From: Matthew Cengia <hidden> Date: 2016-06-15 22:59:17
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The other day I was merging a feature branch (shown below as
origin/22869-new-kernel) into my staging release (shown below as 'wtf'),
and it *reverted* a bucket-load of changes I'd made on other branches
which had been merged into staging before. I can't for the life of me
work out why this happened, and would appreciate any ideas. Output below
shows symptoms:
mattcen@sonar:prisonpc(wtf)$ git log --numstat --oneline origin/22869-new-kernel ^wtf | cat
a8879c2 Oops, name .config consistently with deb.
2797 0 client/kernel/config-3.5.7.20-1
0 2797 client/kernel/config-3.5.7.21-1
4c34686 Further lock down the inmate kernel.
366 1094 client/kernel/config-3.5.7.21-1
- - client/kernel/linux-firmware-image_3.5.7.21-1_i386.deb
- - client/kernel/linux-image-3.5.7.20_3.5.7.20-1_i386.deb
- - client/kernel/linux-image-3.5.7.21_3.5.7.21-1_i386.deb
6 7 client/scm/50-kernel-prisoner.scm
4a8acd0 Add build notes about how we generated these kernels.
37 0 client/kernel/README
e96adfe Merge remote-tracking branch 'origin/NNNNN-multicast-kernel' into 22869-new-kernel
4b8afeb Merge commit '8ef01f2' into 22869-new-kernel
fc4a5e6 Allow staff machines to receive IPTV stuff (per russm).
1 0 client/scm/50-staff.scm
117e646 Merge remote branch 'origin/staging' into NNNNN-multicast-kernel
deb3b38 allow IGMP reports out through iptables
1 0 client/scm/20-security.scm
8ef01f2 Enable multicast in inmate kernel.
0 3034 client/kernel/config-2.6.32.46+drm33.20
3036 0 client/kernel/config-2.6.32.61+drm33.26
- - client/kernel/linux-firmware-image_2.6.32.46+drm33.20-1_all.deb
- - client/kernel/linux-firmware-image_2.6.32.61+drm33.26-1_all.deb
- - client/kernel/linux-image-2.6.32.46+drm33.20_2.6.32.46+drm33.20-1_i386.deb
- - client/kernel/linux-image-2.6.32.61+drm33.26_2.6.32.61+drm33.26-1_i386.deb
11 11 client/scm/50-prisoner.scm
mattcen@sonar:prisonpc(wtf)$ git merge origin/22869-new-kernel
Auto-merging tca/parts.d/pxelinux-cfg
Auto-merging pre-install.sh
Removing ppcadm/templates/wwwfilter.tpl
Removing ppcadm/templates/streaming_media.tpl
Removing ppcadm/templates/disc_summary.tpl
Removing ppcadm/templates/disc_access.tpl
Auto-merging ppcadm/modules/quarantine.py
CONFLICT (content): Merge conflict in ppcadm/modules/quarantine.py
Auto-merging ppcadm/modules/media.py
CONFLICT (content): Merge conflict in ppcadm/modules/media.py
CONFLICT (modify/delete): ppcadm/modules/emailstats.py deleted in origin/22869-new-kernel and modified in HEAD. Version HEAD of ppcadm/modules/emailstats.py left in tree.
Removing generate-mail-stats
Removing doc/adminguide/images/streaming_media-screen.png
Auto-merging debian/rules
Auto-merging debian/prisonpc-internet.install
CONFLICT (content): Merge conflict in debian/prisonpc-internet.install
Auto-merging debian/prisonpc-core.cron.d
Auto-merging debian/NEWS
CONFLICT (content): Merge conflict in debian/NEWS
Auto-merging client/scm/50-kernel-prisoner.scm
CONFLICT (content): Merge conflict in client/scm/50-kernel-prisoner.scm
Removing client/kernel/linux-image-3.5.7.21_3.5.7.21-1_i386.deb
Removing client/kernel/linux-firmware-image_3.5.7.21-1_i386.deb
Auto-merging client/kernel/config-3.5.7.20-1
Resolved 'client/scm/50-kernel-prisoner.scm' using previous resolution.
Resolved 'debian/NEWS' using previous resolution.
Resolved 'debian/prisonpc-internet.install' using previous resolution.
Resolved 'ppcadm/modules/media.py' using previous resolution.
