Thanks Matt. Seems like there is interest in doing this. Separately, Sung has a similar proposal in the community and we are connected offline to sync and converge since the proposals are along similar lines. Will update this thread as we discuss. If there are more folks interested in this, it might be worth doing a community on-off sync to brainstorm this as well.
On Mon, Jun 29, 2026 at 8:30 AM Matt Topol <[email protected]> wrote: > Thanks for the proposal! I'm gonna read through this, but I just wanted to > chime in that this is something I've been desiring and hoping for for a > long time. We've encountered tons of cases during the development of > iceberg-go where implementations diverged while still following the letter > of the spec. This kind of testing is very much needed. > > --Matt > > On Mon, Jun 29, 2026, 11:11 AM Neelesh Salian <[email protected]> > wrote: > >> Hi all, >> >> Each Iceberg implementation has its own tests, but there isn't a shared >> way to check that >> a table written by one is read the same way by another. >> A few examples that have come up across the implementations: a manifest >> written by one client that another can't read, >> a metadata.json one writer produces that another rejects because they >> disagree on whether a field is required, and a partition transform that >> ends up encoded more than one way across implementations. Some of these >> turned out to be bugs, others places where the spec is ambiguous. >> >> We think this is worth solving with some form of shared >> cross-implementation conformance testing, and we'd like to align as a >> community on whether to take it on and how best to start. We've written up >> our current thinking, a possible direction, and a small prototype in the >> doc below. >> >> Details, a repo design, and the interop failures we've collected: >> https://docs.google.com/document/d/1HRcUMcrqUjo4CjGdwAIw85f7miWOGJ4ZJ90AgHbahaw/edit?usp=sharing >> >> >> Feedback welcome on whether this is worth doing and how we might get >> started. >> >> Thanks, >> Neelesh (with Andrei Tserakhau) >> >
