From: "René Scharfe" <l.s.r@web.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Git List" <git@vger.kernel.org>,
"SZEDER Gábor" <szeder.dev@gmail.com>,
"Martin Koegler" <martin.koegler@chello.at>
Subject: Re: [PATCH] fsck: check results of lookup_blob() and lookup_tree() for NULL
Date: Thu, 5 Oct 2017 21:41:10 +0200 [thread overview]
Message-ID: <1cf044ae-ae3f-4d44-3aac-b5cc6584de1e@web.de> (raw)
In-Reply-To: <xmqqh8vfftp7.fsf@gitster.mtv.corp.google.com>
Am 04.10.2017 um 06:00 schrieb Junio C Hamano:
> René Scharfe <l.s.r@web.de> writes:
>> lookup_blob() and lookup_tree() can return NULL if they find an object
>> of an unexpected type. Error out of fsck_walk_tree() in that case, like
>> we do when encountering a bad file mode. An error message is already
>> shown by object_as_type(), which gets called by the lookup functions.
>
> The result from options->walk() is checked, and among the callbacks
> that are assigned to the .walk field:
>
> - mark_object() in builtin/fsck.c gives its own error message to diagnose broken link
> and returns 1;
>
> - mark_used() in builtin/fsck.c silently returns 1;
>
> - mark_link() in builtin/index-pack.c does the same; and
>
> - check_object() in builtin/unpack-objects.c does the same,
>
> when they see a NULL object.
>
> This patch may avoid the "unexpected behaviour" coming from
> expecting that &((struct tree *)NULL)->object == NULL the current
> code does, but it also changes the behaviour. The loop used to
> diagnose a fishy entry in the tree we are walking, and kept checking
> the remaining entries in the tree. You now immediately return, not
> seeing if the later entries in the tree are good and losing objects
> that are referenced by these entries as dangling.
>
> I am not sure if this is a good change. I suspect that the "bad
> mode" handling should be made less severe instead.
Makes sense. Replacement patch coming up. I'll pass on the mode
handling change, though (at least for now).
René
next prev parent reply other threads:[~2017-10-05 19:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-01 14:45 [PATCH] tag: avoid NULL pointer arithmetic René Scharfe
2017-10-02 4:13 ` Junio C Hamano
2017-10-02 5:08 ` Jeff King
2017-10-02 13:06 ` René Scharfe
2017-10-02 19:23 ` Jeff King
2017-10-03 10:22 ` SZEDER Gábor
2017-10-03 12:51 ` René Scharfe
2017-10-03 13:47 ` [PATCH] fsck: check results of lookup_blob() and lookup_tree() for NULL René Scharfe
2017-10-04 4:00 ` Junio C Hamano
2017-10-05 19:41 ` René Scharfe [this message]
2017-10-05 19:41 ` [PATCH v2] fsck: handle NULL return of lookup_blob() and lookup_tree() René Scharfe
2017-10-06 2:23 ` Junio C Hamano
2017-10-06 16:21 ` René Scharfe
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