From 0787da18162525af8dda2ac5f4dbac96304813c7 Mon Sep 17 00:00:00 2001
From: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
Date: Thu, 21 Dec 2023 23:07:13 +0200
Subject: [PATCH] schemadiff: allow char->varchar FK reference type matching

Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>
---
 go/vt/schemadiff/schema.go      | 3 +++
 go/vt/schemadiff/schema_test.go | 7 +++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/go/vt/schemadiff/schema.go b/go/vt/schemadiff/schema.go
index 5e776dbd3b3..664656b6cc0 100644
--- a/go/vt/schemadiff/schema.go
+++ b/go/vt/schemadiff/schema.go
@@ -357,6 +357,9 @@ func (s *Schema) normalize() error {
 		if child.Type == "char" && parent.Type == "varchar" {
 			return true
 		}
+		if child.Type == "varchar" && parent.Type == "char" {
+			return true
+		}
 		return false
 	}
 	colTypeEqualForForeignKey := func(child, parent *sqlparser.ColumnType) bool {
diff --git a/go/vt/schemadiff/schema_test.go b/go/vt/schemadiff/schema_test.go
index 05bf6c12df6..22a19b59e68 100644
--- a/go/vt/schemadiff/schema_test.go
+++ b/go/vt/schemadiff/schema_test.go
@@ -383,13 +383,12 @@ func TestInvalidSchema(t *testing.T) {
 			schema: "create table t10(id varchar(50) charset utf8mb4 collate utf8mb4_0900_ai_ci primary key); create table t11 (id int primary key, i varchar(100) charset utf8mb4 collate utf8mb4_0900_ai_ci, key ix(i), constraint f10 foreign key (i) references t10(id) on delete restrict)",
 		},
 		{
-			// weirdly allowed: varchar->char
+			// allowed: varchar->char
 			schema: "create table t10(id varchar(50) charset utf8mb4 collate utf8mb4_0900_ai_ci primary key); create table t11 (id int primary key, i char(100) charset utf8mb4 collate utf8mb4_0900_ai_ci, key ix(i), constraint f10 foreign key (i) references t10(id) on delete restrict)",
 		},
 		{
-			// but weirdly not allowed: char->varchar
-			schema:    "create table t10(id char(50) charset utf8mb4 collate utf8mb4_0900_ai_ci primary key); create table t11 (id int primary key, i varchar(50) charset utf8mb4 collate utf8mb4_0900_ai_ci, key ix(i), constraint f10 foreign key (i) references t10(id) on delete restrict)",
-			expectErr: &ForeignKeyColumnTypeMismatchError{Table: "t11", Constraint: "f10", Column: "i", ReferencedTable: "t10", ReferencedColumn: "id"},
+			// allowed: char->varchar
+			schema: "create table t10(id char(50) charset utf8mb4 collate utf8mb4_0900_ai_ci primary key); create table t11 (id int primary key, i varchar(50) charset utf8mb4 collate utf8mb4_0900_ai_ci, key ix(i), constraint f10 foreign key (i) references t10(id) on delete restrict)",
 		},
 		{
 			schema:    "create table t10(id varchar(50) charset utf8mb3 primary key); create table t11 (id int primary key, i varchar(100) charset utf8mb4, key ix(i), constraint f10 foreign key (i) references t10(id) on delete restrict)",