addPieces fails with "value.length" error when metadata entry value is undefined

[ishtails]

Description

Problem

During addPieces, the SDK can throw:

undefined is not an object (evaluating 'value.length')

Wrapped as:

StorageContext addPieces failed: Failed to add piece to data set - undefined is not an object (evaluating 'value.length')

Cause

In packages/synapse-core/src/utils/metadata.ts, both pieceMetadataObjectToEntry and datasetMetadataObjectToEntry do:

for (const entry of entries) {
  if (entry.key.length > METADATA_LIMITS.MAX_KEY_LENGTH) { ... }
  if (entry.value.length > METADATA_LIMITS.MAX_VALUE_LENGTH) {  // crashes if entry.value is undefined

MetadataObject is Record<string, string>, but that is not enforced at runtime. If any metadata entry has undefined as a value (e.g. from { key: undefined } or metadataInternal.ipfsRootCID being undefined), entry.value.length throws.

Impact

• Unhandled promise rejection can crash the server
• Upload to the storage provider succeeds, but the piece is not added to the data set
• File remains in S3; users can still view/sign, but pieces are not registered on-chain

Suggested fix

Validate entry.value before using it:

Either add null/undefined check like this:

for (const entry of entries) {
  if (entry.key.length > METADATA_LIMITS.MAX_KEY_LENGTH) {
    throw new Error('Metadata key exceeds the maximum length')
  }
  if (entry.value == null || String(entry.value).length > METADATA_LIMITS.MAX_VALUE_LENGTH) {
    throw new Error('Metadata value exceeds the maximum length')
  }
}

Or filter invalid entries:

const entries = Object.entries(obj)
  .filter(([, value]) => value != null && typeof value === 'string')
  .sort((a, b) => a[0].localeCompare(b[0]))
  .map(([key, value]) => ({ key, value }))

Will have to apply the same logic in both pieceMetadataObjectToEntry and datasetMetadataObjectToEntry.

---

Environment

• @filoz/synapse-sdk@0.37.0
• @filoz/synapse-core@0.2.0

---

Reproduction

1. Create a storage context with metadata: { filosign_user: walletAddress }
2. Upload a piece with metadata: {}
3. After the piece is uploaded to the SP, addPieces fails when processing the pending pieces batch

[rjan90]

Thanks for the report @ishtails! Does any of the suggested fixes here look okay to you @hugomrdias?