allow before insert trigger to specify missing column

enginetest/queries/script_queries.go

@@ -2810,7 +2810,7 @@ CREATE TABLE tab3 (
 			},
 			{
 				Query:       "INSERT INTO test (pk) VALUES (3);",
-				ExpectedErr: sql.ErrInsertIntoNonNullableDefaultNullColumn,
+				ExpectedErr: sql.ErrInsertIntoNonNullableProvidedNull,
 			},
 			{
 				Query:       "ALTER TABLE test ALTER v2 DROP DEFAULT;",
@@ -2826,7 +2826,7 @@ CREATE TABLE tab3 (
 			},
 			{
 				Query:       "INSERT INTO test (pk) VALUES (2);",
-				ExpectedErr: sql.ErrInsertIntoNonNullableDefaultNullColumn,
+				ExpectedErr: sql.ErrInsertIntoNonNullableProvidedNull,
 			},
 			{
 				Query:    "ALTER TABLE test ALTER v1 SET DEFAULT 100, alter v1 SET DEFAULT 200",

enginetest/queries/trigger_queries.go

@@ -506,6 +506,92 @@ var TriggerTests = []ScriptTest{
 			},
 		},
 	},
+	{
+		Name: "insert trigger with missing column default value",
+		SetUpScript: []string{
+			"CREATE TABLE t (i INT PRIMARY KEY, j INT NOT NULL);",
+			`
+CREATE TRIGGER trig BEFORE INSERT ON t 
+FOR EACH ROW
+BEGIN
+    SET new.j = 10;
+END;`,
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "INSERT INTO t (i) VALUES (1);",
+				Expected: []sql.Row{
+					{types.OkResult{RowsAffected: 1}},
+				},
+			},
+			{
+				Query: "INSERT INTO t (i, j) VALUES (2, null);",
+				Expected: []sql.Row{
+					{types.OkResult{RowsAffected: 1}},
+				},
+			},
+			{
+				Query: "SELECT * FROM t;",
+				Expected: []sql.Row{
+					{1, 10},
+					{2, 10},
+				},
+			},
+		},
+	},
+	{
+		Name: "not null column with trigger that sets null should error",
+		SetUpScript: []string{
+			"CREATE TABLE t (i INT PRIMARY KEY, j INT NOT NULL);",
+			`
+CREATE TRIGGER trig BEFORE INSERT ON t 
+FOR EACH ROW
+BEGIN
+    SET new.j = null;
+END;`,
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query:       "INSERT INTO t (i) VALUES (1);",
+				ExpectedErr: sql.ErrInsertIntoNonNullableProvidedNull,
+			},
+			{
+				Query:       "INSERT INTO t (i, j) VALUES (1, 2);",
+				ExpectedErr: sql.ErrInsertIntoNonNullableProvidedNull,
+			},
+		},
+	},
+	{
+		Name: "not null column with before insert trigger should error",
+		SetUpScript: []string{
+			"CREATE TABLE t (i INT PRIMARY KEY, j INT NOT NULL);",
+			`
+CREATE TRIGGER trig BEFORE INSERT ON t 
+FOR EACH ROW
+BEGIN
+    SET new.i = 10 * new.i;
+END;`,
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "INSERT INTO t (i) VALUES (1);",
+				// TODO: should be sql.ErrInsertIntoNonNullableDefaultNullColumn
+				ExpectedErr: sql.ErrInsertIntoNonNullableProvidedNull,
+			},
+			{
+				Query: "INSERT INTO t (i, j) VALUES (1, 2);",
+				Expected: []sql.Row{
+					{types.NewOkResult(1)},
+				},
+			},
+			{
+				Query: "SELECT * FROM t;",
+				Expected: []sql.Row{
+					{10, 2},
+				},
+			},
+		},
+	},
 
 	// UPDATE triggers
 	{

sql/analyzer/inserts.go

@@ -123,15 +123,11 @@ func wrapRowSource(ctx *sql.Context, insertSource sql.Node, destTbl sql.Table, s
 
 	for i, col := range schema {
 		colIdx := findColIdx(col.Name, columnNames)
-		// if column was not explicitly specified, try to substitute with default or generated value
 		if colIdx == -1 {
 			defaultExpr := col.Default
 			if defaultExpr == nil {
 				defaultExpr = col.Generated
 			}
-			if !col.Nullable && defaultExpr == nil && !col.AutoIncrement {
-				return nil, -1, sql.ErrInsertIntoNonNullableDefaultNullColumn.New(col.Name)
-			}
 
 			var err error
 			colNameToIdx := make(map[string]int)

sql/rowexec/insert.go

@@ -393,14 +393,19 @@ func (i *insertIter) evaluateChecks(ctx *sql.Context, row sql.Row) error {
 
 func (i *insertIter) validateNullability(ctx *sql.Context, dstSchema sql.Schema, row sql.Row) error {
 	for count, col := range dstSchema {
-		if !col.Nullable && row[count] == nil {
+		if row[count] != nil {
+			continue
+		}
+		if !col.Nullable {
 			// In the case of an IGNORE we set the nil value to a default and add a warning
-			if i.ignore {
-				row[count] = col.Type.Zero()
-				_ = warnOnIgnorableError(ctx, row, sql.ErrInsertIntoNonNullableProvidedNull.New(col.Name)) // will always return nil
-			} else {
+			if !i.ignore {
+				if col.Default != nil || col.Generated != nil {
+					return sql.ErrInsertIntoNonNullableDefaultNullColumn.New(col.Name)
+				}
 				return sql.ErrInsertIntoNonNullableProvidedNull.New(col.Name)
 			}
+			row[count] = col.Type.Zero()
+			_ = warnOnIgnorableError(ctx, row, sql.ErrInsertIntoNonNullableProvidedNull.New(col.Name)) // will always return nil
 		}
 	}
 	return nil