From 7bb1640a00fceca1e1075fe6544b9a4842ab2b26 Mon Sep 17 00:00:00 2001
From: Vladimir Mihailenco <vladimir.webdev@gmail.com>
Date: Tue, 22 Feb 2022 13:30:10 +0200
Subject: [PATCH] fix: check for nils when appeding driver.Value

---
 .github/workflows/build.yml |  4 ++--
 internal/dbtest/db_test.go  | 28 ++++++++++++++++++++++++++++
 schema/append_value.go      | 19 +++++++++++++++++--
 3 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 83fb80360..3d95db7b7 100755
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -69,7 +69,7 @@ jobs:
           MSSQL_USER: sa
           MSSQL_PASSWORD: passWORD1
         ports:
-          - 14339:1433
+          - 1433:1433
         options: >-
           --health-cmd="/opt/mssql-tools/bin/sqlcmd -S tcp:localhost,1433 -U sa -P passWORD1 -Q
           'select 1' -b -o /dev/null" --health-interval=10s --health-timeout=5s --health-retries=5
@@ -90,4 +90,4 @@ jobs:
           MYSQL: user:pass@/test
           MYSQL5: user:pass@tcp(localhost:53306)/test
           MARIADB: user:pass@tcp(localhost:13306)/test
-          MSSQL2019: sqlserver://sa:passWORD1@localhost:14339?database=test
+          MSSQL2019: sqlserver://sa:passWORD1@localhost:1433?database=master
diff --git a/internal/dbtest/db_test.go b/internal/dbtest/db_test.go
index 6b9439414..404e8cdf2 100644
--- a/internal/dbtest/db_test.go
+++ b/internal/dbtest/db_test.go
@@ -269,6 +269,7 @@ func TestDB(t *testing.T) {
 		{testEmbedModelValue},
 		{testEmbedModelPointer},
 		{testJSONMarshaler},
+		{testNilDriverValue},
 	}
 
 	testEachDB(t, func(t *testing.T, dbName string, db *bun.DB) {
@@ -1284,3 +1285,30 @@ func testJSONMarshaler(t *testing.T, db *bun.DB) {
 	require.NoError(t, err)
 	require.Equal(t, "bar", m2.Field.Foo)
 }
+
+type DriverValue struct {
+	s string
+}
+
+var _ driver.Valuer = (*DriverValue)(nil)
+
+func (v *DriverValue) Value() (driver.Value, error) {
+	return v.s, nil
+}
+
+func testNilDriverValue(t *testing.T, db *bun.DB) {
+	type Model struct {
+		Value *DriverValue `bun:"type:varchar(100)"`
+	}
+
+	ctx := context.Background()
+
+	err := db.ResetModel(ctx, (*Model)(nil))
+	require.NoError(t, err)
+
+	_, err = db.NewInsert().Model(&Model{}).Exec(ctx)
+	require.NoError(t, err)
+
+	_, err = db.NewInsert().Model(&Model{Value: &DriverValue{s: "hello"}}).Exec(ctx)
+	require.NoError(t, err)
+}
diff --git a/schema/append_value.go b/schema/append_value.go
index e6587cd6e..c805c745f 100644
--- a/schema/append_value.go
+++ b/schema/append_value.go
@@ -105,15 +105,21 @@ func appender(dialect Dialect, typ reflect.Type) AppenderFunc {
 		return appendJSONRawMessageValue
 	}
 
+	kind := typ.Kind()
+
 	if typ.Implements(queryAppenderType) {
+		if kind == reflect.Ptr {
+			return nilAwareAppender(appendQueryAppenderValue)
+		}
 		return appendQueryAppenderValue
 	}
 	if typ.Implements(driverValuerType) {
+		if kind == reflect.Ptr {
+			return nilAwareAppender(appendDriverValue)
+		}
 		return appendDriverValue
 	}
 
-	kind := typ.Kind()
-
 	if kind != reflect.Ptr {
 		ptr := reflect.PtrTo(typ)
 		if ptr.Implements(queryAppenderType) {
@@ -156,6 +162,15 @@ func ifaceAppenderFunc(fmter Formatter, b []byte, v reflect.Value) []byte {
 	return appender(fmter, b, elem)
 }
 
+func nilAwareAppender(fn AppenderFunc) AppenderFunc {
+	return func(fmter Formatter, b []byte, v reflect.Value) []byte {
+		if v.IsNil() {
+			return dialect.AppendNull(b)
+		}
+		return fn(fmter, b, v)
+	}
+}
+
 func PtrAppender(fn AppenderFunc) AppenderFunc {
 	return func(fmter Formatter, b []byte, v reflect.Value) []byte {
 		if v.IsNil() {