Resolved 'ppcadm/modules/quarantine.py' using previous resolution.
Automatic merge failed; fix conflicts and then commit the result.
mattcen@sonar:prisonpc(wtf)$ git status --porcelain
M client/kernel/README
R client/kernel/config-3.5.7.21-1 -> client/kernel/config-3.5.7.20-1
D client/kernel/linux-firmware-image_3.5.7.21-1_i386.deb
A client/kernel/linux-image-3.5.7.20_3.5.7.20-1_i386.deb
D client/kernel/linux-image-3.5.7.21_3.5.7.21-1_i386.deb
M client/scm/20-security.scm
M client/scm/30-apps.scm
UU client/scm/50-kernel-prisoner.scm
M client/scm/50-staff.scm
UU debian/NEWS
M debian/changelog
M debian/prisonpc-core.cron.d
UU debian/prisonpc-internet.install
M debian/rules
A doc/adminguide/images/streaming_media-screen.jpg
D doc/adminguide/images/streaming_media-screen.png
M doc/adminguide/images/web_filtering.png
M doc/adminguide/streaming_media.rst
M doc/adminguide/system-status.rst
M doc/adminguide/web_filtering.rst
M dovecot/dovecot-staff.conf
M eric/apps/complain.py
M eric/apps/links.py
M eric/apps/media.py
M eric/apps/whitelist.py
M eric/eric
M eric/eric_cfg.py
D generate-mail-stats
M ppcadm/modules/disc_access.py
UD ppcadm/modules/emailstats.py
UU ppcadm/modules/media.py
UU ppcadm/modules/quarantine.py
M ppcadm/modules/wwwfilter.py
M ppcadm/resources/admin.css
D ppcadm/templates/disc_access.tpl
D ppcadm/templates/disc_summary.tpl
M ppcadm/templates/home.tpl
D ppcadm/templates/streaming_media.tpl
M ppcadm/templates/user.tpl
D ppcadm/templates/wwwfilter.tpl
M pre-install.sh
M tca/parts.d/pxelinux-cfg
?? old/
?? paste
mattcen@sonar:prisonpc(wtf)$
- --
Regards,
Matthew Cengia
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From: Johannes Sixt <hidden> Date: 2016-06-15 22:59:17
Am 11/20/2013 4:49, schrieb Matthew Cengia:
The other day I was merging a feature branch (shown below as
origin/22869-new-kernel) into my staging release (shown below as 'wtf'),
and it *reverted* a bucket-load of changes I'd made on other branches
which had been merged into staging before. I can't for the life of me
work out why this happened, and would appreciate any ideas. Output below
shows symptoms:
Not really. It's impossible to tell what's wrong if you
- show only ..topic
- but not topic..
- and you keep secret which of the changes is unexpected.
Perhaps you did the following:
- On one branch, you made a change A and then another change B that reverts A.
- On the other branch, you also made the same changes as A, but there is
no equivalent of B.
In this case, it is expected that the changes made by B (i.e. the reversal
of change A) are *NOT* in the merge, i.e., the changes of A survive. It
looks as if the merge reverted change B.
If that is not the case, it could be helpful that you pick one of the
files that contains an unexpected change and post the output of
git log --left-right --oneline wtf...origin/22869-new-kernel \
file/with/changes | cut -c1-70
-- Hannes
From: Matthew Cengia <hidden> Date: 2016-06-15 22:59:17
On 2013-11-20 08:20, Johannes Sixt wrote:
[...]
Not really. It's impossible to tell what's wrong if you
Hi Hannes,
Thanks for your response, and sorry for providing insufficient
information; this is a company Git repo (it's also about 200MB), so I've
got be careful what I post, but I can certainly give more than I've
shown already.
Perhaps you did the following:
- On one branch, you made a change A and then another change B that reverts A.
- On the other branch, you also made the same changes as A, but there is
no equivalent of B.
In this case, it is expected that the changes made by B (i.e. the reversal
of change A) are *NOT* in the merge, i.e., the changes of A survive. It
looks as if the merge reverted change B.
I have found no evidence that this happened, but am not confident enough
to rule it out.
