[Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Randall S. Becker]

Another situation came up during regression testing on NonStop:

t5401 broke on the first run through (most tests), with the failures below. 

*** t5401-update-hooks.sh ***
not ok 1 - setup
#
#               echo This is a test. >a &&
#               git update-index --add a &&
#               tree0=$(git write-tree) &&
#               commit0=$(echo setup | git commit-tree $tree0) &&
#               echo We hope it works. >a &&
#               git update-index a &&
#               tree1=$(git write-tree) &&
#               commit1=$(echo modify | git commit-tree $tree1 -p $commit0)
&&
#               git update-ref refs/heads/master $commit0 &&
#               git update-ref refs/heads/tofail $commit1 &&
#               git clone --bare ./. victim.git &&
#               GIT_DIR=victim.git git update-ref refs/heads/tofail $commit1
&&
#               git update-ref refs/heads/master $commit1 &&
#               git update-ref refs/heads/tofail $commit0
#
t5401-update-hooks.sh: line 26: victim.git/hooks/pre-receive: No such file
or di
rectory
chmod: cannot access 'victim.git/hooks/pre-receive': No such file or
directory
t5401-update-hooks.sh: line 35: victim.git/hooks/update: No such file or
directo
ry
chmod: cannot access 'victim.git/hooks/update': No such file or directory
t5401-update-hooks.sh: line 45: victim.git/hooks/post-receive: No such file
or d
irectory
chmod: cannot access 'victim.git/hooks/post-receive': No such file or
directory
t5401-update-hooks.sh: line 54: victim.git/hooks/post-update: No such file
or di
rectory
chmod: cannot access 'victim.git/hooks/post-update': No such file or
directory
ok 2 - push
etc.

When running the test in isolation, it passes without incident whether or
not --verbose is used. So far, this only occurs on the first run through. I
wanted to report it, based on the inconsistency of results. This is not the
first time tests have acted in this fashion, and I realize it is difficult
to do anything about it without being able to recreate the situation.

Such as it is,
Randall

Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[brian m. carlson]

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On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> When running the test in isolation, it passes without incident whether or
> not --verbose is used. So far, this only occurs on the first run through. I
> wanted to report it, based on the inconsistency of results. This is not the
> first time tests have acted in this fashion, and I realize it is difficult
> to do anything about it without being able to recreate the situation.

Does running git clean -dxf cause it to be reproducible?
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204

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RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Randall S. Becker]

On May 21, 2019 20:48, brian m. carlson wrote:
> To: Randall S. Becker <rsbecker@nexbridge.com>
> Cc: 'Git Mailing List' <git@vger.kernel.org>
> Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> 
> On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > When running the test in isolation, it passes without incident whether
> > or not --verbose is used. So far, this only occurs on the first run
> > through. I wanted to report it, based on the inconsistency of results.
> > This is not the first time tests have acted in this fashion, and I
> > realize it is difficult to do anything about it without being able to recreate
> the situation.
> 
> Does running git clean -dxf cause it to be reproducible?

I will give it a go. Having exactly the same behaviour in t7519 subtest 19. I wonder whether there are breadcrumbs not being cleaned up. Will report back when I am able - may take a day or so.

Cheers,
Randall

Issues with t7519.19, was RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Johannes Schindelin]

Hi Randall,

On Wed, 22 May 2019, Randall S. Becker wrote:

> On May 21, 2019 20:48, brian m. carlson wrote:
> > To: Randall S. Becker <rsbecker@nexbridge.com>
> > Cc: 'Git Mailing List' <git@vger.kernel.org>
> > Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> >
> > On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > > When running the test in isolation, it passes without incident
> > > whether or not --verbose is used. So far, this only occurs on the
> > > first run through. I wanted to report it, based on the inconsistency
> > > of results. This is not the first time tests have acted in this
> > > fashion, and I realize it is difficult to do anything about it
> > > without being able to recreate
> > the situation.
> >
> > Does running git clean -dxf cause it to be reproducible?
>
> I will give it a go. Having exactly the same behaviour in t7519 subtest
> 19. I wonder whether there are breadcrumbs not being cleaned up. Will
> report back when I am able - may take a day or so.

I fear that t7519's problems are *completely* unrelated to the t5401 issue
you reported earlier. I hunted the t7519 problems down today, and I could
imagine that these patches fix your t7519, too:

	https://github.com/gitgitgadget/git/pull/223

Ciao,
Johannes

RE: Issues with t7519.19, was RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Randall S. Becker]

On May 23, 2019 16:06, Johannes Schindelin wrote:
> On Wed, 22 May 2019, Randall S. Becker wrote:
> 
> > On May 21, 2019 20:48, brian m. carlson wrote:
> > > To: Randall S. Becker <rsbecker@nexbridge.com>
> > > Cc: 'Git Mailing List' <git@vger.kernel.org>
> > > Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> > >
> > > On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > > > When running the test in isolation, it passes without incident
> > > > whether or not --verbose is used. So far, this only occurs on the
> > > > first run through. I wanted to report it, based on the
> > > > inconsistency of results. This is not the first time tests have
> > > > acted in this fashion, and I realize it is difficult to do
> > > > anything about it without being able to recreate
> > > the situation.
> > >
> > > Does running git clean -dxf cause it to be reproducible?
> >
> > I will give it a go. Having exactly the same behaviour in t7519
> > subtest 19. I wonder whether there are breadcrumbs not being cleaned
> > up. Will report back when I am able - may take a day or so.
> 
> I fear that t7519's problems are *completely* unrelated to the t5401 issue
> you reported earlier. I hunted the t7519 problems down today, and I could
> imagine that these patches fix your t7519, too:
> 
> 	https://github.com/gitgitgadget/git/pull/223

