[OE-core] uninative and recipe parsing

[Cuero Bugot]

> I have kind of noticed this and agree its something we should fix.
> Thanks for digging into it. I think a long time ago we tried the above change and it does cause a problem, perhaps fetching during parsing which is bad.
>
> Have you been able to figure out what changes in the data store for the cache to be invalidated? I think whitelisting something may be the best solution, or perhaps only activating certain changes in the build code > paths after parsing in all cases.
>

Yes absolutely the variables and content diff is as follow:
830c830
< ('NATIVELSBSTRING', 'neon-16.04')
---
> ('NATIVELSBSTRING', 'universal')
1447c1447,1449
< ('SSTATEPOSTUNPACKFUNCS', 'sstate_hardcode_path_unpack')
---
> ('SSTATEPOSTUNPACKFUNCS', 'sstate_hardcode_path_unpack uninative_changeinterp')
> ('SSTATEPOSTUNPACKFUNCS[_append]', [[' uninative_changeinterp', None]])
> ('SSTATEPOSTUNPACKFUNCS[vardepvalueexclude]', '| uninative_changeinterp')

I did a PR (PATCH) for the 1st alternative (fetching earlier) here: https://patchwork.openembedded.org/series/11369/
But I need to do a v2 to fix the short description to make shorter. if you ever decided that it could be way to go. (FWIW I did test it on our setup and yes it is fetching the uninative binaries early on or maybe during the parsing, see output bellow):

	cbugot at neon:~/devs/yocto/build$ bitbake some-image
	--2018-03-13 18:25:36--  http://build-cache-server/cache//downloads/x86_64-nativesdk-libc.tar.bz2                                                                                                                                                                         
	Resolving build-cache-server (build-cache-server)... 10.41.51.220                                                                                                                                                                                                              
	Connecting to build-cache-server (build-cache-server)|10.41.51.220|:80... connected.                                                                                                                                                                                           
	HTTP request sent, awaiting response... 200 OK                                                                                                                                                                                                                                 
	Length: 2286285 (2.2M) [application/x-bzip2]                                                                                                                                                                                                                                   
	Saving to: ‘/home/cbugot/devs/unity/build/downloads/uninative/ed033c868b87852b07957a4400f3b744c00aef5d6470346ea1a59b6d3e03075e/x86_64-nativesdk-libc.tar.bz2’                                                                                                                                                                                                                                                                                                                        
	2018-03-13 18:25:36 (11.2 MB/s) - ‘/home/cbugot/devs/unity/build/downloads/uninative/ed033c868b87852b07957a4400f3b744c00aef5d6470346ea1a59b6d3e03075e/x86_64-nativesdk-libc.tar.bz2’ saved [2286285/2286285]                                                                                                                                                                                                                                                                                                                               
	NOTE: Fetching uninative binary shim from http://downloads.yoctoproject.org/releases/uninative/1.7/x86_64-nativesdk-libc.tar.bz2;sha256sum=ed033c868b87852b07957a4400f3b744c00aef5d6470346ea1a59b6d3e03075e                                                                    
	Parsing recipes:  37% |#######################################################################################                                                                                                                                                  | ETA:  0:06:30



However, if you think putting the two variables (NATIVELSBSTRING, SSTATEPOSTUNPACKFUNCS)  in BB_HASHCONFIG_WHITELIST is better/safer, I can also submit a PATCH request for that alternative.

Personally I do not have enough yocto experience to decide which one would be the best (just inferred that WHITELIST could lead to weird behavior if someone ever depended on one of this variable in his recipe); so I would be happy either way 😊.

Cheers,
Cuero