From e4e08e97fe2d1120789b1c88d69d09774be18fc7 Mon Sep 17 00:00:00 2001
From: tania <44262898+taniabogatsch@users.noreply.github.com>
Date: Thu, 21 Mar 2024 21:44:52 +0100
Subject: [PATCH] Bump Go version, unify errors and other refactoring (#187)

* started unifying errors

* nits

* trying to fix linter run failure by bumping the go version

* %w instead of %s

* fix more than one error-wrapping directive

* run gofumpt, bump go version everywhere

* fix freebsd run

* trigger tests

* battling CI

* revert to 1.21

* revert conn changes

* revert comment changes

* nit
---
 .github/workflows/golangci-lint.yml |  4 +-
 .github/workflows/tests.yaml        |  8 ++--
 appender.go                         |  3 +-
 appender_test.go                    | 21 ++++++----
 connection.go                       | 14 +++----
 duckdb.go                           | 64 ++++++++++++-----------------
 duckdb_test.go                      | 11 -----
 errors.go                           | 30 ++++++++++++++
 errors_test.go                      | 28 +++++++++++++
 go.mod                              |  2 +-
 go.sum                              |  5 +++
 rows.go                             |  1 -
 statement.go                        |  6 +--
 13 files changed, 120 insertions(+), 77 deletions(-)
 create mode 100644 errors.go
 create mode 100644 errors_test.go

diff --git a/.github/workflows/golangci-lint.yml b/.github/workflows/golangci-lint.yml
index 742252b2..fd63b922 100644
--- a/.github/workflows/golangci-lint.yml
+++ b/.github/workflows/golangci-lint.yml
@@ -10,12 +10,12 @@ jobs:
     name: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-go@v4
         with:
           go-version: '1.21'
           cache: false
       - name: golangci-lint
-        uses: golangci/golangci-lint-action@v3
+        uses: golangci/golangci-lint-action@v4
         with:
           version: latest
\ No newline at end of file
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 0cded2b5..515ab3ed 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -13,22 +13,22 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-12]
-        go: ["1.18"]
+        go: ["1.21"]
       fail-fast: false
 
     steps:
-      - uses: actions/setup-go@v2
+      - uses: actions/setup-go@v4
         with:
           go-version: ${{ matrix.go }}
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: "Run Tests"
         run: make test
   freebsd_amd64:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: vmactions/freebsd-vm@v1
         with:
           usesh: true
diff --git a/appender.go b/appender.go
index d4eca539..d9e98213 100644
--- a/appender.go
+++ b/appender.go
@@ -107,7 +107,7 @@ func NewAppenderFromConn(driverConn driver.Conn, schema, table string) (*Appende
 	defer C.free(unsafe.Pointer(cTable))
 
 	var appender C.duckdb_appender
-	state := C.duckdb_appender_create(*c.con, cSchema, cTable, &appender)
+	state := C.duckdb_appender_create(c.duckdbCon, cSchema, cTable, &appender)
 
 	if state == C.DuckDBError {
 		// We'll destroy the error message when destroying the appender.
@@ -242,7 +242,6 @@ func initPrimitive[T any](duckdbType C.duckdb_type) colInfo {
 }
 
 func (a *Appender) initColInfos(logicalType C.duckdb_logical_type, colIdx int) (colInfo, error) {
-
 	duckdbType := C.duckdb_get_type_id(logicalType)
 
 	switch duckdbType {
diff --git a/appender_test.go b/appender_test.go
index d511dfd8..6378ec23 100644
--- a/appender_test.go
+++ b/appender_test.go
@@ -5,11 +5,11 @@ import (
 	"database/sql"
 	"database/sql/driver"
 	"fmt"
-	"github.com/google/uuid"
 	"math/rand"
 	"testing"
 	"time"
 
