bug#70456: Request for merging core-updates branch

bug#70456: Request for merging core-updates branch

[Steve George]

Let's see where we are with the branch currently.

Thanks,

Steve / Futurile

bug#70456: Request for merging "core-updates" branch

[Christopher Baines]

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Hey,

Thanks for raising this issue Steve, given the branch has been going for
around 9 months (since [1]) now, I think it's well overdue to start
looking at building and merging it.

1: https://lists.gnu.org/archive/html/guix-commits/2023-07/msg00332.html

I pushed a single commit plus a merge from master today, and that was
pretty difficult. There was plenty of conflicts, and I probably have
resolved some wrongly, and there's potentially some things that Git
didn't raise as conflicts but might have broken with merging in master.

I'm also really confused by what commits appear to be on the branch,
take 12b15585a75062f3fba09d82861c6fae9a7743b2 which appears to be one
core-updates, but it's a duplicate of
e2a7c227dea5b361e2ebdbba24b923d1922a79d0 which was pushed to
master. Same with this commit 28d14130953d868d4848540d9de8e1ae4a01a467,
which is different to f29f80c194d0c534a92354b2bc19022a9b70ecf8 on
master.

Putting aside the functional changes on core-updates, it's doesn't seem
good to merge these seemingly duplicate commits on to master. I'm not
sure how this happened though, or how to fix it.

Chris

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bug#70456: Request for merging "core-updates" branch

[Christopher Baines]

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Christopher Baines <mail@cbaines.net> writes:

> I'm also really confused by what commits appear to be on the branch,
> take 12b15585a75062f3fba09d82861c6fae9a7743b2 which appears to be one
> core-updates, but it's a duplicate of
> e2a7c227dea5b361e2ebdbba24b923d1922a79d0 which was pushed to
> master. Same with this commit 28d14130953d868d4848540d9de8e1ae4a01a467,
> which is different to f29f80c194d0c534a92354b2bc19022a9b70ecf8 on
> master.

I've worked out at least when these two werid commits turned up on
core-updates.

12b15585a7 is mentioned here:
  https://lists.gnu.org/archive/html/guix-commits/2023-09/msg00955.html

and 28d1413095 is mentioned here:
  https://lists.gnu.org/archive/html/guix-commits/2024-03/msg00381.html


With the changes last month in March, I was going to suggest deleting
the branch and then re-creating from f205179ed2 and trying to re-apply
the changes that should be on core-updates, while avoiding any
"duplicate" commits. However, I'm not even sure where to being with the
~5000 commits pushed in September, at least one of them is a duplicate
of a commit on master, but I'm not sure how many of the other ~5000 are.

For comparison, I did a merge of master in to core-updates today, and
this is what it shows up like on guix-commits:

  https://lists.gnu.org/archive/html/guix-commits/2024-04/msg01209.html

There are only two new revisions, the ed update I pushed, and the merge
commit, which is what a merge should look like as far as I'm aware.

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bug#70456: Request for merging "core-updates" branch

[Maxim Cournoyer]

Hi,

Christopher Baines <mail@cbaines.net> writes:

> Christopher Baines <mail@cbaines.net> writes:
>
>> I'm also really confused by what commits appear to be on the branch,
>> take 12b15585a75062f3fba09d82861c6fae9a7743b2 which appears to be one
>> core-updates, but it's a duplicate of
>> e2a7c227dea5b361e2ebdbba24b923d1922a79d0 which was pushed to
>> master. Same with this commit 28d14130953d868d4848540d9de8e1ae4a01a467,
>> which is different to f29f80c194d0c534a92354b2bc19022a9b70ecf8 on
>> master.
>
> I've worked out at least when these two werid commits turned up on
> core-updates.
>
> 12b15585a7 is mentioned here:
>   https://lists.gnu.org/archive/html/guix-commits/2023-09/msg00955.html
>
> and 28d1413095 is mentioned here:
>   https://lists.gnu.org/archive/html/guix-commits/2024-03/msg00381.html
>
>
> With the changes last month in March, I was going to suggest deleting
> the branch and then re-creating from f205179ed2 and trying to re-apply
> the changes that should be on core-updates, while avoiding any
> "duplicate" commits. However, I'm not even sure where to being with the
> ~5000 commits pushed in September, at least one of them is a duplicate
> of a commit on master, but I'm not sure how many of the other ~5000 are.
>
> For comparison, I did a merge of master in to core-updates today, and
> this is what it shows up like on guix-commits:
>
>   https://lists.gnu.org/archive/html/guix-commits/2024-04/msg01209.html
>
> There are only two new revisions, the ed update I pushed, and the merge
> commit, which is what a merge should look like as far as I'm aware.

