From: Junio C Hamano <gitster@pobox.com>
To: David Turner <dturner@twopensource.com>
Cc: "Michael Haggerty" <mhagger@alum.mit.edu>,
git@vger.kernel.org, "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Jeff King" <peff@peff.net>,
"Ramsay Jones" <ramsay@ramsayjones.plus.com>
Subject: Re: [PATCH 15/29] ref_transaction_create(): disallow recursive pruning
Date: Wed, 27 Apr 2016 13:45:07 -0700 [thread overview]
Message-ID: <xmqqh9em93xo.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <1461788637.11504.3.camel@twopensource.com> (David Turner's message of "Wed, 27 Apr 2016 16:23:57 -0400")
David Turner <dturner@twopensource.com> writes:
> On Wed, 2016-04-27 at 11:47 -0700, Junio C Hamano wrote:
>> Michael Haggerty <mhagger@alum.mit.edu> writes:
>>
>> > It is nonsensical (and a little bit dangerous) to use REF_ISPRUNING
>> > without REF_NODEREF. Forbid it explicitly. Change the one
>> > REF_ISPRUNING
>> > caller to pass REF_NODEREF too.
>> >
>> > Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
>> > ---
>> > This also makes later patches a bit clearer.
>>
>> I wonder if it is more future-proof to solve this by doing
>>
>> -#define REF_ISPRUNING 0x04
>> +#define REF_ISPRUNING (0x04 | REF_NODEREF)
>>
>> instead. It makes the intention clear that pruning is always about
>> the single level (i.e. no-deref).
>
> I think the approach in Michael's patch might be clearer than yours,
> since someone reading the code doesn't have to look at the definition
> of REF_ISPRUNING to understand what is going on.
I have to strongly disagree, assuming that my understanding of the
point of this patch correctly.
If a casual reader sees this code:
ref_transaction_delete(transaction, r->name, r->sha1,
REF_ISPRUNING | REF_NODEREF, NULL, &err)
it gives an incorrect impression that there may also be a valid case
to make a "delete" call with ISPRUNING alone without NODEREF, in
other codepaths and under certain conditions, and write an incorrect
ref_transaction_delete(transaction, refname, sha1,
REF_ISPRUNING, NULL, &err)
in her new code. Or a careless programmer and reviewer may not even
memorize and remember what the new world order is when they see such
a code and let it pass.
As I understand that we declare that "to prune a ref from set of
loose refs is to prune the named one, never following a symbolic
ref" is the new world order with this patch, making sure that
ISPRUNING automatically and always mean NODEREF will eliminate the
possibility that any new code makes an incorrect call to "delete",
which I think is much better.
next prev parent reply other threads:[~2016-04-27 20:45 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-27 16:57 [PATCH 00/29] Yet more preparation for reference backends Michael Haggerty
2016-04-27 16:57 ` [PATCH 01/29] safe_create_leading_directories(): improve docstring Michael Haggerty
2016-04-27 16:57 ` [PATCH 02/29] remove_dir_recursively(): add docstring Michael Haggerty
2016-04-27 16:57 ` [PATCH 03/29] refname_is_safe(): use skip_prefix() Michael Haggerty
2016-04-27 16:57 ` [PATCH 04/29] refname_is_safe(): don't allow the empty string Michael Haggerty
2016-04-27 16:57 ` [PATCH 05/29] refname_is_safe(): insist that the refname already be normalized Michael Haggerty
2016-04-27 17:59 ` Junio C Hamano
2016-04-27 20:10 ` David Turner
2016-04-27 20:15 ` Jeff King
2016-04-27 20:34 ` David Turner
2016-04-27 20:37 ` Jeff King
2016-04-27 22:19 ` Jeff King
2016-04-28 17:44 ` David Turner
2016-04-27 16:57 ` [PATCH 06/29] commit_ref_update(): write error message to *err, not stderr Michael Haggerty
