From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, Derrick Stolee <derrickstolee@github.com>
Subject: Re: [PATCH 1/2] notes: clean up confusing NULL checks in init_notes()
Date: Mon, 24 Apr 2023 11:05:49 -0700 [thread overview]
Message-ID: <xmqqttx5duki.fsf@gitster.g> (raw)
In-Reply-To: <20230422135543.GA3942829@coredump.intra.peff.net> (Jeff King's message of "Sat, 22 Apr 2023 09:55:43 -0400")
Jeff King <peff@peff.net> writes:
> Coverity complains that we check whether "notes_ref" is NULL, but it was
> already implied to be non-NULL earlier in the function. And this is
> true; since b9342b3fd63 (refs: add array of ref namespaces, 2022-08-05),
> we call xstrdup(notes_ref) unconditionally, which would segfault if it
> was NULL.
>
> But that commit is actually doing the right thing. Even if NULL is
> passed into the function, we'll use default_notes_ref() as a fallback,
> which will never return NULL (it tries a few options, but its last
> resort is a string literal). Ironically, the "!notes_ref" check was
> added by the same commit that added the fallback: 709f79b0894 (Notes
> API: init_notes(): Initialize the notes tree from the given notes ref,
> 2010-02-13). So this check never did anything.
I am impressed(?) that Coverity can complain at the "_or_null" part
in xstrdup_or_null().
It all makes sense. Thanks.
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> notes.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/notes.c b/notes.c
> index 45fb7f22d1..cadb435056 100644
> --- a/notes.c
> +++ b/notes.c
> @@ -1019,13 +1019,13 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
> t->root = (struct int_node *) xcalloc(1, sizeof(struct int_node));
> t->first_non_note = NULL;
> t->prev_non_note = NULL;
> - t->ref = xstrdup_or_null(notes_ref);
> + t->ref = xstrdup(notes_ref);
> t->update_ref = (flags & NOTES_INIT_WRITABLE) ? t->ref : NULL;
> t->combine_notes = combine_notes;
> t->initialized = 1;
> t->dirty = 0;
>
> - if (flags & NOTES_INIT_EMPTY || !notes_ref ||
> + if (flags & NOTES_INIT_EMPTY ||
> repo_get_oid_treeish(the_repository, notes_ref, &object_oid))
> return;
> if (flags & NOTES_INIT_WRITABLE && read_ref(notes_ref, &object_oid))
next prev parent reply other threads:[~2023-04-24 18:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-22 13:54 [PATCH 0/2] coverity null-check fixes Jeff King
2023-04-22 13:55 ` [PATCH 1/2] notes: clean up confusing NULL checks in init_notes() Jeff King
2023-04-24 18:05 ` Junio C Hamano [this message]
2023-04-24 21:57 ` Jeff King
2023-04-22 13:56 ` [PATCH 2/2] fetch_bundle_uri(): drop pointless NULL check Jeff King
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