fix boolean handling

__tests__/stubs/core/core.test.ts

@@ -291,13 +291,37 @@ describe('Core', () => {
         expect(getBooleanInput('test')).toEqual(false)
       })
 
+      it('Gets default inputs', () => {
+        delete process.env.INPUT_TEST
+        delete process.env.INPUT_test
+
+        EnvMeta.inputs = {
+          test: {
+            description: 'test',
+            required: true,
+            // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+            // @ts-ignore
+            default: false
+          }
+        }
+
+        expect(getBooleanInput('test')).toEqual(false)
+      })
+
       it('Throws an error if the input is required and not found', () => {
         expect(() =>
           getBooleanInput('test-input-missing', {
             required: true
           })
         ).toThrow()
       })
+      it('Does NOT throws an error if the input is not required and not found', () => {
+        expect(() =>
+          getBooleanInput('test-input-missing', {
+            required: false
+          })
+        ).not.toThrow()
+      })
 
       it('Returns true or false for valid YAML boolean values', () => {
         process.env.INPUT_TEST = 'true'

src/stubs/core/core.ts

@@ -265,7 +265,10 @@ export function getMultilineInput(
  * @param options The options for the input
  * @returns The value of the input
  */
-export function getBooleanInput(name: string, options?: InputOptions): boolean {
+export function getBooleanInput(
+  name: string,
+  options?: InputOptions
+): boolean | undefined {
   // This is effectively a copy of the actual `getInput` function, instead of
   // using proxyquire's `callThru()` option.
 
@@ -278,12 +281,18 @@ export function getBooleanInput(name: string, options?: InputOptions): boolean {
 
   // If the input is not present in the environment variables, it has not been
   // set. In that case, check the default value.
-  if (input === '' && EnvMeta.inputs[name]?.default !== undefined)
-    input = EnvMeta.inputs[name].default.trim()
+  if (input === '' && EnvMeta.inputs[name]?.default !== undefined) {
+    // we call .toString in case its a boolean
+    input = EnvMeta.inputs[name].default.toString().trim()
+  }
 
   // Throw an error if the input is required and not supplied
-  if (options && options.required === true && input === '')
-    throw new Error(`Input required and not supplied: ${name}`)
+  if (input === '')
+    if (options && options.required === true) {
+      throw new Error(`Input required and not supplied: ${name}`)
+    } else {
+      return undefined
+    }
 
   if (['true', 'True', 'TRUE'].includes(input)) return true
   if (['false', 'False', 'FALSE'].includes(input)) return false