I think probably what happened is that in the middle of a merge of
master -> core-updates (which entails sometimes painful conflicts
resolution), a new commit pushed to core-updates, and to be able to push
the resulting local branch (including the thousands of commits from the
merge commit) got rebased on the remote core-updates.

Perhaps another merge commit appeared on the remote around the same
time, which would explain the duplicates.

While I agree it's messy to have 5000 of duplicated commits, I'm not
sure attempting to rewrite the branch, which has seen a lot of original
commits, is a good idea (it'd be easy to have some good commits fall
into cracks, leading to lost of work).

I'd rather we take this experience as a strong reminding that rebasing
merge commits should be avoided at all costs (git already issues a
warning, IIRC).  As you suggested, the next time a situation like this
happens (locally prepared merge commit with new commits made to the
remote branch), merging the remote into the local branch is probably a
nicer solution.

-- 
Thanks,
Maxim

bug#70456: Request for merging "core-updates" branch

[Christopher Baines]

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Maxim Cournoyer <maxim.cournoyer@gmail.com> writes:

> Hi,
>
> Christopher Baines <mail@cbaines.net> writes:
>
>> Christopher Baines <mail@cbaines.net> writes:
>>
>>> I'm also really confused by what commits appear to be on the branch,
>>> take 12b15585a75062f3fba09d82861c6fae9a7743b2 which appears to be one
>>> core-updates, but it's a duplicate of
>>> e2a7c227dea5b361e2ebdbba24b923d1922a79d0 which was pushed to
>>> master. Same with this commit 28d14130953d868d4848540d9de8e1ae4a01a467,
>>> which is different to f29f80c194d0c534a92354b2bc19022a9b70ecf8 on
>>> master.
>>
>> I've worked out at least when these two werid commits turned up on
>> core-updates.
>>
>> 12b15585a7 is mentioned here:
>>   https://lists.gnu.org/archive/html/guix-commits/2023-09/msg00955.html
>>
>> and 28d1413095 is mentioned here:
>>   https://lists.gnu.org/archive/html/guix-commits/2024-03/msg00381.html
>>
>>
>> With the changes last month in March, I was going to suggest deleting
>> the branch and then re-creating from f205179ed2 and trying to re-apply
>> the changes that should be on core-updates, while avoiding any
>> "duplicate" commits. However, I'm not even sure where to being with the
>> ~5000 commits pushed in September, at least one of them is a duplicate
>> of a commit on master, but I'm not sure how many of the other ~5000 are.
>>
>> For comparison, I did a merge of master in to core-updates today, and
>> this is what it shows up like on guix-commits:
>>
>>   https://lists.gnu.org/archive/html/guix-commits/2024-04/msg01209.html
>>
>> There are only two new revisions, the ed update I pushed, and the merge
>> commit, which is what a merge should look like as far as I'm aware.
>
> I think probably what happened is that in the middle of a merge of
> master -> core-updates (which entails sometimes painful conflicts
> resolution), a new commit pushed to core-updates, and to be able to push
> the resulting local branch (including the thousands of commits from the
> merge commit) got rebased on the remote core-updates.
>
> Perhaps another merge commit appeared on the remote around the same
> time, which would explain the duplicates.
>
> While I agree it's messy to have 5000 of duplicated commits, I'm not
> sure attempting to rewrite the branch, which has seen a lot of original
> commits, is a good idea (it'd be easy to have some good commits fall
> into cracks, leading to lost of work).

I think it's important to weigh up the cost and risks associated with
either merging these commits, or somehow avoiding doing so. I think the
potential impact is more than just a bit of messy Git history.

Assuming we merge core-updates without doing anything about these
duplicate commits, and taking the cwltool package as a semi-random
example, if you do:

  git log -p gnu/packages/bioinformatics.scm

You're going to see two commits for the update to 3.1.20240112164112,
that's maybe confusing, but not a big issue I guess since they look the
same, just different hashes.

But say you're looking at the Git history because you want that specific
version of cwltool and you're going to use guix time-machine or an
inferior looking at that revision. Well, it's a lucky dip. If you pick
the original master commit, you're in luck, you'll probably get
substitutes for cwltool. But if you pick the other seemingly identical
commit, you're effectively checking out core-updates as it was last
month and the chance of substitutes is much less likely. I also can't
really think how you'd work out which commit is best to use once
core-updates is merged? The easiest way would probably be to check the
signature, but that will only work most of the time.

This isn't a new issue, it's already problematic for substitute
availability to use intermediate commits (commits that weren't directly
pointed to by master). But there are over 1000 packages who's versions
are being changed on core-updates currently, or at least it looks like
this because of the duplicate commits, and if I'm correct about how
people are using the git history to find commits for specific versions
of packages, then having these duplicates in the Git history for master
forever more is going to catch people out for as long as those versions
remain relevant.

