From: Elijah Newren <newren@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
Git Mailing List <git@vger.kernel.org>,
Derrick Stolee <dstolee@microsoft.com>,
Jonathan Tan <jonathantanmy@google.com>,
Taylor Blau <me@ttaylorr.com>, Jeff King <peff@peff.net>,
Derrick Stolee <stolee@gmail.com>
Subject: Re: [PATCH v3 1/5] t4001: add a test comparing basename similarity and content similarity
Date: Sat, 13 Feb 2021 19:14:09 -0800 [thread overview]
Message-ID: <CABPp-BGYZBKhgLPSwGc0z+WO7UGAVS6A9W+cXoDn8nZDh2ZTJw@mail.gmail.com> (raw)
In-Reply-To: <CAPc5daVVNaBiWt8vRv3xrXd7GvNPwRGRF=W31DUJCnZRo+9qtA@mail.gmail.com>
On Sat, Feb 13, 2021 at 5:32 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> I do not consider "the same file changed in place" the same as "we
> seem to have lost a file in the old tree, ah, we found one that has
> the same basename in a different directory" at all, so your argument
> still does not make any sense to me, sorry.
I'm not set on the commit message wording, you asked why I had used
the terms I did and I tried to explain. I also explained how the
wording seemed to have helped Stolee understand.
If you'd like to suggest an alternative commit message, I'm happy to take it.
> 2021年2月13日(土) 17:25 Elijah Newren <newren@gmail.com>:
> >
> > On Sat, Feb 13, 2021 at 3:56 PM Junio C Hamano <gitster@pobox.com> wrote:
> > >
> > > Elijah Newren <newren@gmail.com> writes:
> > >
> > > > This is not true. If src/main.c is 99% similar to src/foo.c, and is
> > > > 0% similar to the src/main.c in the new commit, we match the old
> > > > src/main.c to the new src/main.c despite being far more similar
> > > > src/foo.c. Unless break detection is turned on, we do not allow
> > > > content similarity to trump (full) filename equality.
> > >
> > > Absolutely. And we are talking about a new optimization that kicks
> > > in only when there is no break or no copy detection going on, no?
> >
> > Yes, precisely, we are only considering cases without break
> > detection...and thus we are considering cases where for the last 15
> > years or more, sufficiently large filename similarity (an exact
> > fullname match) trumps any level of content similarity. I think it is
> > useful to note that while my optimization is adding more
> > considerations that can overrule maximal content similarity, it is not
> > the first such code choice to do that.
> >
> > But let me back up a bit...
> >
> > When I submitted the series, you and Stolee went into a long
> > discussion about an optimization that I didn't submit, one that feels
> > looser on "matching" than anything I submitted, and which I think
> > might counter-intuitively reduce performance rather than aid it. (The
> > performance side only comes into view in combination with later
> > series, but it was why I harped so much since then on only comparing
> > against at most one other file in the steps before full inexact rename
> > detection.) I was quite surprised by the diversion, but it made it
> > clear to me that my descriptions and commit messages were far too
> > vague and could be read to imply a completely different algorithm than
> > I intended. So, I tried to be far more careful in subsequent
> > iterations by adding wider context and contrasts.
> >
> > Further, after I wrote various things to try to clarify the
> > misunderstandings, I noticed that Stolee picked out one thing and
> > stated that "This idea of optimizing first for 100% filename
> > similarity is a good perspective on Git's rename detection algorithm."
> > (see https://lore.kernel.org/git/57d30e7d-7727-8d98-e3ef-bcfeebf9edd3@gmail.com/)
> > So, that particular point seemed to help him understand more, and
> > thus might be useful extra context for others reading along now or in
> > the future.
> >
> > Given all the above, I was trying to address earlier misunderstandings
> > and provide more context. Perhaps I swung the pendulum too far and
> > talked too much about other cases, or perhaps I just worded things
> > poorly again. All I was attempting to do in the commit message was
> > point out the multiple basic rules with filename and content
> > similarity, to lay the groundwork for new rules that do alternative
> > weightings.
> >
> > Anyway, I've added a few more tweaks to try to improve the wording for
> > the next round I'll submit today. Given my track record so far, it
> > would not be surprising if it still needed more tweaks.