+	"github.com/google/uuid"
 	"github.com/mitchellh/mapstructure"
 	"github.com/stretchr/testify/require"
 )
@@ -369,8 +369,10 @@ func TestAppenderNested(t *testing.T) {
 		rows[i].wrappedStruct = wrappedStruct{"wrapped", simpleStruct{1, "foo"}}
 		rows[i].doubleWrappedStruct = doubleWrappedStruct{
 			"so much nesting",
-			wrappedStruct{"wrapped",
-				simpleStruct{1, "foo"}},
+			wrappedStruct{
+				"wrapped",
+				simpleStruct{1, "foo"},
+			},
 		}
 		rows[i].structList = []simpleStruct{{1, "a"}, {2, "b"}, {3, "c"}}
 		rows[i].structWithList.L = []int32{6, 7, 8}
@@ -569,8 +571,10 @@ func TestAppenderNestedNullStruct(t *testing.T) {
 
 	err := appender.AppendRow(doubleWrappedStruct{
 		"so much nesting",
-		wrappedStruct{"wrapped",
-			simpleStruct{1, "foo"}},
+		wrappedStruct{
+			"wrapped",
+			simpleStruct{1, "foo"},
+		},
 	})
 	require.NoError(t, err)
 
@@ -580,8 +584,10 @@ func TestAppenderNestedNullStruct(t *testing.T) {
 
 	err = appender.AppendRow(doubleWrappedStruct{
 		"now we are done nesting NULLs",
-		wrappedStruct{"unwrap",
-			simpleStruct{21, "bar"}},
+		wrappedStruct{
+			"unwrap",
+			simpleStruct{21, "bar"},
+		},
 	})
 	require.NoError(t, err)
 
@@ -1016,7 +1022,6 @@ func TestAppenderUint8SliceTinyInt(t *testing.T) {
 }
 
 func TestAppenderUnsupportedType(t *testing.T) {
-
 	connector, err := NewConnector("", nil)
 	require.NoError(t, err)
 
diff --git a/connection.go b/connection.go
index bcb80a8c..63ae13d7 100644
--- a/connection.go
+++ b/connection.go
@@ -16,9 +16,9 @@ import (
 )
 
 type conn struct {
-	con    *C.duckdb_connection
-	closed bool
-	tx     bool
+	duckdbCon C.duckdb_connection
+	closed    bool
+	tx        bool
 }
 
 func (c *conn) CheckNamedValue(nv *driver.NamedValue) error {
@@ -146,7 +146,7 @@ func (c *conn) Close() error {
 	}
 	c.closed = true
 
-	C.duckdb_disconnect(c.con)
+	C.duckdb_disconnect(&c.duckdbCon)
 
 	return nil
 }
@@ -156,7 +156,7 @@ func (c *conn) prepareStmt(cmd string) (*stmt, error) {
 	defer C.free(unsafe.Pointer(cmdstr))
 
 	var s C.duckdb_prepared_statement
-	if state := C.duckdb_prepare(*c.con, cmdstr, &s); state == C.DuckDBError {
+	if state := C.duckdb_prepare(c.duckdbCon, cmdstr, &s); state == C.DuckDBError {
 		dbErr := C.GoString(C.duckdb_prepare_error(s))
 		C.duckdb_destroy_prepare(&s)
 		return nil, errors.New(dbErr)
@@ -170,7 +170,7 @@ func (c *conn) extractStmts(query string) (C.duckdb_extracted_statements, C.idx_
 	defer C.free(unsafe.Pointer(cquery))
 
 	var stmts C.duckdb_extracted_statements
-	stmtsCount := C.duckdb_extract_statements(*c.con, cquery, &stmts)
+	stmtsCount := C.duckdb_extract_statements(c.duckdbCon, cquery, &stmts)
 	if stmtsCount == 0 {
 		err := C.GoString(C.duckdb_extract_statements_error(stmts))
 		C.duckdb_destroy_extracted(&stmts)
@@ -185,7 +185,7 @@ func (c *conn) extractStmts(query string) (C.duckdb_extracted_statements, C.idx_
 
 func (c *conn) prepareExtractedStmt(extractedStmts C.duckdb_extracted_statements, index C.idx_t) (*stmt, error) {
 	var s C.duckdb_prepared_statement
-	if state := C.duckdb_prepare_extracted_statement(*c.con, extractedStmts, index, &s); state == C.DuckDBError {
+	if state := C.duckdb_prepare_extracted_statement(c.duckdbCon, extractedStmts, index, &s); state == C.DuckDBError {
 		dbErr := C.GoString(C.duckdb_prepare_error(s))
 		C.duckdb_destroy_prepare(&s)
 		return nil, errors.New(dbErr)
diff --git a/duckdb.go b/duckdb.go
index 53e7f321..bbbce698 100644
--- a/duckdb.go
+++ b/duckdb.go
@@ -14,7 +14,6 @@ import (
 	"context"
 	"database/sql"
 	"database/sql/driver"
-	"errors"
 	"fmt"
 	"net/url"
 	"strings"
@@ -28,11 +27,11 @@ func init() {
 type Driver struct{}
 
