# `Trellis.Divergence`
[🔗](https://github.com/salesforce-misc/trellis/blob/v0.1.0-alpha/clients/elixir/lib/trellis/self_check.ex#L137)

One thing `Trellis.self_check/3` found out of step, by `kind`:

- `:cell`: the row exists on both sides but `column` differs at `key`.
  `persisted` is the target table's value and `recomputed` the fresh
  recompute's, both as Postgres renders them as text (`nil` for `NULL`).
- `:missing_row`: the recompute produced `key`, but the target has no row
  for it.
- `:extra_row`: the target has a row for `key` that the recompute didn't
  produce.
- `:missing_column`: the definition expects `column`, but the target table
  doesn't have it.
- `:extra_column`: the target table has `column`, but the definition
  doesn't expect it.
- `:capture`: a table the target is computed from isn't being captured as
  Trellis installed it (a capture trigger missing, disabled or calling the
  wrong function, a capture function missing or with the wrong owner, the
  Trellis role missing a privilege, or the table joined a partition or
  inheritance hierarchy). `detail` says what, and `table` names the table
  (`nil` for a missing privilege). `Trellis.self_check/3` reports these
  before, and instead of, comparing any rows.

Fields a kind doesn't carry are `nil`.

# `kind`

```elixir
@type kind() ::
  :cell | :missing_row | :extra_row | :missing_column | :extra_column | :capture
```

What kind of divergence this is.

# `t`

```elixir
@type t() :: %Trellis.Divergence{
  column: String.t() | nil,
  detail: String.t() | nil,
  key: String.t() | nil,
  kind: kind(),
  persisted: String.t() | nil,
  recomputed: String.t() | nil,
  table: String.t() | nil
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*