[Vm-dev] VM git commit hash (was: Image crashing on startup, apparently during GC)

[Alistair Grant]

Hi Ben,


On 2 April 2018 at 15:42, Ben Coman <btc at openinworld.com> wrote:
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>
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> On 2 April 2018 at 20:26, Alistair Grant <akgrant0710 at gmail.com> wrote:
>>
>>
>> On Sun, Apr 01, 2018 at 10:46:14AM -0700, Eliot Miranda wrote:
>> > Hi Alistair,
>> >
>> > _,,,^..^,,,_ (phone)
>> >
>> > > On Mar 31, 2018, at 1:42 PM, Alistair Grant <akgrant0710 at gmail.com> wrote:
>> > >
>> > > git doesn't provide a substitution mechanism like sccs, but the script
>> > > we have that embeds the date can just as easily embed the hash.  In
>> > > .git_filters/RevDateURL.smudge there's a line that retrieves the
>> > > commit date from git:
>> > >
>> > > $date = `git log --format=%ad -1`;
>> > >
>> > > to get the (short) hash we can simply add:
>> > >
>> > > $shorthash = `git log --format=%h -1`;
>> > >
>> > > The string substitution can then proceed as for the date.
>> > >
>> > > I think it would be worthwhile having both the date and hash in the
>> > > --version info.
>> > >
>> > > I'm happy to add this in and update the --version output if there's
>> > > general agreement.
>> >
>> > Yes please!!! The conventional alternative is to invoke git log from
>> > the makefiles and lass in the commit hash as a compiler-line default
>> > me.  But this is messy and slows down compilation (unless there is a
>> > special rule for just one file, and that's fragile).  I much prefer
>> > having the commit somewhere in source.
>>
>> Done:
>>
>> $ git log --oneline | head
>> 5a5b1c7 vm version string: add commit short hash
>> 4c4686e Skip SUnit testing in Sista builds
>> 79c0809 Merge pull request #230 from smalltalking/Cog
>> 804ed5c Fixed typo in the download URL
>>
>>
>> $ products/cogspur64linuxht/pharo --version
>> 5.0-201804012008-version_hash  Sun Apr  1 22:15:07 CEST 2018 gcc 5.4.0 [Production Spur 64-bit VM]
>> CoInterpreter VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr  1 2018
>> StackToRegisterMappingCogit VMMaker.oscog-eem.2361 uuid: 7ca2f89a-de70-422f-b92b-54f91ac4e47b Apr  1 2018
>> VM: 201804012008-version_hash alistair at 4c0a4b2bdb79:vmmaker/opensmalltalk-vm $
>> Date: Sun Apr 1 22:08:11 2018 +0200 $ Hash: 5a5b1c7 $
>
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> Maybe rather than just "Hash:" could it be more explicit as "GitHash:" or even "GitSHA1:"
> One day the algorithm is likely to change... "Moving Git past SHA-1" (https://lwn.net/Articles/715716/)
> and it may be useful later to be able to distinguish.

I like "GitHash" as it may not be obvious what the hash refers to for
a newcomer.  Even if/when git moves away from sha1, from a cli/ui
perspective presumably it will still just be "the hash".



>> Plugins: 201804012008-version_hash alistair at 4c0a4b2bdb79:vmmaker/opensmalltalk-vm $
>> Linux 4c0a4b2bdb79 4.13.0-37-generic #42~16.04.1-Ubuntu SMP Wed Mar 7 16:03:28 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
>> plugin path: products/cogspur64linuxht/lib/pharo/5.0-201804012008-version_hash [default: /home/alistair/vmmaker/opensmalltalk-vm/products/cogspur64linuxht/lib/pharo/5.0-201804012008-version_hash/]
>>
>>
>> As expected, the hash is also included in:
>>
>> - the VirtualMachine object (in Pharo, and the equivalent in squeak)
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> I presume this is what shows up under System > System Reporter ?

Yes.


>> - crash.dmp
>> - kill -USR1 output
>>
>>
>> https://github.com/OpenSmalltalk/opensmalltalk-vm/pull/233
>> if anyone wants to take a look.
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>
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> An interesting insight for me into how the version info is generated. thx.

Glad it was useful. :-)

Thanks for your feedback.  I'll update the PR (probably tomorrow).

Cheers,
Alistair