fix: Unnecessary migrations for unsigned numeric types

In MariaDB, unsigned numeric types (``<tiny,small,medium>int`) without an explicit `width` property set would generate migrations on every run. This is due to an error in setting the default width for unsigned types.

Fixes typeorm#2943

src/driver/mysql/MysqlQueryRunner.ts

@@ -1296,6 +1296,7 @@ export class MysqlQueryRunner extends BaseQueryRunner implements QueryRunner {
                     tableColumn.name = dbColumn["COLUMN_NAME"];
                     tableColumn.type = dbColumn["DATA_TYPE"].toLowerCase();
 
+                    tableColumn.unsigned = tableColumn.zerofill ? true : dbColumn["COLUMN_TYPE"].indexOf("unsigned") !== -1;
                     if (this.driver.withWidthColumnTypes.indexOf(tableColumn.type as ColumnType) !== -1) {
                         const width = dbColumn["COLUMN_TYPE"].substring(dbColumn["COLUMN_TYPE"].indexOf("(") + 1, dbColumn["COLUMN_TYPE"].indexOf(")"));
                         tableColumn.width = width && !this.isDefaultColumnWidth(table, tableColumn, parseInt(width)) ? parseInt(width) : undefined;
@@ -1333,7 +1334,6 @@ export class MysqlQueryRunner extends BaseQueryRunner implements QueryRunner {
                         return this.driver.buildTableName(dbPrimaryKey["TABLE_NAME"], undefined, dbPrimaryKey["TABLE_SCHEMA"]) === tableFullName && dbPrimaryKey["COLUMN_NAME"] === tableColumn.name;
                     });
                     tableColumn.zerofill = dbColumn["COLUMN_TYPE"].indexOf("zerofill") !== -1;
-                    tableColumn.unsigned = tableColumn.zerofill ? true : dbColumn["COLUMN_TYPE"].indexOf("unsigned") !== -1;
                     tableColumn.isGenerated = dbColumn["EXTRA"].indexOf("auto_increment") !== -1;
                     if (tableColumn.isGenerated)
                         tableColumn.generationStrategy = "increment";

src/query-runner/BaseQueryRunner.ts

@@ -324,10 +324,18 @@ export abstract class BaseQueryRunner {
                 return false;
         }
 
-        if (this.connection.driver.dataTypeDefaults
+        const defaultWidthForType = this.connection.driver.dataTypeDefaults
             && this.connection.driver.dataTypeDefaults[column.type]
-            && this.connection.driver.dataTypeDefaults[column.type].width) {
-            return this.connection.driver.dataTypeDefaults[column.type].width === width;
+            && this.connection.driver.dataTypeDefaults[column.type].width;
+
+        if (defaultWidthForType) {
+            // the default widths of these numeric types are 1 less when the column is unsigned.
+            const typesWithReducedUnsignedDefault = ["int", "tinyint", "smallint", "mediumint"];
+            if (column.unsigned && -1 < typesWithReducedUnsignedDefault.indexOf(column.type)) {
+                return (defaultWidthForType - 1) === width;
+            } else {
+                return defaultWidthForType === width;
+            }
         }
 
         return false;

test/github-issues/2943/entity/Test.ts

@@ -0,0 +1,22 @@
+import { Column, Entity, PrimaryColumn } from "../../../../src";
+
+@Entity()
+export class Test {
+    @PrimaryColumn()
+    id: number;
+
+    @Column({ type: 'int', unsigned: true})
+    uInt: number;
+
+    @Column({ type: 'tinyint', unsigned: true})
+    uTinyInt: number;
+
+    @Column({ type: 'smallint', unsigned: true})
+    uSmallInt: number;
+
+    @Column({ type: 'mediumint', unsigned: true})
+    uMediumInt: number;
+
+    @Column({ type: 'bigint', unsigned: true})
+    uBigInt: number;
+}

test/github-issues/2943/issue-2943.ts

@@ -0,0 +1,28 @@
+import "reflect-metadata";
+import { expect } from "chai";
+import { Connection } from "../../../src";
+import { closeTestingConnections, createTestingConnections, reloadTestingDatabases } from "../../utils/test-utils";
+import { Test } from "./entity/Test";
+
+describe.only("github issues > #2932 Inappropriate migration generated", () => {
+
+    let connections: Connection[];
+
+    before(async () => {
+        connections = await createTestingConnections({
+            entities: [Test],
+            schemaCreate: true,
+            dropSchema: true
+        });
+    });
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should not create migrations for unsigned numeric types with no specified width", () =>
+        Promise.all(connections.map(async (connection) => {
+            const sqlInMemory = await connection.driver.createSchemaBuilder().log();
+
+            expect(sqlInMemory.upQueries).to.eql([]);
+            expect(sqlInMemory.upQueries.length).to.eq(0);
+        })));
+});