From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, me@ttaylorr.com, gitster@pobox.com,
abhishekkumar8222@gmail.com,
Derrick Stolee <derrickstolee@github.com>
Subject: Re: [PATCH v2 4/4] commit-graph: fix generation number v2 overflow values
Date: Mon, 28 Feb 2022 16:40:26 +0100 [thread overview]
Message-ID: <220228.868rtv3sfx.gmgdl@evledraar.gmail.com> (raw)
In-Reply-To: <193217c71e0aaf3f56a02d9abec6753bd19aba71.1646056423.git.gitgitgadget@gmail.com>
On Mon, Feb 28 2022, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <derrickstolee@github.com>
>
> The Generation Data Chunk was implemented and tested in e8b63005c
> (commit-graph: implement generation data chunk, 2021-01-16), but the
> test was carefully constructed to work on systems with 32-bit dates.
> Since the corrected commit date offsets still required more than 31
> bits, this triggered writing the generation_data_overflow chunk.
>
> However, upon closer look, the
> write_graph_chunk_generation_data_overflow() method writes the offsets
> to the chunk (as dictated by the format) but fill_commit_graph_info()
> treats the value in the chunk as if it is the full corrected commit date
> (not an offset). For some reason, this does not cause an issue when
> using the FUTURE_DATE specified in t5318-commit-graph.sh, but it does
> show up as a failure in 'git commit-graph verify' if we increase that
> FUTURE_DATE to be above four billion.
>
> Fix this error and update the test to require 64-bit dates so we can
> safely use this large value in our test.
Hrm, so perhaps re my comment on 2/4 @2147483646 was never used? I'm not
sure I understand this.
> diff --git a/commit-graph.c b/commit-graph.c
> index 8e52bb09552..b86a6a634fe 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -806,7 +806,7 @@ static void fill_commit_graph_info(struct commit *item, struct commit_graph *g,
> die(_("commit-graph requires overflow generation data but has none"));
>
> offset_pos = offset ^ CORRECTED_COMMIT_DATE_OFFSET_OVERFLOW;
> - graph_data->generation = get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);
> + graph_data->generation = item->date + get_be64(g->chunk_generation_data_overflow + 8 * offset_pos);
> } else
> graph_data->generation = item->date + offset;
> } else
> diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
> index 1afee1c2705..f4ffaad661d 100755
> --- a/t/t5318-commit-graph.sh
> +++ b/t/t5318-commit-graph.sh
> @@ -815,6 +815,15 @@ test_expect_success 'corrupt commit-graph write (missing tree)' '
> )
> '
This goes back to my comment on 3/4 but:
> +# The remaining tests check timestamps that flow over
> +# 32-bits. The graph_git_behavior checks can't take a
> +# prereq, so just stop here if we are on a 32-bit machine.
> +
> +if ! test_have_prereq TIME_IS_64BIT || ! test_have_prereq TIME_T_IS_64BIT
> +then
> + test_done
> +fi
> +
This...(continued)...
> # We test the overflow-related code with the following repo history:
> #
> # 4:F - 5:N - 6:U
> @@ -832,10 +841,10 @@ test_expect_success 'corrupt commit-graph write (missing tree)' '
> # The largest offset observed is 2 ^ 31, just large enough to overflow.
> #
>
> -test_expect_success 'set up and verify repo with generation data overflow chunk' '
> +test_expect_success TIME_IS_64BIT,TIME_T_IS_64BIT 'set up and verify repo with generation data overflow chunk' '
> objdir=".git/objects" &&
> UNIX_EPOCH_ZERO="@0 +0000" &&
> - FUTURE_DATE="@2147483646 +0000" &&
> + FUTURE_DATE="@4000000000 +0000" &&
Hrm, again this may be over my head, but @4147483646 instead of
@2147483646 in the other test, but @4000000000 instead of the same here?
> test_oid_cache <<-EOF &&
> oid_version sha1:1
> oid_version sha256:2
> @@ -867,4 +876,8 @@ test_expect_success 'set up and verify repo with generation data overflow chunk'
>
> graph_git_behavior 'generation data overflow chunk repo' repo left right
>
> +# Do not add tests at the end of this file, unless they require 64-bit
> +# timestamps, since this portion of the script is only executed when
> +# time data types have 64 bits.
> +
> test_done
...and this would really be much nicer if we split this test up into its
own file, which would be obviously named to note the
issue. tXXXX-commit-graph-64bit-timestamp.sh or something.
As shown in my recent 0a2bfccb9c8 (t0051: use "skip_all" under !MINGW in
single-test file, 2022-02-04) you'll also get much nicer output from
"prove" in that case.
