gastownhall/beads · error

count edges in %s: scan: %w

Error message

count edges in %s: scan: %w

What it means

tallyEdgesInTx failed while scanning a row of the grouped edge-count result into (id string, count int64). rows.Scan returned an error because the returned columns did not match the expected string/int64 shapes. The rows are closed before returning so the connection is not leaked.

Source

Thrown at internal/storage/issueops/edge_counts.go:158

			end := start + queryBatchSize
			if end > len(anchors) {
				end = len(anchors)
			}
			batch := anchors[start:end]
			query := buildEdgeCountQuery(plane.dependencies, plane.sources, len(batch), request)
			rows, err := tx.QueryContext(ctx, query, edgeCountArgs(batch, request)...)
			if err != nil {
				if optionalBlockedTable(plane.dependencies) && isTableNotExistError(err) {
					break
				}
				return nil, fmt.Errorf("count edges in %s: %w", plane.dependencies, err)
			}
			for rows.Next() {
				var id string
				var n int64
				if scanErr := rows.Scan(&id, &n); scanErr != nil {
					_ = rows.Close()
					return nil, fmt.Errorf("count edges in %s: scan: %w", plane.dependencies, scanErr)
				}
				tallies[id] += n
			}
			_ = rows.Close()
			if err := rows.Err(); err != nil {
				return nil, fmt.Errorf("count edges in %s: rows: %w", plane.dependencies, err)
			}
		}
	}
	return tallies, nil
}

// buildEdgeCountQuery returns the grouped count for one dependency plane, keyed
// by the anchor end the request's direction names.
//
// THE TARGET END IS ALWAYS THE COALESCE EXPRESSION, never the STORED generated
// `depends_on_id` column. Both dependency tables define that column as
// GENERATED ALWAYS AS the same COALESCE, and inside an aggregate the pure-Go

View on GitHub (pinned to 71377f2769)

Solutions

1. Check the driver's type mapping for COUNT/aggregate results (e.g. uint64 vs int64) and pin a supported driver version.
2. Make the query's COALESCE/COUNT output non-NULL and compatible (CAST if needed).
3. Inspect the wrapped scan error message — it names the offending column and Go type.
4. If the code was customized, re-align rows.Scan with buildEdgeCountQuery's SELECT list.

Example fix

// before
var n int64
if scanErr := rows.Scan(&id, &n); scanErr != nil { ... }
// after
var n any // or uint64, matching the driver
count, ok := n.(uint64)
if ok { n = int64(count) }

res, err := ExecuteEdgeCount(ctx, tx, req)
if err != nil && strings.Contains(err.Error(), ": scan: ") {
	log.Errorf("edge count scan failure: %v", err) // inspect driver type mapping
}

When it happens

Trigger: A driver returning columns whose Go types cannot convert to string/int64 (e.g. NULL id, a count column typed as unsigned bigint beyond int64, or a decimal count from a custom COUNT expression); a driver mismatch producing different column types than Dolt normally does.

Common situations: Using a non-Dolt/MySQL driver or a driver version whose type mapping changed; a schema where the id column is nullable and a NULL row appears; a modified buildEdgeCountQuery selecting an extra/different column while the scan still expects two.

Related errors

• check issue existence in %s: scan: %w
• %s: %w
• failed to scan federation peer: %w
• db: ChildCounterSQLRepository.NextChildID: scan: %w
• db: CommentSQLRepository.CountsByIssueIDs: scan: %w

AI-assisted analysis of gastownhall/beads@71377f2769 (2026-08-30). Data as JSON: /api/errors/7bf7ed0e8654e663. Report an issue: GitHub.