If that is not the case, it could be helpful that you pick one of the
files that contains an unexpected change and post the output of
git log --left-right --oneline wtf...origin/22869-new-kernel \
file/with/changes | cut -c1-70
Sure. I don't expect the merge to cause any changes to quarantine.py:
mattcen@sonar:prisonpc(wtf)$ git log --left-right --oneline \
wtf...origin/22869-new-kernel ppcadm/modules/quarantine.py | cut -c1-70
< 5b5f552 Fixed msg vs msg.as_string because smtp.sendmail is picky
< 03618f2 Use Return-Path, not X-Original-Envelope-From.
< dc1169e Bug squashing.
< 8e20216 Changed quarantine module to run maybe and send directly to
< d79ad42 Change final port, name the magic number.
< e44d1b3 Merge remote-tracking branch 'origin/staging' into 22912-ppc
< a03db6d Modified quarantine UI to handle the new reports format
Further, there are other files that don't change at all on either side
of the symetric diff:
mattcen@sonar:prisonpc(wtf)$ git log -M -C --left-right --oneline \
wtf...origin/22869-new-kernel generate-mail-stats | cut -c1-70
<no output>
I'm truly stumped. It's also worth noting that I've gone through and
manually resolved this merge one file at a time, and I'm about 90% sure
I ended up with the correct result, but it'd be nice to have had the
merge do the right thing in the first place, and I obviously want to
avoid having to do this again in a few months' time.
--
Regards,
Matthew Cengia
mattcen@sonar:prisonpc(wtf)$ git log --left-right --oneline \
wtf...origin/22869-new-kernel ppcadm/modules/quarantine.py | cut
-c1-70 < 5b5f552 Fixed msg vs msg.as_string because smtp.sendmail is
picky < 03618f2 Use Return-Path, not X-Original-Envelope-From. <
dc1169e Bug squashing. < 8e20216 Changed quarantine module to run
maybe and send directly to < d79ad42 Change final port, name the
magic number. < e44d1b3 Merge remote-tracking branch 'origin/staging'
into 22912-ppc < a03db6d Modified quarantine UI to handle the new
reports format
So, ppcadm/modules/quarantine.py changed only on our side, but not on
their side. This is in accordance with your listing above. Nevertheless,
the file is marked conflicted in your git status --porcelain output in
the original post:
UU ppcadm/modules/quarantine.py
That's strange. I can't tell what is going on. Perhaps you have some
criss-cross merges in your history that merge-recursive trips over?
Sorry, I don't know how to help you further.
-- Hannes
From: Jakub Narębski <hidden> Date: 2016-06-15 22:59:17
W dniu 2013-11-20 13:03, Matthew Cengia pisze:
On 2013-11-20 08:20, Johannes Sixt wrote:
[...]
quoted
Not really. It's impossible to tell what's wrong if you
Hi Hannes,
Thanks for your response, and sorry for providing insufficient
information; this is a company Git repo (it's also about 200MB), so I've
got be careful what I post, but I can certainly give more than I've
shown already.
I think there is some anonymizing tool for git, which replaces data
(blobs contents and file names) with artificial names, while preserving
history. It was intended to help debug repos with proprietary data...
but unfortunately I have not bookmarked it (or lost bookmark).
[...]
I'm truly stumped. It's also worth noting that I've gone through and
manually resolved this merge one file at a time, and I'm about 90% sure
I ended up with the correct result, but it'd be nice to have had the
merge do the right thing in the first place, and I obviously want to
avoid having to do this again in a few months' time.
Well, there is git-rerere (reuse recorded resolutions) which records
file-level (textual) merge resolutions and tries to reapply if
appropriate when merging.
Perhaps git-imerge tool would be of help in complicated merges?
--
Jakub Narębski
From: Matthew Cengia <hidden> Date: 2016-06-15 22:59:17
On 2013-11-20 13:29, Johannes Sixt wrote:
[...]
UU ppcadm/modules/quarantine.py
That's strange. I can't tell what is going on. Perhaps you have some
criss-cross merges in your history that merge-recursive trips over?
Sorry, I don't know how to help you further.
Hah! I worked it out!
$coworker erroneously did a "git merge -s ours" into the branch I was
merging in, and it undid more changes than he intended, which is what
resulted in *everything* breaking for me.
I've appropriately chastised him and most importantly understand why the
problem occured, which puts my mind at ease.
Thanks again for all your help.
--
Regards,
Matthew Cengia