From: Michael Haggerty <mhagger@alum.mit.edu>
To: Junio C Hamano <gitster@pobox.com>,
David Turner <dturner@twopensource.com>
Cc: 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: Fri, 29 Apr 2016 08:56:28 +0200 [thread overview]
Message-ID: <5723059C.5080406@alum.mit.edu> (raw)
In-Reply-To: <xmqqvb327nyz.fsf@gitster.mtv.corp.google.com>
On 04/27/2016 11:15 PM, Junio C Hamano wrote:
> Junio C Hamano <gitster@pobox.com> writes:
>
>> 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.
>
> ... but my understanding of the point of this patch may be flawed,
> in which case I of course am willing to be enlightened ;-)
I was thinking of this patch as documenting and enforcing a limitation
in the current implementation of pruning. But to be honest I can't think
of a reason that we would ever want to remove this limitation, so I am
OK with changing the policy to "REF_ISPRUNING always implies
REF_NODEREF" as you have suggested.
But I think it would be cleaner to achieve that goal with the following
change:
diff --git a/refs.c b/refs.c
index 5dc2473..1d4c12a 100644
--- a/refs.c
+++ b/refs.c
@@ -790,8 +790,10 @@ int ref_transaction_update(struct ref_transaction
*transaction,
if (transaction->state != REF_TRANSACTION_OPEN)
die("BUG: update called for transaction that is not open");
- if ((flags & REF_ISPRUNING) && !(flags & REF_NODEREF))
- die("BUG: REF_ISPRUNING set without REF_NODEREF");
+ if (flags & REF_ISPRUNING) {
+ /* Pruning is always non-recursive */
+ flags |= REF_NODEREF;
+ }
if (new_sha1 && !is_null_sha1(new_sha1) &&
check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 8fcbd7d..9faf17c 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2116,7 +2116,7 @@ static void prune_ref(struct ref_to_prune *r)
transaction = ref_transaction_begin(&err);
if (!transaction ||
ref_transaction_delete(transaction, r->name, r->sha1,
- REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
+ REF_ISPRUNING, NULL, &err) ||
ref_transaction_commit(transaction, &err)) {
ref_transaction_free(transaction);
error("%s", err.buf);
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 37a1a37..704eea7 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -15,7 +15,7 @@
/*
* Used as a flag in ref_update::flags when a loose ref is being
- * pruned.
+ * pruned. This flag implies REF_NODEREF.
*/
#define REF_ISPRUNING 0x04
Note that patch "add_update(): initialize the whole ref_update" should
then be adjusted to do the flag-tweak in the add_update() function.
If there are no objections, I will implement these changes in v2.
Michael
next prev parent reply other threads:[~2016-04-29 6:56 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
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 [this message]
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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