 func (d Driver) Open(dsn string) (driver.Conn, error) {
-	connector, err := d.OpenConnector(dsn)
+	c, err := d.OpenConnector(dsn)
 	if err != nil {
 		return nil, err
 	}
-	return connector.Connect(context.Background())
+	return c.Connect(context.Background())
 }
 
 func (Driver) OpenConnector(dsn string) (driver.Connector, error) {
@@ -42,14 +41,14 @@ func (Driver) OpenConnector(dsn string) (driver.Connector, error) {
 }
 
 // NewConnector opens a new Connector for a DuckDB database.
-// The user must close the returned Connector, if it is not passed to the sql.OpenDB function.
+// The user must close the Connector, if it is not passed to the sql.OpenDB function.
 // Otherwise, sql.DB closes the Connector when calling sql.DB.Close().
 func NewConnector(dsn string, connInitFn func(execer driver.ExecerContext) error) (*Connector, error) {
 	var db C.duckdb_database
 
 	parsedDSN, err := url.Parse(dsn)
 	if err != nil {
-		return nil, fmt.Errorf("%w: %s", errParseDSN, err.Error())
+		return nil, getError(errParseDSN, err)
 	}
 
 	config, err := prepareConfig(parsedDSN)
@@ -58,14 +57,14 @@ func NewConnector(dsn string, connInitFn func(execer driver.ExecerContext) error
 	}
 	defer C.duckdb_destroy_config(&config)
 
-	connStr := C.CString(extractConnectionString(dsn))
+	connStr := C.CString(getConnString(dsn))
 	defer C.free(unsafe.Pointer(connStr))
 
-	var errOpenMsg *C.char
-	defer C.duckdb_free(unsafe.Pointer(errOpenMsg))
+	var outError *C.char
+	defer C.duckdb_free(unsafe.Pointer(outError))
 
-	if state := C.duckdb_open_ext(connStr, &db, config, &errOpenMsg); state == C.DuckDBError {
-		return nil, fmt.Errorf("%w: %s", errOpen, C.GoString(errOpenMsg))
+	if state := C.duckdb_open_ext(connStr, &db, config, &outError); state == C.DuckDBError {
+		return nil, getError(errOpen, getDuckDBError(outError))
 	}
 
 	return &Connector{
@@ -79,26 +78,25 @@ type Connector struct {
 	connInitFn func(execer driver.ExecerContext) error
 }
 
-func (c *Connector) Driver() driver.Driver {
+func (*Connector) Driver() driver.Driver {
 	return Driver{}
 }
 
 func (c *Connector) Connect(context.Context) (driver.Conn, error) {
-	var con C.duckdb_connection
-	if state := C.duckdb_connect(c.db, &con); state == C.DuckDBError {
-		return nil, errOpen
+	var duckdbCon C.duckdb_connection
+	if state := C.duckdb_connect(c.db, &duckdbCon); state == C.DuckDBError {
+		return nil, getError(errConnect, nil)
 	}
 
-	conn := &conn{con: &con}
+	con := &conn{duckdbCon: duckdbCon}
 
-	// Call the connection init function if defined
 	if c.connInitFn != nil {
-		if err := c.connInitFn(conn); err != nil {
+		if err := c.connInitFn(con); err != nil {
 			return nil, err
 		}
 	}
 
-	return conn, nil
+	return con, nil
 }
 
 func (c *Connector) Close() error {
@@ -107,27 +105,26 @@ func (c *Connector) Close() error {
 	return nil
 }
 
