Allow creating query errors without an error to wrap

dbutil/bulk.go

@@ -71,20 +71,23 @@ func BulkQuery[T any](ctx context.Context, db BulkQueryer, query string, structs
 
 	rows, err := db.QueryxContext(ctx, bulkQuery, args...)
 	if err != nil {
-		return NewQueryErrorf(err, bulkQuery, args, "error making bulk query")
+		return QueryErrorWrapf(err, bulkQuery, args, "error making bulk query")
 	}
 	defer rows.Close()
 
 	// if have a returning clause, read them back and try to map them
 	if strings.Contains(strings.ToUpper(query), "RETURNING") {
-		for _, s := range structs {
+		for i, s := range structs {
 			if !rows.Next() {
-				return errors.Errorf("did not receive expected number of rows on insert")
+				if rows.Err() != nil {
+					return QueryErrorWrapf(rows.Err(), bulkQuery, args, "missing returned row for struct %d", i)
+				}
+				return QueryErrorf(bulkQuery, args, "missing returned row for struct %d", i)
 			}
 
 			err = rows.StructScan(s)
 			if err != nil {
-				return errors.Wrap(err, "error scanning for returned values")
+				return QueryErrorWrapf(err, bulkQuery, args, "error scanning returned row %d", i)
 			}
 		}
 	}
@@ -94,11 +97,7 @@ func BulkQuery[T any](ctx context.Context, db BulkQueryer, query string, structs
 	}
 
 	// check for any error
-	if rows.Err() != nil {
-		return NewQueryErrorf(rows.Err(), bulkQuery, args, "error during row iteration")
-	}
-
-	return nil
+	return QueryErrorWrapf(rows.Err(), bulkQuery, args, "error during row iteration")
 }
 
 // extractValues is just a simple utility method that extracts the portion between `VALUE(`

dbutil/errors.go

@@ -25,7 +25,10 @@ type QueryError struct {
 }
 
 func (e *QueryError) Error() string {
-	return e.message + ": " + e.cause.Error()
+	if e.cause != nil {
+		return e.message + ": " + e.cause.Error()
+	}
+	return e.message
 }
 
 func (e *QueryError) Unwrap() error {
@@ -36,7 +39,18 @@ func (e *QueryError) Query() (string, []any) {
 	return e.sql, e.sqlArgs
 }
 
-func NewQueryErrorf(cause error, sql string, sqlArgs []any, message string, msgArgs ...any) error {
+func QueryErrorWrapf(cause error, sql string, sqlArgs []any, message string, msgArgs ...any) error {
+	if cause == nil {
+		return nil
+	}
+	return newQueryErrorf(cause, sql, sqlArgs, message, msgArgs...)
+}
+
+func QueryErrorf(sql string, sqlArgs []any, message string, msgArgs ...any) error {
+	return newQueryErrorf(nil, sql, sqlArgs, message, msgArgs...)
+}
+
+func newQueryErrorf(cause error, sql string, sqlArgs []any, message string, msgArgs ...any) error {
 	return &QueryError{
 		cause:   cause,
 		message: fmt.Sprintf(message, msgArgs...),

dbutil/errors_test.go

@@ -1,6 +1,7 @@
 package dbutil_test
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/lib/pq"
@@ -19,11 +20,18 @@ func TestIsUniqueViolation(t *testing.T) {
 }
 
 func TestQueryError(t *testing.T) {
+	qerr := dbutil.QueryErrorf("SELECT * FROM foo WHERE id = $1", []any{234}, "error selecting foo %d", 234)
+	assert.Error(t, qerr)
+	assert.Equal(t, `error selecting foo 234`, qerr.Error())
+	assert.Equal(t, `error selecting foo 234`, fmt.Sprintf("%s", qerr))
+
+	// can also wrap an existing error
 	var err error = &pq.Error{Code: pq.ErrorCode("22025"), Message: "unsupported Unicode escape sequence"}
 
-	qerr := dbutil.NewQueryErrorf(err, "SELECT * FROM foo WHERE id = $1", []any{234}, "error selecting foo %d", 234)
+	qerr = dbutil.QueryErrorWrapf(err, "SELECT * FROM foo WHERE id = $1", []any{234}, "error selecting foo %d", 234)
 	assert.Error(t, qerr)
 	assert.Equal(t, `error selecting foo 234: pq: unsupported Unicode escape sequence`, qerr.Error())
+	assert.Equal(t, `error selecting foo 234: pq: unsupported Unicode escape sequence`, fmt.Sprintf("%s", qerr))
 
 	// can unwrap to the original error
 	var pqerr *pq.Error
@@ -42,4 +50,7 @@ func TestQueryError(t *testing.T) {
 	query, params := unwrapped.Query()
 	assert.Equal(t, "SELECT * FROM foo WHERE id = $1", query)
 	assert.Equal(t, []any{234}, params)
+
+	// wrapping a nil error returns nil
+	assert.Nil(t, dbutil.QueryErrorWrapf(nil, "SELECT", nil, "ooh"))
 }