From the description, I believe it. Timestamp resolution on NonStop is in microseconds and those are not even slightly simulated. Coupled with this being an MPP not SMP, things can occur within the same microsecond, or in weird situations slightly before or after when comparing the clock on different CPUs. Yes, time-travel is possible at the single microsecond level 😉. Cores are synchronized, but our machine has 4 CPUs and synchronizing the file system across all of them does lead to slightly strange situations.

RE: Issues with t7519.19, was RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Johannes Schindelin]

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Hi Randall,

On Thu, 23 May 2019, Randall S. Becker wrote:

> On May 23, 2019 16:06, Johannes Schindelin wrote:
> > On Wed, 22 May 2019, Randall S. Becker wrote:
> >
> > > On May 21, 2019 20:48, brian m. carlson wrote:
> > > > To: Randall S. Becker <rsbecker@nexbridge.com>
> > > > Cc: 'Git Mailing List' <git@vger.kernel.org>
> > > > Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> > > >
> > > > On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > > > > When running the test in isolation, it passes without incident
> > > > > whether or not --verbose is used. So far, this only occurs on the
> > > > > first run through. I wanted to report it, based on the
> > > > > inconsistency of results. This is not the first time tests have
> > > > > acted in this fashion, and I realize it is difficult to do
> > > > > anything about it without being able to recreate
> > > > the situation.
> > > >
> > > > Does running git clean -dxf cause it to be reproducible?
> > >
> > > I will give it a go. Having exactly the same behaviour in t7519
> > > subtest 19. I wonder whether there are breadcrumbs not being cleaned
> > > up. Will report back when I am able - may take a day or so.
> >
> > I fear that t7519's problems are *completely* unrelated to the t5401 issue
> > you reported earlier. I hunted the t7519 problems down today, and I could
> > imagine that these patches fix your t7519, too:
> >
> > 	https://github.com/gitgitgadget/git/pull/223
>
> From the description, I believe it. Timestamp resolution on NonStop is in microseconds and those are not even slightly simulated. Coupled with this being an MPP not SMP, things can occur within the same microsecond, or in weird situations slightly before or after when comparing the clock on different CPUs. Yes, time-travel is possible at the single microsecond level 😉. Cores are synchronized, but our machine has 4 CPUs and synchronizing the file system across all of them does lead to slightly strange situations.

I tested my patches with

	sh t7519-status-fsmonitor.sh --stress-jobs=8 --stress-limit=10

Why don't you check out my branch, build and test, and then we know
whether it fixes your t7519 bug?

Ciao,
Johannes

RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Randall S. Becker]

On May 21, 2019 20:48, brian m. carlson wrote:
> To: Randall S. Becker <rsbecker@nexbridge.com>
> Cc: 'Git Mailing List' <git@vger.kernel.org>
> Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> 
> On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > When running the test in isolation, it passes without incident whether
> > or not --verbose is used. So far, this only occurs on the first run
> > through. I wanted to report it, based on the inconsistency of results.
> > This is not the first time tests have acted in this fashion, and I
> > realize it is difficult to do anything about it without being able to recreate
> the situation.
> 
> Does running git clean -dxf cause it to be reproducible?

Made no difference. t5401 passed cleanly after a the clean -dxf. I don't know where the breadcrumbs are. I guess it could be something funky in the file system on platform or with bash.

RE: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh

[Johannes Schindelin]

Hi Randall,

On Thu, 23 May 2019, Randall S. Becker wrote:

> On May 21, 2019 20:48, brian m. carlson wrote:
> > To: Randall S. Becker <rsbecker@nexbridge.com>
> > Cc: 'Git Mailing List' <git@vger.kernel.org>
> > Subject: Re: [Breakage] 2.22.0-rc1 t5401-update-hooks.sh
> >
> > On 2019-05-21 at 21:47:54, Randall S. Becker wrote:
> > > When running the test in isolation, it passes without incident
> > > whether or not --verbose is used. So far, this only occurs on the
> > > first run through. I wanted to report it, based on the inconsistency
> > > of results. This is not the first time tests have acted in this
> > > fashion, and I realize it is difficult to do anything about it
> > > without being able to recreate
> > the situation.
> >
> > Does running git clean -dxf cause it to be reproducible?
>
> Made no difference. t5401 passed cleanly after a the clean -dxf. I don't
> know where the breadcrumbs are. I guess it could be something funky in
> the file system on platform or with bash.

FWIW I do not see any of the major platforms having any sort of regression
in t5401:
https://dev.azure.com/gitgitgadget/git/_test/analytics?definitionId=4&contextType=build

So I guess the only way you will find out more about this issue is by
instrumenting the code and digging in. You will most likely find that the
`--stress` mode will help you recreate the situation rather easily.

Ciao,
Johannes