-func extractConnectionString(dsn string) string {
-	var queryIndex = strings.Index(dsn, "?")
-	if queryIndex < 0 {
-		queryIndex = len(dsn)
+func getConnString(dsn string) string {
+	idx := strings.Index(dsn, "?")
+	if idx < 0 {
+		idx = len(dsn)
 	}
-
-	return dsn[0:queryIndex]
+	return dsn[0:idx]
 }
 
 func prepareConfig(parsedDSN *url.URL) (C.duckdb_config, error) {
 	var config C.duckdb_config
 	if state := C.duckdb_create_config(&config); state == C.DuckDBError {
 		C.duckdb_destroy_config(&config)
-		return nil, errCreateConfig
+		return nil, getError(errCreateConfig, nil)
 	}
 
-	if err := setConfig(config, "duckdb_api", "go"); err != nil {
+	if err := setConfigOption(config, "duckdb_api", "go"); err != nil {
 		return nil, err
 	}
 
-	// early-out
+	// Early-out, if the DSN does not contain configuration options.
 	if len(parsedDSN.RawQuery) == 0 {
 		return config, nil
 	}
@@ -136,7 +133,7 @@ func prepareConfig(parsedDSN *url.URL) (C.duckdb_config, error) {
 		if len(v) == 0 {
 			continue
 		}
-		if err := setConfig(config, k, v[0]); err != nil {
+		if err := setConfigOption(config, k, v[0]); err != nil {
 			return nil, err
 		}
 	}
@@ -144,7 +141,7 @@ func prepareConfig(parsedDSN *url.URL) (C.duckdb_config, error) {
 	return config, nil
 }
 
-func setConfig(config C.duckdb_config, name string, option string) error {
+func setConfigOption(config C.duckdb_config, name string, option string) error {
 	cName := C.CString(name)
 	defer C.free(unsafe.Pointer(cName))
 
@@ -154,15 +151,8 @@ func setConfig(config C.duckdb_config, name string, option string) error {
 	state := C.duckdb_set_config(config, cName, cOption)
 	if state == C.DuckDBError {
 		C.duckdb_destroy_config(&config)
-		return fmt.Errorf("%w: %s=%s is not a global config option or does not exist", errSetConfig, name, option)
+		return getError(errSetConfig, fmt.Errorf("%s=%s", name, option))
 	}
 
 	return nil
 }
-
-var (
-	errOpen         = errors.New("could not open database")
-	errParseDSN     = errors.New("could not parse DSN for database")
-	errCreateConfig = errors.New("could not create config for database")
-	errSetConfig    = errors.New("could not set config option for database")
-)
diff --git a/duckdb_test.go b/duckdb_test.go
index 888e194c..6bcbdabd 100644
--- a/duckdb_test.go
+++ b/duckdb_test.go
@@ -51,16 +51,6 @@ func TestOpen(t *testing.T) {
 		require.NoError(t, res.Scan(&species))
 		require.Equal(t, "Gopher", species)
 	})
-
-	t.Run("with invalid config", func(t *testing.T) {
-		_, err := sql.Open("duckdb", "?threads=NaN")
-		require.Contains(t, err.Error(), "is not a global config option or does not exist")
-	})
-
-	t.Run("with connection-local config", func(t *testing.T) {
-		_, err := sql.Open("duckdb", "?schema=main")
-		require.Contains(t, err.Error(), "is not a global config option or does not exist")
-	})
 }
 
 func TestConnectorBootQueries(t *testing.T) {
@@ -677,7 +667,6 @@ func TestBlob(t *testing.T) {
 }
 
