Function do_materialize 

pub async fn do_materialize(
    _config: &Config,
    tables: &Arc<ArcSwap<TableRegistry>>,
    params: MaterializeParams,
) -> Result<MaterializeResult, MiniAppError>

Execute the row_materialize tool.

Selects rows from the target table, projects fields, serialises to the requested format, and writes the result to absolute filesystem path(s).

Crux constraints enforced here

1. Absolute path: params.dest is checked with Path::is_absolute() at step (a). Relative paths return MaterializeDestRelative immediately. No sandbox constraint is applied to absolute paths.
2. SHA-256: every MaterializeFile entry carries a 64-char hex SHA-256 digest, including when dry_run=true.

Arguments

• config — server mount configuration.
• tables — live ArcSwap-wrapped table registry.
• params — tool parameters.

Returns

MaterializeResult on success (JSON-serialisable).

Errors

• MiniAppError::MaterializeDestRelative — dest is not absolute.
• MiniAppError::MaterializeFieldUnknown — projected field not in schema.
• MiniAppError::MaterializeInvalidParam — incompatible parameter combination.
• MiniAppError::MaterializeRowNotFound — ById selector found no row.
• MiniAppError::MaterializeEmptyResult — ByFilter selector matched zero rows.
• MiniAppError::MaterializeFormatError — serialisation failure.
• MiniAppError::MaterializeDestInvalid — dest path problem or write_mode conflict.
• MiniAppError::MaterializeIo — filesystem write failure.
• MiniAppError::MaterializeSha256 — spawn_blocking task panic during SHA-256/write.