:43 ` [PATCH v3 07/12] config.c: pass ctx with CLI config Glen Choo via GitGitGadget
2023-06-23 20:35 ` Jonathan Tan
2023-06-23 21:41 ` Glen Choo
2023-06-20 19:43 ` [PATCH v3 08/12] trace2: plumb config kvi Glen Choo via GitGitGadget
2023-06-23 20:40 ` Jonathan Tan
2023-06-20 19:43 ` [PATCH v3 09/12] config: pass kvi to die_bad_number() Glen Choo via GitGitGadget
2023-06-20 19:43 ` [PATCH v3 10/12] config.c: remove config_reader from configsets Glen Choo via GitGitGadget
2023-06-23 20:57 ` Jonathan Tan
2023-06-23 21:33 ` Junio C Hamano
2023-06-20 19:43 ` [PATCH v3 11/12] config: add kvi.path, use it to evaluate includes Glen Choo via GitGitGadget
2023-06-20 19:43 ` [PATCH v3 12/12] config: pass source to config_parser_event_fn_t Glen Choo via GitGitGadget
2023-06-20 21:46 ` Junio C Hamano
2023-06-21 21:46 ` [PATCH v3 00/12] config: remove global state from config iteration Junio C Hamano
2023-06-21 23:06 ` Glen Choo
2023-06-23 21:02 ` Jonathan Tan
2023-06-23 21:33 ` Junio C Hamano
2023-06-23 21:45 ` Glen Choo
2023-06-26 18:11 ` [PATCH v4 " Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 01/12] config: inline git_color_default_config Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 02/12] urlmatch.h: use config_fn_t type Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 03/12] config: add ctx arg to config_fn_t Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 04/12] config.c: pass ctx in configsets Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 05/12] config: pass ctx with config files Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 06/12] builtin/config.c: test misuse of format_config() Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 07/12] config.c: pass ctx with CLI config Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 08/12] trace2: plumb config kvi Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 09/12] config: pass kvi to die_bad_number() Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 10/12] config.c: remove config_reader from configsets Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 11/12] config: add kvi.path, use it to evaluate includes Glen Choo via GitGitGadget
2023-06-26 18:11 ` [PATCH v4 12/12] config: pass source to config_parser_event_fn_t Glen Choo via GitGitGadget
2023-06-26 20:45 ` [PATCH v4 00/12] config: remove global state from config iteration Junio C Hamano
2023-06-28 19:26 ` [PATCH v5 00/11] " Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 01/11] config: inline git_color_default_config Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 02/11] urlmatch.h: use config_fn_t type Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 03/11] config: add ctx arg to config_fn_t Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 04/11] config.c: pass ctx in configsets Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 05/11] config: pass ctx with config files Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 06/11] config.c: pass ctx with CLI config Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 07/11] trace2: plumb config kvi Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 08/11] config: pass kvi to die_bad_number() Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 09/11] config.c: remove config_reader from configsets Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 10/11] config: add kvi.path, use it to evaluate includes Glen Choo via GitGitGadget
2023-06-28 19:26 ` [PATCH v5 11/11] config: pass source to config_parser_event_fn_t Glen Choo via GitGitGadget
2023-06-28 22:23 ` [PATCH v5 00/11] config: remove global state from config iteration Jonathan Tan
2023-06-28 22:47 ` Junio C Hamano
2023-07-11 18:41 ` Phillip Wood
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