fix: mix of parsed and non-parsed option names getting default value

src/CAC.ts

@@ -220,7 +220,11 @@ class CAC extends EventEmitter {
       this.unsetMatchedCommand()
     }
 
-    if (this.options.version && this.showVersionOnExit && this.matchedCommandName == null) {
+    if (
+      this.options.version &&
+      this.showVersionOnExit &&
+      this.matchedCommandName == null
+    ) {
       this.outputVersion()
       run = false
       this.unsetMatchedCommand()
@@ -285,8 +289,14 @@ class CAC extends EventEmitter {
 
     for (const cliOption of cliOptions) {
       if (!ignoreDefault && cliOption.config.default !== undefined) {
-        for (const name of cliOption.names) {
-          options[name] = cliOption.config.default
+        // apply default value only if none of the names was parsed
+        const parsedOptionNames = cliOption.names.filter(
+          (name: PropertyKey) => parsed[name] !== undefined
+        )
+        if (parsedOptionNames.length === 0) {
+          for (const name of cliOption.names) {
+            options[name] = cliOption.config.default
+          }
         }
       }
 

src/__test__/index.test.ts

@@ -81,6 +81,71 @@ test('double dashes', () => {
   expect(options['--']).toEqual(['npm', 'test'])
 })
 
+test('default value for option', () => {
+  const cli = cac()
+
+  cli.option('-b, --base-url <baseUrl>', 'Set the instance URL', {
+    default: 'https://github.com',
+  })
+
+  const { options } = cli.parse(`node bin`.split(' '))
+
+  expect(options).toEqual({
+    '--': [],
+    b: 'https://github.com',
+    baseUrl: 'https://github.com',
+  })
+})
+
+test('default value for option names 1', () => {
+  const cli = cac()
+
+  cli.option('-b, --base-url <baseUrl>', 'Set the instance URL', {
+    default: 'https://github.com',
+  })
+
+  let { options } = cli.parse(`node bin -b https://gitlab.com`.split(' '))
+
+  expect(options).toEqual({
+    '--': [],
+    b: 'https://gitlab.com',
+    baseUrl: 'https://gitlab.com',
+  })
+})
+
+test('default value for option names 2', () => {
+  const cli = cac()
+
+  cli.option('-b, --base-url <baseUrl>', 'Set the instance URL', {
+    default: 'https://github.com',
+  })
+
+  let { options } = cli.parse(
+    `node bin --base-url https://gitlab.com`.split(' ')
+  )
+
+  expect(options).toEqual({
+    '--': [],
+    baseUrl: 'https://gitlab.com',
+  })
+})
+
+test('default value for option names 3', () => {
+  const cli = cac()
+
+  cli.option('-s, --skip', 'Skip process', {
+    default: false,
+  })
+
+  const { options } = cli.parse(`node bin`.split(' '))
+
+  expect(options).toEqual({
+    '--': [],
+    s: false,
+    skip: false,
+  })
+})
+
 test('default value for negated option', () => {
   const cli = cac()