From cccc7561f9dc3c90f22ad293fceb7b58a67dabea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ad=C3=A1mek?= <banan23@gmail.com>
Date: Thu, 30 Nov 2023 18:51:53 +0100
Subject: [PATCH] fix(schema): improve json default diffing for down migrations

---
 packages/knex/src/schema/SchemaComparator.ts     | 16 ++++++++++++++--
 .../schema-generator/json-diffing.mysql.test.ts  |  7 +++++--
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/packages/knex/src/schema/SchemaComparator.ts b/packages/knex/src/schema/SchemaComparator.ts
index 339d8ca1aae5..dddd13c6743d 100644
--- a/packages/knex/src/schema/SchemaComparator.ts
+++ b/packages/knex/src/schema/SchemaComparator.ts
@@ -566,6 +566,18 @@ export class SchemaComparator {
     return simplify(expr1) !== simplify(expr2);
   }
 
+  parseJsonDefault(defaultValue?: string | null): Dictionary | string | null {
+    if (!defaultValue) {
+      return null;
+    }
+
+    const val = defaultValue
+      .replace(/^(_\w+\\)?'(.*?)\\?'$/, '$2')
+      .replace(/^\(?'(.*?)'\)?$/, '$1');
+
+    return parseJsonSafe(val);
+  }
+
   hasSameDefaultValue(from: Column, to: Column): boolean {
     if (from.default == null || from.default.toString().toLowerCase() === 'null' || from.default.toString().startsWith('nextval(')) {
       return to.default == null || to.default!.toLowerCase() === 'null';
@@ -579,8 +591,8 @@ export class SchemaComparator {
     }
 
     if (to.mappedType instanceof JsonType) {
-      const defaultValueFrom = parseJsonSafe(from.default.replace(/^(_\w+\\)?'(.*?)\\?'$/, '$2'));
-      const defaultValueTo = parseJsonSafe(to.default?.replace(/^\(?'(.*?)'\)?$/, '$1'));
+      const defaultValueFrom = this.parseJsonDefault(from.default);
+      const defaultValueTo = this.parseJsonDefault(to.default);
 
       return Utils.equals(defaultValueFrom, defaultValueTo);
     }
diff --git a/tests/features/schema-generator/json-diffing.mysql.test.ts b/tests/features/schema-generator/json-diffing.mysql.test.ts
index 131d242ddd2b..89ace188865b 100644
--- a/tests/features/schema-generator/json-diffing.mysql.test.ts
+++ b/tests/features/schema-generator/json-diffing.mysql.test.ts
@@ -29,6 +29,9 @@ beforeAll(async () => {
 afterAll(() => orm.close(true));
 
 test('default values on json columns', async () => {
-  const diff1 = await orm.schema.getUpdateSchemaSQL({ wrap: false });
-  expect(diff1).toBe('');
+  const diff1 = await orm.schema.getUpdateSchemaMigrationSQL({ wrap: false });
+  expect(diff1).toEqual({
+    up: '',
+    down: '',
+  });
 });