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bug#70456: Request for merging "core-updates" branch

[Maxim Cournoyer]

Hi Christopher,

Christopher Baines <mail@cbaines.net> writes:

[...]

> Assuming we merge core-updates without doing anything about these
> duplicate commits, and taking the cwltool package as a semi-random
> example, if you do:
>
>   git log -p gnu/packages/bioinformatics.scm

I trust the 'newest' (appearing first in 'git log --grep='cwltool:
Update') would yield the commit having substitutes?

If so, the inconvenience is somewhat mitigated, as long as you know to
use the newest of duplicated commits.

-- 
Thanks,
Maxim

bug#70456: Request for merging "core-updates" branch

[tumashu]

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emacs has a script gitmerge.el, it can skip some commit when merge with different merge rule (ours), maybe can make life easier:


https://git.savannah.gnu.org/cgit/emacs.git/tree/admin/gitmerge.el


https://git.savannah.gnu.org/cgit/emacs.git/tree/admin/notes/git-workflow











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Re: bug#70456: Request for merging "core-updates" branch

[Ludovic Courtès]

Hi Chris and all,

Christopher Baines <mail@cbaines.net> skribis:

> I think keeping the Git commit history clean and representative is
> really important, so to me at least this means core-updates can't be
> merged to master in it's current form, even if the changes overall from
> these 6351 commits are reasonable.
>
> I'm really not sure how to move forward though, I had a go at trying to
> rebuild the branch without introducing the thousands of duplicate
> commits and that produced a branch with 765 commits over master, which
> still seems a lot, but a big improvement over 6351:
>
>   https://git.cbaines.net/guix/log/?h=chris-core-updates-no-duplicates-attempt
>
> That was really hard going though, as there's plenty of merge conflicts
> along the way, and I'm pretty sure I solved some of them
> incorrectly. The resulting branch also differs from core-updates.

Woow, impressive.  How did you go about finding which commits were
duplicates/cherry-picked from master?  Which commit did you start from?

Given everything you’ve explained, it seems to me it’s worth trying to
start from a clean branch like this.

I checked it out (commit da77ea23daa0bfa4a73290dff99b22d6825ff80b) to
get an idea of where we are and got this:

--8<---------------cut here---------------start------------->8---
make[2]: *** No rule to make target 'gnu/packages/patches/glib-networking-gnutls-binding.patch', needed by 'all-am'.
make[2]: *** No rule to make target 'gnu/packages/patches/librecad-support-for-boost-1.76.patch', needed by 'all-am'.
--8<---------------cut here---------------end--------------->8---

It stopped at:

--8<---------------cut here---------------start------------->8---
gnu/packages/sdl.scm:72:2: error: (package (name "sdl2") (version "2.30.1") (source (origin (method url-fetch) (uri (string-append "https://libsdl.org/release/SDL2-" version ".tar.gz")) (sha256 (base32 "0fj7gxc7rlzzrafnx9nmf7ws3paxy583fmx7bcbavi6gr3xmy881")))) (arguments (list #:tests? #f #:configure-flags (gexp (append (quote ("--disable-wayland-shared" "--enable-video-kmsdrm" "--disable-kmsdrm-shared")) (quote ("--disable-alsa-shared" "--disable-pulseaudio-shared" "--disable-x11-shared" "LDFLAGS=-lGL")))) #:make-flags (gexp (cons* (string-append "LDFLAGS=-Wl,-rpath," (ungexp (this-package-input "eudev")) "/lib" ",-rpath," (ungexp (this-package-input "vulkan-loader")) "/lib") (quote ("V=1")))))) (propagated-inputs (list libx11 libcap mesa)) (native-inputs (list pkg-config)) (inputs (list libxrandr glu alsa-lib pulseaudio dbus eudev glib ibus-minimal libxkbcommon libxcursor vulkan-loader wayland wayland-protocols)) (outputs (quote ("out" "debug"))) (synopsis "Cross platform game development library") (description "Simple DirectMedia Layer is a cross-platform development library designed to\nprovide low level access to audio, keyboard, mouse, joystick, and graphics\nhardware.") (home-page "https://libsdl.org/") (license license:bsd-3)): missing field initializers (build-system)
--8<---------------cut here---------------end--------------->8---

I guess these are merge conflicts that weren’t correctly resolved.

This branch rewrites the entire ‘core-updates’ history.  What about
rewriting starting from the first series of “duplicate” commits?  That
should solve the immediate issue while keeping the “known good” history?

Thanks,
Ludo’.

bug#70456: Process gnome-team before core-updates

[Christopher Baines]

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block 70456 by 70766
thanks

I think being able to merge core-updates is still a few weeks away, so I
think there's time to build and merge gnome-team without delaying
core-updates.

If it does become a problem, we can always switch approach and wait
until after core-updates is merged to look at gnome-team.

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