[OE-core] Overriding SDE_FILE

[Joshua Watt]

On 2/27/20 3:22 PM, Douglas Royds wrote:
>
> On 28/02/20 5:45 am, Joshua Watt wrote:
>
>> On 2/27/20 9:01 AM, Joshua Watt wrote:
>>> On 2/26/20 11:46 PM, Douglas Royds wrote:
>>>>
>>>> On 26/02/20 4:53 am, Jacob Kroon wrote:
>>>>
>>>>> On 2/24/20 8:25 AM, Jacob Kroon wrote:
>>>>>> Hi Douglas,
>>>>>>
>>>>>> You updated a comment in reproducible_build.bbclass, commit 
>>>>>> e7b891b76954c784f5a93bd0a1c91315673ce40d:
>>>>>>
>>>>>>> -# Once the value of SOURCE_DATE_EPOCH is determined, it is 
>>>>>>> stored in the recipe's ${SDE_FILE}.
>>>>>>> +# Once the value of SOURCE_DATE_EPOCH is determined, it is 
>>>>>>> stored in the recipe's SDE_FILE.
>>>>>>> +# If none of these mechanisms are suitable, replace the 
>>>>>>> do_deploy_source_date_epoch task
>>>>>>> +# with recipe-specific functionality to write the appropriate 
>>>>>>> SOURCE_DATE_EPOCH into the SDE_FILE.
>>>>>>> +#
>>>>>>
>>>>>> But I can't really get this to work. What did work for me was to 
>>>>>> replace "do_create_source_date_epoch_stamp()" in my recipe:
>>>>>>
>>>>>> do_create_source_date_epoch_stamp() {
>>>>>>      mkdir -p ${SDE_DIR}
>>>>>>      date -d "1981-03-03" "+%s" > ${SDE_FILE}
>>>>>> }
>>>>>>
>>>>>> What is the intended way to achieve the thing I'm trying to do 
>>>>>> here ?
>>>>>>
>>>>>
>>>>> FYI, JPEW has a proposed patch here
>>>>>
>>>>> http://git.yoctoproject.org/cgit.cgi/poky-contrib/commit/?h=jpew/reproducible&id=d091d2aa53ea417f70c10f5ce89151820c3db9ce 
>>>>>
>>>>>
>>>>> for allowing a recipe to just set SOURCE_DATE_EPOCH directly.
>>>>>
>>>>> But maybe that currently is at odds with SOURCE_DATE_EPOCH being 
>>>>> in BB_HASHBASE_WHITELIST ?
>>>>>
>>>>> /Jacob
>>>>
>>>>
>>>> On the surface of it, my comment appears to be just wrong: It does 
>>>> make sense to replace do_create_source_date_epoch_stamp() as you 
>>>> suggest.
>>>>
>>>> Joshua's proposed patch looks promising:
>>>>
>>>>   * Should the new function not be called first, so that it takes
>>>>     priority over the git, known files, and youngest file
>>>>     functions? If someone has explicitly set SOURCE_DATE_EPOCH,
>>>>     then they want it to take priority.
>>>>
>>> Having that be the first option makes sense. The only case in which 
>>> that might not work, is if a recipe does something like:
>>>
>>>  SOURCE_DATE_EPOCH = "${@my_awesome_sde_calculation(d)}"
>>>
>>> e.g. uses a function to get the SDE instead of setting to a fixed 
>>> value, but that's probably going to be extremely rare.
>>>
>>>
>>>>  *
>>>>
>>>>
>>>>
>>>>   * As you observe, SOURCE_DATE_EPOCH would need to be removed from
>>>>     BB_HASHBASE_WHITELIST. I'm not sure why it was in the whitelist
>>>>     in the first place.
>>>>
>>> I'm not sure why exactly it is whitelisted; I didn't write the 
>>> original code that whitelisted it, but I've CC'd Juro in case he 
>>> happens to remember.
>>>
>> After a discussion with Richard, we figured out why SOURCE_DATE_EPOCH 
>> has to be whitelisted. The value of the variable *must* be calculable 
>> at parse time before any task is ran, but in practice it's value is 
>> only available once the __source_date_epoch.txt file is present, 
>> which is after parsing. This causes the taskhash to be calculated 
>> differently during parsing and task execution which causes taskhash 
>> mismatch errors.
>>
>
> True.
>
> What to do? Would it work to use a different non-whitelisted variable 
> in the recipe, eg. SOURCE_DATE_EPOCH_FIXED?
>

Ya, that would work. You'd have to figure out how to get the variable to 
be included in each taskhash even though it's not directly referenced, 
but I'm sure that's possible.


Another option that's at lot more "magic" would be something like this: 
http://git.yoctoproject.org/cgit.cgi/poky-contrib/commit/?h=jpew/reproducible&id=2b524916cf35238ff3deea34017e8a4cd73926cd 


That's really weird, and I'm not sure I like it, but worth a thought.


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