next prev parent reply other threads:[~2021-02-14 3:16 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 22:52 [PATCH 0/3] Optimization batch 7: use file basenames to guide rename detection Elijah Newren via GitGitGadget
2021-02-06 22:52 ` [PATCH 1/3] diffcore-rename: compute basenames of all source and dest candidates Elijah Newren via GitGitGadget
2021-02-06 22:52 ` [PATCH 2/3] diffcore-rename: complete find_basename_matches() Elijah Newren via GitGitGadget
2021-02-06 22:52 ` [PATCH 3/3] diffcore-rename: guide inexact rename detection based on basenames Elijah Newren via GitGitGadget
2021-02-07 14:38 ` Derrick Stolee
2021-02-07 19:51 ` Junio C Hamano
2021-02-08 8:38 ` Elijah Newren
2021-02-08 11:43 ` Derrick Stolee
2021-02-08 16:25 ` Elijah Newren
2021-02-08 17:37 ` Junio C Hamano
2021-02-08 22:00 ` Elijah Newren
2021-02-08 23:43 ` Junio C Hamano
2021-02-08 23:52 ` Elijah Newren
2021-02-08 8:27 ` Elijah Newren
2021-02-08 11:31 ` Derrick Stolee
2021-02-08 16:09 ` Elijah Newren
2021-02-07 5:19 ` [PATCH 0/3] Optimization batch 7: use file basenames to guide rename detection Junio C Hamano
2021-02-07 6:05 ` Elijah Newren
2021-02-09 11:32 ` [PATCH v2 0/4] " Elijah Newren via GitGitGadget
2021-02-09 11:32 ` [PATCH v2 1/4] diffcore-rename: compute basenames of all source and dest candidates Elijah Newren via GitGitGadget
2021-02-09 13:17 ` Derrick Stolee
2021-02-09 16:56 ` Elijah Newren
2021-02-09 17:02 ` Derrick Stolee
2021-02-09 17:42 ` Elijah Newren
2021-02-09 11:32 ` [PATCH v2 2/4] diffcore-rename: complete find_basename_matches() Elijah Newren via GitGitGadget
2021-02-09 13:25 ` Derrick Stolee
2021-02-09 17:17 ` Elijah Newren
2021-02-09 17:34 ` Derrick Stolee
2021-02-09 11:32 ` [PATCH v2 3/4] diffcore-rename: guide inexact rename detection based on basenames Elijah Newren via GitGitGadget
2021-02-09 13:33 ` Derrick Stolee
2021-02-09 17:41 ` Elijah Newren
2021-02-09 18:59 ` Junio C Hamano
2021-02-09 11:32 ` [PATCH v2 4/4] gitdiffcore doc: mention new preliminary step for rename detection Elijah Newren via GitGitGadget
2021-02-09 12:59 ` Derrick Stolee
2021-02-09 17:03 ` Junio C Hamano
2021-02-09 17:44 ` Elijah Newren
2021-02-10 15:15 ` [PATCH v3 0/5] Optimization batch 7: use file basenames to guide " Elijah Newren via GitGitGadget
2021-02-10 15:15 ` [PATCH v3 1/5] t4001: add a test comparing basename similarity and content similarity Elijah Newren via GitGitGadget
2021-02-13 1:15 ` Junio C Hamano
2021-02-13 4:50 ` Elijah Newren
2021-02-13 23:56 ` Junio C Hamano
2021-02-14 1:24 ` Elijah Newren
2021-02-14 1:32 ` Junio C Hamano
2021-02-14 3:14 ` Elijah Newren [this message]
2021-02-10 15:15 ` [PATCH v3 2/5] diffcore-rename: compute basenames of all source and dest candidates Elijah Newren via GitGitGadget
2021-02-13 1:32 ` Junio C Hamano
2021-02-10 15:15 ` [PATCH v3 3/5] diffcore-rename: complete find_basename_matches() Elijah Newren via GitGitGadget
2021-02-13 1:48 ` Junio C Hamano
2021-02-13 18:34 ` Elijah Newren
2021-02-13 23:55 ` Junio C Hamano
2021-02-14 3:08 ` Elijah Newren
2021-02-10 15:15 ` [PATCH v3 4/5] diffcore-rename: guide inexact rename detection based on basenames Elijah Newren via GitGitGadget
2021-02-13 1:49 ` Junio C Hamano
2021-02-10 15:15 ` [PATCH v3 5/5] gitdiffcore doc: mention new preliminary step for rename detection Elijah Newren via GitGitGadget
2021-02-10 16:41 ` Junio C Hamano
2021-02-10 17:20 ` Elijah Newren
2021-02-11 8:15 ` [PATCH v4 0/6] Optimization batch 7: use file basenames to guide " Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 1/6] t4001: add a test comparing basename similarity and content similarity Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 2/6] diffcore-rename: compute basenames of all source and dest candidates Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 3/6] diffcore-rename: complete find_basename_matches() Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 4/6] diffcore-rename: guide inexact rename detection based on basenames Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 5/6] gitdiffcore doc: mention new preliminary step for rename detection Elijah Newren via GitGitGadget
2021-02-11 8:15 ` [PATCH v4 6/6] merge-ort: call diffcore_rename() directly Elijah Newren via GitGitGadget
2021-02-13 1:53 ` [PATCH v4 0/6] Optimization batch 7: use file basenames to guide rename detection Junio C Hamano
2021-02-14 7:51 ` [PATCH v5 " Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 1/6] t4001: add a test comparing basename similarity and content similarity Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 2/6] diffcore-rename: compute basenames of source and dest candidates Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 3/6] diffcore-rename: complete find_basename_matches() Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 4/6] diffcore-rename: guide inexact rename detection based on basenames Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 5/6] gitdiffcore doc: mention new preliminary step for rename detection Elijah Newren via GitGitGadget
2021-02-14 7:51 ` [PATCH v5 6/6] merge-ort: call diffcore_rename() directly Elijah Newren via GitGitGadget
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