fix: @unique constraint is not created with specified name

src/driver/sqlite-abstract/AbstractSqliteQueryRunner.ts

@@ -899,6 +899,17 @@ export abstract class AbstractSqliteQueryRunner extends BaseQueryRunner implemen
                 });
             });
 
+            // find unique constraints from CREATE TABLE sql
+            let uniqueRegexResult;
+            const uniqueMappings: { name: string, columns: string[] }[] = []
+            const uniqueRegex = /CONSTRAINT "([^"]*)" UNIQUE \((.*?)\)/g;
+            while ((uniqueRegexResult = uniqueRegex.exec(sql)) !== null) {
+                uniqueMappings.push({
+                    name: uniqueRegexResult[1],
+                    columns: uniqueRegexResult[2].substr(1, uniqueRegexResult[2].length - 2).split(`", "`)
+                });
+            }
+
             // build unique constraints
             const tableUniquePromises = dbIndices
                 .filter(dbIndex => dbIndex["origin"] === "u")
@@ -919,9 +930,15 @@ export abstract class AbstractSqliteQueryRunner extends BaseQueryRunner implemen
                             column.isUnique = true;
                     }
 
-                    // Sqlite does not store unique constraint name, so we generate its name manually.
+                    // find existent mapping by a column names
+                    const foundMapping = uniqueMappings.find(mapping => {
+                        return mapping!.columns.every(column =>
+                            indexColumns.indexOf(column) !== -1
+                        )
+                    })
+
                     return new TableUnique({
-                        name: this.connection.namingStrategy.uniqueConstraintName(table, indexColumns),
+                        name: foundMapping ? foundMapping.name : this.connection.namingStrategy.uniqueConstraintName(table, indexColumns),
                         columnNames: indexColumns
                     });
                 });

test/github-issues/2376/entity/User.ts

@@ -0,0 +1,19 @@
+import {Column, Entity, PrimaryGeneratedColumn, Unique} from "../../../../src";
+
+@Entity()
+@Unique(["age"])
+@Unique("unique-email", ["email"])
+@Unique("unique-email-nickname", ["email", "nickname"])
+export class User {
+    @PrimaryGeneratedColumn()
+    id: number;
+
+    @Column()
+    email: string;
+
+    @Column()
+    nickname: string;
+
+    @Column()
+    age: number;
+}

test/github-issues/2376/issue-2376.ts

@@ -0,0 +1,35 @@
+import "reflect-metadata";
+import {Connection} from "../../../src";
+import {createTestingConnections, closeTestingConnections} from "../../utils/test-utils";
+import {User} from "./entity/User";
+import {expect} from "chai";
+import {MysqlDriver} from "../../../src/driver/mysql/MysqlDriver";
+
+describe("github issues > #2376 Naming single column unique constraint with decorator not working as expected", () => {
+    let connections: Connection[];
+    before(async () => connections = await createTestingConnections({
+        schemaCreate: true,
+        dropSchema: true,
+        entities: [User],
+    }));
+    after(() => closeTestingConnections(connections));
+
+    it("should keep user-specified Unique constraint name", () => Promise.all(connections.map(async connection => {
+        const queryRunner = connection.createQueryRunner();
+
+        const table = await queryRunner.getTable("user");
+        await queryRunner.release()
+
+        let unique1 = table!.uniques.find(it => it.name === "unique-email");
+        let unique2 = table!.uniques.find(it => it.name === "unique-email-nickname");
+
+        if (connection.driver instanceof MysqlDriver) {
+            unique1 = table!.indices.find(it => it.name === "unique-email");
+            unique2 = table!.indices.find(it => it.name === "unique-email-nickname");
+        }
+
+        expect(unique1).to.be.not.undefined
+        expect(unique2).to.be.not.undefined
+
+    })));
+});