pubkey/rxdb · error · RxError

SNH

SNH

Error message

        RxDB Error-Code: ${message}.
        Hint: Error messages are not included in RxDB core to reduce build size.
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        use the dev-mode plugin when you are in development mode: https://rxdb.info/dev-mode.html?console=error
        
Find out more about this error here: https://rxdb.info/errors.html?console=errors#SNH 
Still stuck? Ask in the RxDB Discord: https://rxdb.info/chat

What it means

SNH stands for 'should not happen' and marks an internal invariant violation. In categorizeBulkWriteRows (src/rx-storage-helper.ts:500), RxDB categorizes each bulk-write row into INSERT, UPDATE or DELETE events. If a successfully written row cannot be classified into one of these three operations, the state is impossible under RxDB's assumptions and SNH is thrown. This is a bug signal, not a validation error: user input that is wrong is normally rejected earlier with a dedicated error code.

Source

Thrown at src/rx-storage-helper.ts:500

            let operation: 'INSERT' | 'UPDATE' | 'DELETE';

            if (previousDeleted && !documentDeleted) {
                operation = 'INSERT';
                /**
                 * Reuse the already-stripped document from updatedRow
                 * instead of calling stripAttachmentsDataFromDocument() again.
                 */
                eventDocumentData = hasAttachments ? updatedRow.document : document as any;
            } else if (previous && !previousDeleted && !documentDeleted) {
                operation = 'UPDATE';
                eventDocumentData = hasAttachments ? updatedRow.document : document as any;
                previousEventDocumentData = previous;
            } else if (documentDeleted) {
                operation = 'DELETE';
                eventDocumentData = ensureNotFalsy(document) as any;
                previousEventDocumentData = previous;
            } else {
                throw newRxError('SNH', { args: { writeRow } });
            }

            const event = {
                documentId: docId,
                documentData: eventDocumentData as RxDocumentData<RxDocType>,
                previousDocumentData: previousEventDocumentData,
                operation: operation
            };
            eventBulkEvents.push(event);
        }
    }

    return {
        bulkInsertDocs,
        bulkUpdateDocs,
        newestRow,
        errors,
        eventBulk,

View on GitHub (pinned to af6fb65f94)

Solutions

  1. Inspect err.parameters.args.writeRow to see the offending row (document, previous state, deleted flags).
  2. Report it as a bug to RxDB (https://github.com/pubkey/rxdb/issues) including the writeRow parameters, because this branch marks an internal invariant violation.
  3. Check that all RxDB plugins and any custom RxStorage are version-matched with the RxDB core version.
  4. If a custom storage is involved, verify its bulkWrite() returns previousDocumentData and deleted flags consistent with the RxStorageInstance contract.
  5. As a workaround, clear/repair the affected storage data so the inconsistent row state is removed, then retry.
Defensive patterns

Strategy: try-catch

Try / catch

try {
  await collection.bulkInsert(docs);
} catch (err) {
  if (err && err.code === 'SNH') {
    // internal invariant violation: capture state and report as a bug
    console.error('RxDB SNH in bulk write, row:', JSON.stringify(err.parameters.args, null, 2));
    reportBug(err); // e.g. send to your error tracker
    return;
  }
  throw err;
}

Prevention

When it happens

Trigger: A row that passed conflict and validation checks but whose previous document state and deleted flags match none of the three expected combinations (previousDeleted&&!documentDeleted, previous&&!previousDeleted&&!documentDeleted, documentDeleted). In practice: a storage implementation or plugin (custom RxStorage, sharding, replication wrapper) feeding corrupted or inconsistent rows into categorizeBulkWriteRows, or a race where the underlying storage returns inconsistent bulk-write results.

Common situations: Developing or using a third-party RxStorage plugin that returns wrong previousDocument/deleted data from bulkWrite(); using an outdated or incompatible RxStorage/plugin version with a newer RxDB core; concurrent writes from multiple processes bypassing RxDB's conflict handling so the storage returns a state RxDB did not expect.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of pubkey/rxdb@af6fb65f94 (2026-08-31). Data as JSON: /api/errors/3c4b0077229f6b65. Report an issue: GitHub.