next prev parent reply other threads:[~2022-02-28 15:46 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 20:38 [PATCH 0/7] Commit-graph: Generation Number v2 Fixes, v3 implementation Derrick Stolee via GitGitGadget
2022-02-24 20:38 ` [PATCH 1/7] test-read-graph: include extra post-parse info Derrick Stolee via GitGitGadget
2022-02-24 20:38 ` [PATCH 2/7] commit-graph: fix ordering bug in generation numbers Derrick Stolee via GitGitGadget
2022-02-24 22:15 ` Junio C Hamano
2022-02-25 13:51 ` Derrick Stolee
2022-02-25 17:35 ` Junio C Hamano
2022-02-24 20:38 ` [PATCH 3/7] commit-graph: start parsing generation v2 (again) Derrick Stolee via GitGitGadget
2022-02-28 15:18 ` Patrick Steinhardt
2022-02-28 16:23 ` Derrick Stolee
2022-02-28 16:59 ` Patrick Steinhardt
2022-02-28 18:44 ` Derrick Stolee
2022-03-01 9:46 ` Patrick Steinhardt
2022-03-01 10:35 ` Patrick Steinhardt
2022-03-01 14:06 ` Derrick Stolee
2022-03-01 14:53 ` Patrick Steinhardt
2022-03-01 15:25 ` Derrick Stolee
2022-03-02 13:57 ` Patrick Steinhardt
2022-03-02 14:57 ` Derrick Stolee
2022-03-02 18:15 ` Junio C Hamano
2022-03-02 18:46 ` Derrick Stolee
2022-03-02 22:42 ` Junio C Hamano
2022-03-03 11:19 ` Patrick Steinhardt
2022-03-03 16:00 ` Derrick Stolee
2022-03-04 14:03 ` Derrick Stolee
2022-03-07 10:34 ` Patrick Steinhardt
2022-03-07 13:45 ` Derrick Stolee
2022-03-07 17:22 ` Junio C Hamano
2022-03-10 13:58 ` Patrick Steinhardt
2022-03-10 17:18 ` Derrick Stolee
2022-02-24 20:38 ` [PATCH 4/7] commit-graph: fix generation number v2 overflow values Derrick Stolee via GitGitGadget
2022-02-24 22:35 ` Junio C Hamano
2022-02-25 13:53 ` Derrick Stolee
2022-02-25 17:38 ` Junio C Hamano
2022-02-24 20:38 ` [PATCH 5/7] commit-graph: document file format v2 Derrick Stolee via GitGitGadget
2022-02-24 22:55 ` Junio C Hamano
2022-02-25 22:31 ` Ævar Arnfjörð Bjarmason
2022-02-28 13:44 ` Derrick Stolee
2022-02-28 14:27 ` Ævar Arnfjörð Bjarmason
2022-02-28 16:39 ` Derrick Stolee
2022-02-28 21:14 ` Ævar Arnfjörð Bjarmason
2022-03-01 14:19 ` Derrick Stolee
2022-03-01 14:29 ` Ævar Arnfjörð Bjarmason
2022-03-01 15:59 ` Derrick Stolee
2022-02-24 20:38 ` [PATCH 6/7] commit-graph: parse " Derrick Stolee via GitGitGadget
2022-02-24 23:01 ` Junio C Hamano
2022-02-25 13:54 ` Derrick Stolee
2022-02-24 20:38 ` [PATCH 7/7] commit-graph: write " Derrick Stolee via GitGitGadget
2022-02-24 21:42 ` [PATCH 0/7] Commit-graph: Generation Number v2 Fixes, v3 implementation Junio C Hamano
2022-02-24 23:06 ` Junio C Hamano
2022-02-25 13:55 ` Derrick Stolee
2022-02-28 13:53 ` [PATCH v2 0/4] Commit-graph: Generation Number v2 Fixes Derrick Stolee via GitGitGadget
2022-02-28 13:53 ` [PATCH v2 1/4] test-read-graph: include extra post-parse info Derrick Stolee via GitGitGadget
2022-02-28 15:22 ` Ævar Arnfjörð Bjarmason
2022-02-28 13:53 ` [PATCH v2 2/4] commit-graph: fix ordering bug in generation numbers Derrick Stolee via GitGitGadget
2022-02-28 15:25 ` Ævar Arnfjörð Bjarmason
2022-02-28 13:53 ` [PATCH v2 3/4] commit-graph: start parsing generation v2 (again) Derrick Stolee via GitGitGadget
2022-02-28 15:30 ` Ævar Arnfjörð Bjarmason
2022-02-28 16:43 ` Derrick Stolee
2022-02-28 13:53 ` [PATCH v2 4/4] commit-graph: fix generation number v2 overflow values Derrick Stolee via GitGitGadget
2022-02-28 15:40 ` Ævar Arnfjörð Bjarmason [this message]
2022-03-01 17:23 ` [PATCH v2 0/4] Commit-graph: Generation Number v2 Fixes Ævar Arnfjörð Bjarmason
2022-03-01 19:48 ` [PATCH v3 0/5] " Derrick Stolee via GitGitGadget
2022-03-01 19:48 ` [PATCH v3 1/5] test-read-graph: include extra post-parse info Derrick Stolee via GitGitGadget
2022-03-01 19:48 ` [PATCH v3 2/5] t5318: extract helpers to lib-commit-graph.sh Derrick Stolee via GitGitGadget
2022-03-01 19:48 ` [PATCH v3 3/5] commit-graph: fix ordering bug in generation numbers Derrick Stolee via GitGitGadget
2022-03-01 20:13 ` Junio C Hamano
2022-03-01 20:30 ` Junio C Hamano
2022-03-02 14:13 ` Derrick Stolee
2022-03-01 19:48 ` [PATCH v3 4/5] commit-graph: start parsing generation v2 (again) Derrick Stolee via GitGitGadget
2022-03-01 19:48 ` [PATCH v3 5/5] commit-graph: fix generation number v2 overflow values Derrick Stolee via GitGitGadget
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