From: Junio C Hamano Date: Mon, 24 Apr 2023 18:05:49 GMT Subject: Re: [PATCH 1/2] notes: clean up confusing NULL checks in init_notes() Message-ID: In-Reply-To: <20230422135543.GA3942829@coredump.intra.peff.net> Jeff King 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 > --- > 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))