Changelog - 2026-10-10

The data provider throws an ApplicationError and reads Content-Range

Behavior Change Breaking Change

In one line. On a non-2xx response DefaultRestDataProvider, CountRestDataProvider and send now reject with an ApplicationError built from the server's error envelope, where they used to rethrow the parsed body.

What changed

• A real error. The body is read under the error root key and mapped like IGNIS HttpDataSource, so a repository and the data provider throw the same fields. Unlike HttpDataSource, message is the server's text and not a log line, because react-admin shows error.message. useNotifyError already typed its argument as an ApplicationError; it now gets one.
• What the fields hold.
  • statusCode is the HTTP status, always set.
  • message and normalized.text are the server's normalized.text, else its message, else HTTP <status>.
  • normalized.code is the server's code, or core.system_error when it sent none. normalized.args is the server's args or {}.
  • extra is the server's extra plus requestId, and undefined when both are empty. A relaying server's earlier extra.requestId moves to extra.upstreamRequestIds, nearest first.
  • cause is the server's details.cause, such as a 422's per-field issues.
• What is dropped. Any other key of the body (type, path, url, the rest of details, ad hoc fields such as field), and the top-level requestId, which is in extra.requestId now.
• Bodies that are not an envelope. A body that is not JSON, is empty, is an array, or holds a string under error no longer leaks a SyntaxError or throws a bare string. It becomes HTTP <status> with the default code. A body without the error key is read as it stands, so { message: 'Validation failed' } still gives that message.
• Content-Range. For getList and getManyReference, records a-b/N and records */N give N, and an absent header gives the page's row count, as before. A malformed header (records 0-24/*, 137, an empty string) now gives the row count too, where it gave NaN or the bare number.

Who is affected

• Code that reads error.statusCode, error.normalized.code, error.normalized.args or error.extra. No action needed.
• Code that reads error.requestId. Read error.extra?.requestId.
• Code that reads type, path, url, details or an ad hoc field off a caught error. These are no longer on it. details.cause is error.cause.
• Code that checks for a string, or catches a SyntaxError, from a failed request. An error body that is not an envelope is an ApplicationError with HTTP <status>.
• A checkError that matches on status. An ApplicationError has statusCode and no status, so a server body that carried a status key no longer reaches DefaultAuthProvider.checkError as one. The IGNIS envelope sends statusCode, which checkError does not read.
• Lists whose server sends a malformed Content-Range. total is the page's row count instead of NaN. Fix the header, or use CountRestDataProvider.

Breaking changes

WARNING

Narrow: only code that reads a field the old body carried but the envelope does not, or that depends on the thrown value not being an Error.

Before:

// The server answered 409 with:
// { error: { statusCode: 409, message: 'Order already paid', requestId: 'req-1', type: 'ConflictError' } }
// ...
try {
  await dataProvider.update('orders', { id: 7, data, previousData });
} catch (error) {
  // `error` was the parsed `error` object, whatever it held
  error.requestId; // 'req-1'
  error.type; // 'ConflictError'
  error instanceof Error; // false
  const copy = { ...error }; // has `message`
}

After:

// The same response
// ...
try {
  await dataProvider.update('orders', { id: 7, data, previousData });
} catch (error) {
  // `error` is an ApplicationError
  error.statusCode; // 409
  error.message; // 'Order already paid'
  error.extra?.requestId; // 'req-1'
  error.type; // undefined: dropped
  error instanceof Error; // true
  const copy = { ...error }; // no `message`: an Error keeps it as a non-enumerable own property
}

Migration guide

1. Replace error.requestId with error.extra?.requestId.
2. Replace a read of error.details.cause with error.cause. The other details keys, type, path and url are not on the error.
3. If you spread an error to copy it ({ ...error }), copy message explicitly: { ...error, message: error.message }.
4. If a catch branch tested typeof error === 'string' or error instanceof SyntaxError for a failed request, test error.statusCode instead.

See Network and Data provider.