bulkio/import: bug when mixing existing and new tables?

[nvanbenschoten]

I was casually skimming over the code trying to understand #50731 and stumbled upon this block of code:

cockroach/pkg/ccl/importccl/import_stmt.go

Lines 1011 to 1023 in 8f768ad

	if len(newTableDescs) != 0 {
	res, err := prepareNewTableDescsForIngestion(ctx, txn, p, newTableDescs, importDetails.ParentID)
	if err != nil {
	return err
	}
	for i, table := range res {
	importDetails.Tables[i] = jobspb.ImportDetails_Table{Desc: table,
	Name: details.Tables[i].Name,
	SeqVal: details.Tables[i].SeqVal,
	IsNew: details.Tables[i].IsNew,
	TargetCols: details.Tables[i].TargetCols}
	}
	}

I couldn't make sense of it, and I now think it's a bug. Specifically, I think the indexing is wrong here, as it doesn't handle the case where len(newTableDescs) < len(importDetails.Tables) correctly. Looking up, we see an unused map newTableDescToIdx, which is exactly what we want here. So I think we're just forgetting to use this map. I think we want something like i := newTableDescToIdx[i] in the loop over res.

I don't know if this is actually possible to hit as a user, as I believe IMPORT only allows new tables and IMPORT INTO only allows existing tables.

[adityamaru]

Thanks for flagging, looking into it.