Fix withDefault type helper to work with boolean

`withDefault` is a type helper that allows to create a type that
defaults to a default value when trying to decode a nullish value.
That type was not correctly working with boolean types, causing `false`
values to be replaced by true. This would specifically cause issues when
parsing the target state, where a `running: false` in a service would
become a `running: true` due to the type decoding.

Change-type: patch

src/types/state.ts

@@ -123,17 +123,16 @@ export type DeviceState = {
 };
 
 // Return a type with a default value
-const withDefault = <T extends t.Any>(
+export const withDefault = <T extends t.Any>(
 	type: T,
 	defaultValue: t.TypeOf<T>,
 ): t.Type<t.TypeOf<T>> =>
 	new t.Type(
 		type.name,
 		type.is,
-		(v, c) => type.validate(!!v ? v : defaultValue, c),
+		(v, c) => type.validate(v != null ? v : defaultValue, c),
 		type.encode,
 	);
-
 /**
  * Utility function to return a io-ts type from a native typescript
  * type.

test/unit/lib/validation.spec.ts

@@ -286,33 +286,54 @@ describe('validation', () => {
 				'accepts apps with no services',
 			).to.be.true;
 
-			expect(
-				isRight(
-					TargetApps.decode({
-						abcd: {
-							id: 1234,
-							name: 'something',
-							releases: {
-								bar: {
-									id: 123,
-									services: {
-										bazbaz: {
-											id: 45,
-											image_id: 34,
-											image: 'foo',
-											environment: { MY_SERVICE_ENV_VAR: '123' },
-											labels: { 'io.balena.features.supervisor-api': 'true' },
-										},
-									},
-									volumes: {},
-									networks: {},
+			const target = TargetApps.decode({
+				abcd: {
+					id: 1234,
+					name: 'something',
+					releases: {
+						bar: {
+							id: 123,
+							services: {
+								bazbaz: {
+									id: 45,
+									image_id: 34,
+									image: 'foo',
+									environment: { MY_SERVICE_ENV_VAR: '123' },
+									labels: { 'io.balena.features.supervisor-api': 'true' },
+									running: false,
 								},
 							},
+							volumes: {},
+							networks: {},
 						},
-					}),
-				),
-				'accepts apps with a service',
-			).to.be.true;
+					},
+				},
+			});
+			expect(isRight(target), 'accepts apps with a service').to.be.true;
+			expect((target as any).right).to.deep.equal({
+				abcd: {
+					id: 1234,
+					name: 'something',
+					class: 'fleet',
+					releases: {
+						bar: {
+							id: 123,
+							services: {
+								bazbaz: {
+									id: 45,
+									image_id: 34,
+									image: 'foo',
+									environment: { MY_SERVICE_ENV_VAR: '123' },
+									labels: { 'io.balena.features.supervisor-api': 'true' },
+									running: false,
+								},
+							},
+							volumes: {},
+							networks: {},
+						},
+					},
+				},
+			});
 		});
 
 		it('rejects app with invalid environment', () => {

test/unit/types.spec.ts

@@ -0,0 +1,42 @@
+import { expect } from 'chai';
+import * as t from 'io-ts';
+
+import { withDefault } from '~/src/types';
+
+describe('types', () => {
+	describe('withDefault', () => {
+		it('decodes object values', () => {
+			expect(withDefault(t.record(t.string, t.string), {}).decode(undefined))
+				.to.have.property('right')
+				.that.deep.equals({});
+
+			expect(withDefault(t.record(t.string, t.string), {}).decode(null))
+				.to.have.property('right')
+				.that.deep.equals({});
+
+			expect(withDefault(t.record(t.string, t.string), {}).decode({}))
+				.to.have.property('right')
+				.that.deep.equals({});
+
+			expect(
+				withDefault(t.record(t.string, t.string), {}).decode({ dummy: 'yes' }),
+			)
+				.to.have.property('right')
+				.that.deep.equals({ dummy: 'yes' });
+		});
+
+		it('decodes boolean values', () => {
+			expect(withDefault(t.boolean, true).decode(undefined))
+				.to.have.property('right')
+				.that.equals(true);
+
+			expect(withDefault(t.boolean, true).decode(null))
+				.to.have.property('right')
+				.that.equals(true);
+
+			expect(withDefault(t.boolean, true).decode(false))
+				.to.have.property('right')
+				.that.equals(false);
+		});
+	});
+});