2016-04-27 16:57 ` [PATCH 07/29] rename_ref(): remove unneeded local variable Michael Haggerty
2016-04-27 16:57 ` [PATCH 08/29] ref_transaction_commit(): remove local variable n Michael Haggerty
2016-04-27 18:16 ` Junio C Hamano
2016-04-27 20:45 ` Junio C Hamano
2016-04-27 16:57 ` [PATCH 09/29] read_raw_ref(): rename flags argument to type Michael Haggerty
2016-04-27 16:57 ` [PATCH 10/29] read_raw_ref(): clear *type at start of function Michael Haggerty
2016-04-27 16:57 ` [PATCH 11/29] read_raw_ref(): rename symref argument to referent Michael Haggerty
2016-04-27 16:57 ` [PATCH 12/29] read_raw_ref(): improve docstring Michael Haggerty
2016-04-27 18:31 ` Junio C Hamano
2016-04-27 16:57 ` [PATCH 13/29] lock_ref_sha1_basic(): remove unneeded local variable Michael Haggerty
2016-04-27 16:57 ` [PATCH 14/29] refs: make error messages more consistent Michael Haggerty
2016-04-27 16:57 ` [PATCH 15/29] ref_transaction_create(): disallow recursive pruning Michael Haggerty
2016-04-27 18:47 ` Junio C Hamano
2016-04-27 20:23 ` David Turner
2016-04-27 20:45 ` Junio C Hamano [this message]
2016-04-27 21:15 ` Junio C Hamano
2016-04-28 17:48 ` David Turner
2016-04-28 20:15 ` Junio C Hamano
2016-04-29 6:56 ` Michael Haggerty
2016-04-29 8:19 ` Junio C Hamano
2016-04-29 8:41 ` Junio C Hamano
2016-04-29 14:29 ` Michael Haggerty
2016-04-27 16:57 ` [PATCH 16/29] ref_transaction_commit(): correctly report close_ref() failure Michael Haggerty
2016-04-27 16:57 ` [PATCH 17/29] delete_branches(): use resolve_refdup() Michael Haggerty
2016-04-27 16:57 ` [PATCH 18/29] refs: allow log-only updates Michael Haggerty
2016-04-27 16:57 ` [PATCH 19/29] refs: don't dereference on rename Michael Haggerty
2016-04-27 18:55 ` Junio C Hamano
2016-04-29 7:38 ` Michael Haggerty
2016-04-29 8:53 ` Junio C Hamano
2016-04-29 10:57 ` Michael Haggerty
2016-04-29 12:12 ` Jeff King
2016-04-29 13:55 ` Michael Haggerty
2016-04-29 14:08 ` Jeff King
2016-04-29 15:29 ` Junio C Hamano
2016-04-29 23:21 ` David Turner
2016-04-30 3:48 ` Michael Haggerty
2016-05-02 17:55 ` Junio C Hamano
2016-04-27 16:57 ` [PATCH 20/29] verify_refname_available(): adjust constness in declaration Michael Haggerty
2016-04-27 16:57 ` [PATCH 21/29] add_update(): initialize the whole ref_update Michael Haggerty
2016-04-27 16:57 ` [PATCH 22/29] lock_ref_for_update(): new function Michael Haggerty
2016-04-27 16:57 ` [PATCH 23/29] unlock_ref(): move definition higher in the file Michael Haggerty
2016-04-27 16:57 ` [PATCH 24/29] ref_transaction_update(): check refname_is_safe() at a minimum Michael Haggerty
2016-04-27 20:14 ` Junio C Hamano
2016-04-29 7:42 ` Michael Haggerty
2016-04-29 8:53 ` Junio C Hamano
2016-04-27 16:57 ` [PATCH 25/29] refs: resolve symbolic refs first Michael Haggerty
2016-04-28 23:40 ` David Turner
2016-04-29 9:51 ` Michael Haggerty
2016-04-29 23:14 ` David Turner
2016-05-02 18:06 ` Junio C Hamano
2016-04-27 16:57 ` [PATCH 26/29] lock_ref_for_update(): don't re-read non-symbolic references Michael Haggerty
2016-04-27 16:57 ` [PATCH 27/29] lock_ref_for_update(): don't resolve symrefs Michael Haggerty
2016-04-27 16:57 ` [PATCH 28/29] commit_ref_update(): remove the flags parameter Michael Haggerty
2016-04-27 16:57 ` [PATCH 29/29] lock_ref_sha1_basic(): only handle REF_NODEREF mode Michael Haggerty
2016-04-29 15:43 ` Junio C Hamano
2016-04-29 1:14 ` [PATCH 00/29] Yet more preparation for reference backends David Turner
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