[Rpm-maint] RFC: RPMTAG_IDENTITY (whitelist filter)

[Panu Matilainen]

On 9/19/18 12:23 PM, Panu Matilainen wrote:
> On 8/23/18 12:01 AM, Vladimir D. Seleznev wrote:
>> You convinced me that there should be whitelist filter, so I rewrote
>> code for it. Follow Panu suggestion [1] I wrote .C generator to filter
>> proper rpm tags. 
> 
> Sorry for the terribly late response, I keep intending and intending and 
> somehow almost a month passed :(
> 
> Also shows that its a while since the initial discussion: I don't recall 
> suggesting that :D but nevermind.
> 
> Another possibility that wouldn't need a separate generator script would 
> be just including that info in the tag table itself, similarly to how 
> "extension" is there, although I think there's no API to access it ATM 
> (another idea that was never finished). Might as well make it a flags 
> bitfield where we can cram such stuff and rpmTagGetFlags() or so to 
> fetch the data...
> 
>> But currently it does not allow this suggestion [2] by
>> jbj@:
>>
>> "The members (and ordering) of the IDENTITY tag set might also
>> need to be configurable without recompiling."
>>
>> Currently I have no idea what is better way to do that. May be one of
>> solution can be to define some macro that contains tag that should be in
>> calculation, but this doest seem to be convenient and practical.
>>
>> Also its value may be needs a prefix for versioning tag value. When new
>> tags are marked to be involve to calculating the prefix changes. I think
>> the prefix should also include a vendor identifier e.g. fc, alt, mga,
>> suse etc.
> 
> I dunno why it should be vendor specific, we rather try to avoid such 
> things in the first place.
> 
>>
>> While here is marker for tags that values should be involve to identity
>> calculation, I think here should be special case for some of string
>> array tags: a marker for processing array before calculation. For
>> example, we want to filter some of value from package provides but we
>> don't want to exclude the whole array from identity calculation. I think
>> it could be done with one more marker with argument of array processing
>> function that return (char *) — the result of string processing. There
>> is difficulty that RPMTAG_PROVIDE* is three separate tags and I have no
>> idea how to take it in consideration.
> 
> Why do you want to filter provides?

Okay it was mentioned at least in here: 
https://github.com/rpm-software-management/rpm/issues/426 :

>> P.S. Since RPMTAG_RELEASE is supposed to be filtered, there is
>> sense to filter some elemenents of package RPMTAG_PROVIDE* and RPMTAG_REQUIRE*

I dont see how you could meaningfully filter RPMTAG_RELEASE, it can be 
(and often is) embedded in any number of places where you cannot 
possibly know whether it was originally hardcoded to that value or if it 
came from RPMTAG_RELEASE.

	- Panu -