[OE-core] Overriding SDE_FILE

[Jacob Kroon]

On 2/27/20 11:35 PM, Douglas Royds via Openembedded-core wrote:
> On 28/02/20 11:34 am, Joshua Watt wrote:
> 
>>
>> On 2/27/20 4:29 PM, Douglas Royds wrote:
>>>
>>> On 28/02/20 10:49 am, Joshua Watt wrote:
>>>
>>>>
>>>> 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.
>>>>
>>> If it works, it's good. I like the fact that the user can just set 
>>> SOURCE_DATE_EPOCH directly in their recipe.
>>>
>>> How about ...
>>>
>>>     BB_HASHBASE_WHITELIST += "${@'SOURCE_DATE_EPOCH' if not
>>>     source_date_epoch_var(d) else ''}"
>>>
>> Ya, that works. The only reason I chose "is None" was in case a user 
>> really wanted to do
>>
>>   SOURCE_DATE_EPOCH = "0"
>>
> True, best to allow for that.
> 

Joshua, I just tried the two top patches in your reproducible branch; I 
can see that SOURCE_DATE_EPOCH is not in BB_HASHBASE_WHITELIST, however, 
changing its value in my recipe doesn't trigger rebuilding for some reason..