 func TestTimestampTZ(t *testing.T) {
-
 	t.Parallel()
 	db := openDB(t)
 	defer db.Close()
diff --git a/errors.go b/errors.go
new file mode 100644
index 00000000..88bb474e
--- /dev/null
+++ b/errors.go
@@ -0,0 +1,30 @@
+package duckdb
+
+import "C"
+import (
+	"errors"
+	"fmt"
+)
+
+func getError(errDriver error, err error) error {
+	if err == nil {
+		return fmt.Errorf("%s: %w", driverErrMsg, errDriver)
+	}
+	return fmt.Errorf("%s: %w: %s", driverErrMsg, errDriver, err.Error())
+}
+
+func getDuckDBError(err *C.char) error {
+	return errors.New(C.GoString(err))
+}
+
+const driverErrMsg = "database/sql/driver"
+
+var (
+	errParseDSN  = errors.New("could not parse DSN for database")
+	errOpen      = errors.New("could not open database")
+	errSetConfig = errors.New("could not set invalid or local option for global database config")
+
+	// Errors not covered in tests.
+	errConnect      = errors.New("could not connect to database")
+	errCreateConfig = errors.New("could not create config for database")
+)
diff --git a/errors_test.go b/errors_test.go
new file mode 100644
index 00000000..d0971da5
--- /dev/null
+++ b/errors_test.go
@@ -0,0 +1,28 @@
+package duckdb
+
+import (
+	"database/sql"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var testErrOpenMap = map[string]string{
+	errParseDSN.Error():  ":mem ory:",
+	errOpen.Error():      "?readonly",
+	errSetConfig.Error(): "?threads=NaN",
+}
+
+func TestErrOpen(t *testing.T) {
+	for errMsg, dsn := range testErrOpenMap {
+		t.Run(errMsg, func(t *testing.T) {
+			_, err := sql.Open("duckdb", dsn)
+			require.Contains(t, err.Error(), errMsg)
+		})
+	}
+
+	t.Run("local config option", func(t *testing.T) {
+		_, err := sql.Open("duckdb", "?schema=main")
+		require.Contains(t, err.Error(), errSetConfig.Error())
+	})
+}
diff --git a/go.mod b/go.mod
index 5cbb0b56..0b1eceda 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/marcboeker/go-duckdb
 
-go 1.18
+go 1.21
 
 require (
 	github.com/apache/arrow/go/v14 v14.0.2
diff --git a/go.sum b/go.sum
index 92bb61f8..58903a2d 100644
--- a/go.sum
+++ b/go.sum
@@ -17,6 +17,7 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/pierrec/lz4/v4 v4.1.18 h1:xaKrnTkyoqfh1YItXl56+6KJNVYWlEEPuAQW9xsplYQ=
@@ -26,12 +27,15 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
+github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
 github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
 github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/mod v0.13.0 h1:I/DsJXRlw/8l/0c24sM9yb0T4z9liZTduXvdAWYiysY=
 golang.org/x/mod v0.13.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
 golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -40,6 +44,7 @@ golang.org/x/tools v0.14.0/go.mod h1:uYBEerGOWcJyEORxN+Ek8+TT266gXkNlHdJBwexUsBg
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 h1:H2TDz8ibqkAF6YGhCdN3jS9O0/s90v0rJh3X/OLHEUk=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 gonum.org/v1/gonum v0.12.0 h1:xKuo6hzt+gMav00meVPUlXwSdoEJP46BR+wdxQEFK2o=
+gonum.org/v1/gonum v0.12.0/go.mod h1:73TDxJfAAHeA8Mk9mf8NlIppyhQNo5GLTcYeqgo2lvY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
diff --git a/rows.go b/rows.go
index 5217380e..35159304 100644
--- a/rows.go
+++ b/rows.go
@@ -95,7 +95,6 @@ func scanValue(vector C.duckdb_vector, rowIdx C.idx_t) (any, error) {
 }
 
 func scan(vector C.duckdb_vector, rowIdx C.idx_t) (any, error) {
-
 	// FIXME: implement support for these types:
 	// DUCKDB_TYPE_UHUGEINT
 	// DUCKDB_TYPE_UNION
diff --git a/statement.go b/statement.go
index 7bf51ff6..99e85c78 100644
--- a/statement.go
+++ b/statement.go
@@ -210,7 +210,7 @@ func (s *stmt) execute(ctx context.Context, args []driver.NamedValue) (*C.duckdb
 	go func() {
 		select {
 		case <-ctx.Done():
-			C.duckdb_interrupt(*s.c.con)
+			C.duckdb_interrupt(s.c.duckdbCon)
 			close(bgDoneCh)
 			return
 		case <-mainDoneCh:
@@ -249,6 +249,4 @@ func argsToNamedArgs(values []driver.Value) []driver.NamedValue {
 	return args
 }
 
-var (
-	errCouldNotBind = errors.New("could not bind parameter")
-)
+var errCouldNotBind = errors.New("could not bind parameter")