fix: resolve issue on index naming strategy

src/naming-strategy/DefaultNamingStrategy.ts

@@ -122,12 +122,9 @@ export class DefaultNamingStrategy implements NamingStrategyInterface {
         columnNames: string[],
         where?: string,
     ): string {
-        // sort incoming column names to avoid issue when ["id", "name"] and ["name", "id"] arrays
-        const clonedColumnNames = [...columnNames]
-        clonedColumnNames.sort()
         const tableName = this.getTableName(tableOrName)
         const replacedTableName = tableName.replace(".", "_")
-        let key = `${replacedTableName}_${clonedColumnNames.join("_")}`
+        let key = `${replacedTableName}_${columnNames.join("_")}`
         if (where) key += `_${where}`
 
         return "IDX_" + RandomGenerator.sha1(key).substr(0, 26)

test/github-issues/10856/entity/user.ts

@@ -0,0 +1,17 @@
+import { Column, Entity, Index, PrimaryGeneratedColumn } from "../../../../src"
+
+@Entity({
+    name: "user",
+})
+@Index(["firstName", "lastName"])
+@Index(["lastName", "firstName"])
+export class User {
+    @PrimaryGeneratedColumn()
+    id: number
+
+    @Column({ nullable: true })
+    firstName: string
+
+    @Column()
+    lastName: string
+}

test/github-issues/10856/issue-10856.ts

@@ -0,0 +1,36 @@
+import "reflect-metadata"
+import {
+    createTestingConnections,
+    closeTestingConnections,
+} from "../../utils/test-utils"
+import { DataSource } from "../../../src/index.js"
+import { expect } from "chai"
+
+describe("github issues > #10856 TypeORM Migration Bug: Duplicate Index Names in Generated Migration", () => {
+    let dataSources: DataSource[]
+
+    before(
+        async () =>
+            (dataSources = await createTestingConnections({
+                entities: [__dirname + "/entity/*{.js,.ts}"],
+                schemaCreate: true,
+                dropSchema: true,
+                enabledDrivers: ["mysql"],
+                logging: false,
+            })),
+    )
+
+    after(() => closeTestingConnections(dataSources))
+
+    it("Indexes on same column but different order generate a indexes with different names", () =>
+        Promise.all(
+            dataSources.map(async (dataSource) => {
+                const queryRunner = dataSource.createQueryRunner()
+                const schema = await queryRunner.getTable("user")
+                await queryRunner.release()
+                expect(schema!.indices[0].name).should.be.not.equal(
+                    schema!.indices[1].name,
+                )
+            }),
+        ))
+})