Re: [PATCH v4 3/3] ls-files: add --deduplicate option

From: 胡哲宁 <adlternative@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: ZheNing Hu via GitGitGadget <gitgitgadget@gmail.com>,
	Git List <git@vger.kernel.org>,
	Eric Sunshine <sunshine@sunshineco.com>
Subject: Re: [PATCH v4 3/3] ls-files: add --deduplicate option
Date: Mon, 18 Jan 2021 12:09:51 +0800	[thread overview]
Message-ID: <CAOLTT8Syp2ZeTXW-m+e=dn2W773nScB_kwZLS3MjLTcFQ_bctw@mail.gmail.com> (raw)
In-Reply-To: <xmqqbldnkuja.fsf@gitster.c.googlers.com>

Junio C Hamano <gitster@pobox.com> 于2021年1月18日周一 上午7:34写道：
>
> "ZheNing Hu via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > diff --git a/t/t3012-ls-files-dedup.sh b/t/t3012-ls-files-dedup.sh
> > new file mode 100755
> > index 00000000000..75877255c2c
> > --- /dev/null
> > +++ b/t/t3012-ls-files-dedup.sh
> > @@ -0,0 +1,57 @@
> > +#!/bin/sh
> > +
> > +test_description='git ls-files --deduplicate test'
> > +
> > +. ./test-lib.sh
>
> We should already have a ls-files test so that we can add a handful
> new tests to it, instead of dedicating a whole new test script.
>
Fine,It might be easier for me to write a test file myself for the time being.
But I will learn slowly.
> Also, don't do everything in a single 'setup'.  There are various
> scenarios you want to make sure ls-files to work (grep for ls-files
> in the following you added---I count 4 of them), and when a future
> developer touches the code, he or she may break one but not other
> three.  The purpose you write tests is to protect your new feature
> from such a developer *AND* help such a developer to debug and fix
> his or her changes.  For that, it would be a lot more sensible to
> have one set-up that is common, and then four separate tests.
>
> > +test_expect_success 'setup' '
> > +     >a.txt &&
> > +     >b.txt &&
> > +     >delete.txt &&
> > +     git add a.txt b.txt delete.txt &&
> > +     git commit -m master:1 &&
>
> Needless use of the word "master".  Observe what is going on in the
> project around you and avoid stepping other peoples' toes.  One of
> the ongoing effort is to grep for the phrase master in t/ directory
> and examine what happens when the default initial branch name
> becomes something other than 'master', so adding a needless hit like
> this is most unwelcome.
>
Well, I will try my best to use less "master".
> > +     echo a >a.txt &&
> > +     echo b >b.txt &&
> > +     echo delete >delete.txt &&
> > +     git add a.txt b.txt delete.txt &&
> > +     git commit -m master:2 &&
>
> > +     git checkout HEAD~ &&
> > +     git switch -c dev &&
>
> Needless mixture of checkout/switch.  If you switch branches using
> "git checkout", for example, consistently do so, i.e.
>
>         git checkout -b dev HEAD~1
>
> It's not like these new tests are to test checkout and switch; your
> mission is to protect "ls-files --dedup" feature here.
>
> > +     test_when_finished "git switch master" &&
> > +     echo change >a.txt &&
> > +     git add a.txt &&
> > +     git commit -m dev:1 &&
>
> I'd consider all of the above to be 'setup' that is common for
> subsequent tests.  It may make sense to actually do everything
> on the initial branch, i.e. after creating two commits, do
>
I understand it now...setup is for serve as a basis for other tests.
>         git tag tip &&
>         git reset --hard HEAD^ &&
>         echo change >a.txt &&
>         git commit -a -m side &&
>         git tag side
>
> You are always on the initial branch without ever switching, so
> there is no need for the when_finished stuff.
>
> Then the first of your test is to show the index with conflicts.
>
> > +     test_must_fail git merge master &&
>
> This will become "git merge tip" instead of 'master'.
>
use tag instead of use branch name...
> > +     git ls-files --deduplicate >actual &&
> > +     cat >expect <<-\EOF &&
> > +     a.txt
> > +     b.txt
> > +     delete.txt
> > +     EOF
> > +     test_cmp expect actual &&
>
> And up to this point is the first test after 'setup'.
>
> The next test should begin with:
>
>         git reset --hard side &&
>         test_must_fail git merge tip &&
>
> so that even when the first test is skipped, or left unmerged,
> you'll begin with a known state.
>
Well,I understand now that the a test_success should allow other
programmers to skip this test,so that we should reset to a known
state at the beginning of each test.
> > +     rm delete.txt &&
> > +     git ls-files -d -m --deduplicate >actual &&
> > +     cat >expect <<-\EOF &&
> > +     a.txt
> > +     delete.txt
> > +     EOF
> > +     test_cmp expect actual &&
> > +     git ls-files -d -m -t  --deduplicate >actual &&
> > +     cat >expect <<-\EOF &&
> > +     C a.txt
> > +     C a.txt
> > +     C a.txt
> > +     R delete.txt
> > +     C delete.txt
> > +     EOF
> > +     test_cmp expect actual &&
> > +     git ls-files -d -m -c  --deduplicate >actual &&
> > +     cat >expect <<-\EOF &&
> > +     a.txt
> > +     b.txt
> > +     delete.txt
> > +     EOF
> > +     test_cmp expect actual &&
>
> These three can be kept in the same test_expect_success, as they are
> exercising read-only operation on the same state but with different
> display options.
>
indeed so.
> But in this case, the preparation is not too tedious (just a failed
> merge plus a deletion), so you probably would prefer to split it
> into 3 independent tests---that may make it more helpful to future
> developers.
>
Thanks:)
> > +     git merge --abort
> > +'
> > +test_done