What causes "Peer value already exists" in hcengineering/platform?

Check existence first (query the peer by key) and skip the insert if it already exists

Peer value already exists

Error message

Peer value already exists

What it means

createPeer in the CockroachDB implementation performs an INSERT ... ON CONFLICT DO NOTHING and then checks the affected row count. If zero rows were inserted, a peer record with the same key already exists, and it throws this plain Error. The method enforces peer uniqueness rather than silently overwriting or ignoring duplicates.

Source

Thrown at foundations/communication/packages/cockroach/src/db/peer.ts:59

    const db: DbModel<Domain.Peer> = {
      workspace_id: workspaceId,
      card_id: cardId,
      kind,
      value,
      extra,
      created: date
    }

    if (options?.newValue === true) {
      const { sql, values } = this.getInsertSql(Domain.Peer, db, [], {
        conflictColumns: ['workspace_id', 'kind', 'value'],
        conflictAction: 'DO NOTHING'
      })
      const result = await this.execute(sql, values, 'insert peer')
      const count = result?.count ?? 0

      if (count === 0) {
        throw Error('Peer value already exists')
      }
    } else {
      const { sql, values } = this.getInsertSql(Domain.Peer, db, [])
      await this.execute(sql, values, 'insert peer')
    }
  }

  async removePeer (workspaceId: WorkspaceUuid, cardId: CardID, kind: PeerKind, value: string): Promise<void> {
    const filter: DbModelFilter<Domain.Peer> = [
      {
        column: 'workspace_id',
        value: workspaceId
      },
      {
        column: 'card_id',
        value: cardId
      },
      {

View on GitHub (pinned to 63e28dc964)

Solutions

Check existence first (query the peer by key) and skip the insert if it already exists
Wrap createPeer in try-catch and treat 'Peer value already exists' as success for idempotent re-registration
Delete/upsert the existing peer row first (or use ON CONFLICT DO UPDATE) if replacing is intended
Serialize creation (e.g., per-peer lock) to avoid concurrent duplicate inserts

Example fix

// before
try { await db.createPeer(peer) } catch (e) { /* crash */ }
// after
try {
  await db.createPeer(peer)
} catch (e) {
  if (!(e instanceof Error && e.message === 'Peer value already exists')) throw e
  // treat as success: peer already registered
}

Defensive patterns

Strategy: try-catch

Validate before calling

const existing = await db.findPeer(peer.key)
if (existing) return existing // skip createPeer entirely

Type guard

function isDuplicatePeerError(e: unknown): e is Error {
  return e instanceof Error && e.message === 'Peer value already exists'
}

Try / catch

try {
  await db.createPeer(peer)
} catch (e) {
  if (isDuplicatePeerError(e)) return // idempotent re-registration
  throw e
}

Prevention

Treat createPeer as non-idempotent; check existence or catch duplicates on retry
Avoid concurrent createPeer calls for the same key (use per-key serialization)
Delete or upsert old peer rows before re-registering a node
Add retry logic that deduplicates on this specific error message

When it happens

Trigger: Calling createPeer (foundations/communication/packages/cockroach/src/db/peer.ts:59) when an INSERT into the Peer domain is a no-op due to ON CONFLICT DO NOTHING — i.e., a peer with the same unique key/value already exists in the table.

Common situations: Concurrent createPeer calls racing to insert the same peer (only one wins, the loser gets this error); retry logic re-invoking createPeer after a timeout when the first call actually succeeded; node re-registration without removing the old peer row; idempotency handling that assumes createPeer is safe to call twice.

Related errors

AI-assisted analysis of hcengineering/platform@63e28dc964 (2026-08-29). Data as JSON: /api/errors/0237ca96c154806a. Report an issue: GitHub.