pub fn diff_model(
migrations_dir: &Path,
table: &str,
model: &ModelSpec,
dialect: Dialect,
) -> Result<Option<SchemaDiff>>Expand description
Compute the diff for model (a module’s declared shape) against the columns already
present in its table’s generated migrations under migrations_dir.
Returns Ok(None) when the table does not exist after replay — there is nothing
to diff against, and the caller should scaffold the resource (make crud / sync) first.