From: Junio C Hamano <gitster@pobox•com>
To: Max Kirillov <max@max630•net>
Cc: Jeff King <peff@peff•net>,
Eric Sunshine <sunshine@sunshineco•com>,
git@vger•kernel.org
Subject: Re: [PATCH v5 1/3] blame: test to describe use of blame --reverse --first-parent
Date: Fri, 30 Oct 2015 15:30:38 -0700 [thread overview]
Message-ID: <xmqq611oj8fl.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <1446181313-15094-2-git-send-email-max@max630.net> (Max Kirillov's message of "Fri, 30 Oct 2015 07:01:51 +0200")
Max Kirillov <max@max630•net> writes:
> Reverse blame can be used to locate removal of lines which does not
> change adjacent lines. Such edits do not appear in non-reverse blame,
> because the adjacent lines last changed commit is older history, before
> the edit.
>
> For a big and active project which uses topic branches, or analogous
> feature, for example pull-requests, the history can contain many
> concurrent branches, and even after an edit merged into the target
> branch, there are still many (sometimes several tens or even hundreds)
> topic branch which do not contain it:
>
> a0--a1-----*a2-*a3-a4...-*a100
> |\ / / /
> | b0-B1..bN / /
> |\ / /
> | c0.. ..cN /
> \ /
> z0.. ..zN
>
> Here, the '*'s mark the first parent in merge, and uppercase B1 - the
> commit where the line being blamed for was removed. Since commits cN-zN
> do not contain the B1, the still have the line removed in B1, and
> reverce blame can report that the last commit for the line was zN
> (meaning that it was removed in a100). In fact it really does return
> some very late commit, and this makes it unusable for finding the B1
> commit.
>
> The search could be done by blame --reverse --first-parent. For range
> a0..a100 it would return a1, and then only one additional blame along
> the a0..bN will return the desired commit b0. But combining --reverse
> and --first-parent was forbidden in 95a4fb0eac, because incorrectly
> specified range could produce unexpected and meaningless result.
>
> Add test which describes the expected behavior of
> `blame --reverse --first-parent` in the case described above.
>
> Signed-off-by: Max Kirillov <max@max630•net>
> ---
There were a few obvious typos I spotted but other than that a very
understandable description. Will queue.
Thanks.
> t/t8009-blame-vs-topicbranches.sh | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
> create mode 100755 t/t8009-blame-vs-topicbranches.sh
>
> diff --git a/t/t8009-blame-vs-topicbranches.sh b/t/t8009-blame-vs-topicbranches.sh
> new file mode 100755
> index 0000000..175ad37
> --- /dev/null
> +++ b/t/t8009-blame-vs-topicbranches.sh
> @@ -0,0 +1,36 @@
> +#!/bin/sh
> +
> +test_description='blaming trough history with topic branches'
> +. ./test-lib.sh
> +
> +# Creates the history shown below. '*'s mark the first parent in the merges.
> +# The only line of file.t is changed in commit B2
> +#
> +# +---C1
> +# / \
> +# A0--A1--*A2--*A3
> +# \ /
> +# B1-B2
> +#
> +test_expect_success setup '
> + test_commit A0 file.t line0 &&
> + test_commit A1 &&
> + git reset --hard A0 &&
> + test_commit B1 &&
> + test_commit B2 file.t line0changed &&
> + git reset --hard A1 &&
> + test_merge A2 B2 &&
> + git reset --hard A1 &&
> + test_commit C1 &&
> + git reset --hard A2 &&
> + test_merge A3 C1
> + '
> +
> +test_expect_failure 'blame --reverse --first-parent finds A1' '
> + git blame --porcelain --reverse --first-parent A0..A3 -- file.t >actual_full &&
> + head -n 1 <actual_full | sed -e "s/ .*//" >actual &&
> + git rev-parse A1 >expect &&
> + test_cmp expect actual
> + '
> +
> +test_done
next prev parent reply other threads:[~2015-10-30 22:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-21 4:08 [PATCH 0/2] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-21 4:08 ` [PATCH 1/2] Add test to describe expectation of blame --reverse with branched history Max Kirillov
2015-10-21 4:08 ` [PATCH 2/2] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-21 4:29 ` Eric Sunshine
2015-10-22 3:52 ` Max Kirillov
2015-10-22 3:51 ` [PATCH v2 0/2] " Max Kirillov
2015-10-22 3:51 ` [PATCH v2 1/2] Add test to describe expectation of blame --reverse with branched history Max Kirillov
2015-10-22 4:19 ` Junio C Hamano
2015-10-22 14:37 ` Max Kirillov
2015-10-22 14:56 ` Max Kirillov
2015-10-22 3:51 ` [PATCH v2 2/2] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-22 4:25 ` Junio C Hamano
2015-10-22 14:56 ` Max Kirillov
2015-10-22 19:11 ` Junio C Hamano
2015-10-25 12:43 ` Max Kirillov
2015-10-25 16:52 ` Junio C Hamano
2015-10-22 4:07 ` [PATCH v3 0/2] " Max Kirillov
2015-10-22 4:07 ` [PATCH v3 1/2] Add test to describe expectation of blame --reverse with branched history Max Kirillov
2015-10-22 4:07 ` [PATCH v3 2/2] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-26 5:26 ` [PATCH v4 0/4] " Max Kirillov
2015-10-26 5:26 ` [PATCH v4 1/3] Add test to describe expectation of blame --reverse with branched history Max Kirillov
2015-10-26 5:41 ` Max Kirillov
2015-10-26 6:27 ` Junio C Hamano
2015-10-27 4:40 ` Max Kirillov
2015-10-27 17:57 ` Junio C Hamano
2015-10-26 5:26 ` [PATCH v4 2/3] blame: extract find_single_final Max Kirillov
2015-10-26 5:26 ` [PATCH v4 3/3] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-30 5:01 ` [PATCH v5 0/3] " Max Kirillov
2015-10-30 5:01 ` [PATCH v5 1/3] blame: test to describe use of blame --reverse --first-parent Max Kirillov
2015-10-30 22:30 ` Junio C Hamano [this message]
2015-10-30 5:01 ` [PATCH v5 2/3] blame: extract find_single_final Max Kirillov
2015-10-30 5:01 ` [PATCH v5 3/3] blame: allow blame --reverse --first-parent when it makes sense Max Kirillov
2015-10-26 5:26 ` [PATCH v4 0/4] " Max Kirillov
2015-10-26 5:31 ` Max Kirillov
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