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From: Junio C Hamano <gitster@pobox•com>
To: "John Cai via GitGitGadget" <gitgitgadget@gmail•com>
Cc: git@vger•kernel.org,  Jeff King <peff@peff•net>,
	 Jonathan Tan <jonathantanmy@google•com>,
	 Eric Sunshine <sunshine@sunshineco•com>,
	John Cai <johncai86@gmail•com>
Subject: Re: [PATCH v5 0/2] attr: add attr.tree config
Date: Fri, 13 Oct 2023 13:31:19 -0700	[thread overview]
Message-ID: <xmqqa5smz2lk.fsf@gitster.g> (raw)
In-Reply-To: <xmqqmswmz76w.fsf@gitster.g> (Junio C. Hamano's message of "Fri, 13 Oct 2023 11:52:07 -0700")

Junio C Hamano <gitster@pobox•com> writes:

> 	if (repo_get_oid_treeish(the_repository,
> 				 default_attr_source_tree_object_name,
> 				 attr_source) && !ignore_bad_attr_tree)
> 		die(_("bad --attr-source or GIT_ATTR_SOURCE"));
>
> OOPS!  Sorry for not noticing earlier, but repo_get_oid_treeish()
> does *NOT* error out when the discovered object is not a treeish, as
> the suggested object type is merely supplied for disambiguation
> purposes (e.g., with objects 012345 that is a tree and 012346 that
> is a blob, you can still ask for treeish "01234" but if you ask for
> an object "01234" it will fail).
>
> So, the alternative test would have caught this bug, no?  Instead of
> silently treating the non-treeish as an empty tree, we would have
> died much later when the object supposedly a tree-ish turns out to
> be a blob, or something?

There indeed is a bug, but not really.  If we add this test:

test_expect_success 'attr.tree that points at a non-treeish' '
	test_when_finished rm -rf empty &&
	git init empty &&
	(
		cd empty &&
		echo "f/path: test: unspecified" >expect &&
		H=$(git hash-object -t blob --stdin -w </dev/null) &&
		git -c attr.tree=$H check-attr test -- f/path >actual 2>err &&
		test_must_be_empty err &&
		test_cmp expect actual
	)
'

repo_get_oid_treeish() returns a blob object name and we end up
storing a blob object name in "attr_source" static variable of
default_attr_source() function.

Later this is fed to read_attr() by bootstrap_attr_stack() and then
to read_attr_from_blob() that uses it to call get_tree_entry(),
which fails for any path because it is a blob.  We do not give any
errors or error messages during the whole process.

So in a sense, for !!ignore_bad_attr_tree case, the code ends up
doing the right thing.  But if !ignore_bad_attr_tree is true, i.e.,
a blob object name is given via --attr-source or GIT_ATTR_SOURCE,
then the bug will be uncovered.

 t/t0003-attributes.sh | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git c/t/t0003-attributes.sh w/t/t0003-attributes.sh
index ecf43ab545..0f02f22171 100755
--- c/t/t0003-attributes.sh
+++ w/t/t0003-attributes.sh
@@ -394,6 +394,18 @@ test_expect_success 'bare repo defaults to reading .gitattributes from HEAD' '
 	test_cmp expect actual
 '
 
+test_expect_success '--attr-source that points at a non-treeish' '
+	test_when_finished rm -rf empty &&
+	git init empty &&
+	(
+		cd empty &&
+		echo "$bad_attr_source_err" >expect_err &&
+		H=$(git hash-object -t blob --stdin -w </dev/null) &&
+		test_must_fail git --attr-source=$H check-attr test -- f/path 2>err &&
+		test_cmp expect_err err
+	)
+'
+
 test_expect_success 'precedence of --attr-source, GIT_ATTR_SOURCE, then attr.tree' '
 	test_when_finished rm -rf empty &&
 	git init empty &&


  reply	other threads:[~2023-10-13 20:31 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20 14:00 [PATCH] attr: attr.allowInvalidSource config to allow invalid revision John Cai via GitGitGadget
2023-09-20 16:06 ` Junio C Hamano
2023-09-21  4:15   ` Jeff King
2023-09-21  8:52     ` Junio C Hamano
2023-09-21 21:40       ` Jeff King
2023-09-26 18:27         ` John Cai
2023-09-26 18:30       ` John Cai
2023-09-26 18:23     ` John Cai
2023-10-04 18:18 ` [PATCH v2 0/2] attr: add attr.tree and attr.allowInvalidSource configs John Cai via GitGitGadget
2023-10-04 18:18   ` [PATCH v2 1/2] attr: add attr.tree for setting the treeish to read attributes from John Cai via GitGitGadget
2023-10-04 19:58     ` Junio C Hamano
2023-10-05 17:07       ` Jeff King
2023-10-05 19:46         ` John Cai
2023-10-04 23:45     ` Junio C Hamano
2023-10-06 17:20       ` Jonathan Tan
2023-10-04 18:18   ` [PATCH v2 2/2] attr: add attr.allowInvalidSource config to allow invalid revision John Cai via GitGitGadget
2023-10-10 19:49   ` [PATCH v3 0/2] attr: add attr.tree config John Cai via GitGitGadget
2023-10-10 19:49     ` [PATCH v3 1/2] attr: read attributes from HEAD when bare repo John Cai via GitGitGadget
2023-10-10 19:58       ` Eric Sunshine
2023-10-10 19:49     ` [PATCH v3 2/2] attr: add attr.tree for setting the treeish to read attributes from John Cai via GitGitGadget
2023-10-10 22:14       ` Junio C Hamano
2023-10-11  2:19         ` John Cai
2023-10-11 17:13     ` [PATCH v4 0/2] attr: add attr.tree config John Cai via GitGitGadget
2023-10-11 17:13       ` [PATCH v4 1/2] attr: read attributes from HEAD when bare repo John Cai via GitGitGadget
2023-10-11 17:13       ` [PATCH v4 2/2] attr: add attr.tree for setting the treeish to read attributes from John Cai via GitGitGadget
2023-10-11 22:09       ` [PATCH v4 0/2] attr: add attr.tree config Junio C Hamano
2023-10-13 15:30         ` John Cai
2023-10-13 17:39       ` [PATCH v5 " John Cai via GitGitGadget
2023-10-13 17:39         ` [PATCH v5 1/2] attr: read attributes from HEAD when bare repo John Cai via GitGitGadget
2023-10-13 17:39         ` [PATCH v5 2/2] attr: add attr.tree for setting the treeish to read attributes from John Cai via GitGitGadget
2023-10-13 18:52         ` [PATCH v5 0/2] attr: add attr.tree config Junio C Hamano
2023-10-13 20:31           ` Junio C Hamano [this message]
2023-10-13 20:47             ` Junio C Hamano
2023-10-19 15:43               ` John Cai

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