Re: [PATCH 5/7] commit-graph: document file format v2

> On Tue, Mar 01 2022, Derrick Stolee wrote:
> 
>> On 2/28/2022 4:14 PM, Ævar Arnfjörð Bjarmason wrote:
>>>
>>> On Mon, Feb 28 2022, Derrick Stolee wrote:
>>> I think arguable that's OK/worth it, but it's "not [any] issues", no?
>>
>> What I mean is that this change does not enable the new graph version
>> by default, so these users do not have any issues unless someone opts
>> in to the feature while in this mixed scenario.
> 
> Indeed. FWIW I wasn't confused about that bit. I'm just commenting on
> /how/ we do version upgrades, and if we can save users unnecessary
> hassle relatively easily.
> 
> But I also think the writing is on the wall that you'll want to
> (understandably) bump the default sooner than later, or if not for this
> data for other future chunks.

>> Finally, the end result becomes "older versions get slower without
>> any warning" instead of "older versions get a message about not
>> understanding the commit-graph file".
> 
> Sure, IF you want to write such an empty chunk. The point is that you
> now have the option.
> 
> And this is the same edge case we already dealt with for
> GDAT/GDOV. I.e. older readers who didn't understand it would be slower.
> 
> We can still have a feature to make older clients intentionally
> break/warn, it seems to me that if you'd want such a thing you'd want it
> aside from the specific mechanism of this proposed upgrade.
> 
> Or you could dual-write the data for older clients, which I think
> probably isn't worth the hassle.
> 
> I.e. if you're worried about silent slowdown older clients happily
> ignoring the BIDX and BDAT chunks are silently slower.