From 733784804d0df1a99be675dece07ff3c156746b4 Mon Sep 17 00:00:00 2001
From: Taylor Baldwin <taylorbaldwin@gmail.com>
Date: Thu, 14 Jul 2022 12:11:16 -0400
Subject: [PATCH] fix bug where custom flags have multiple=false (#414)

Co-authored-by: Mike Donnalley <mdonnalley@salesforce.com>
---
 src/parser/flags.ts       | 2 +-
 test/parser/parse.test.ts | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/parser/flags.ts b/src/parser/flags.ts
index 286e06ea3..b6bdc8d40 100644
--- a/src/parser/flags.ts
+++ b/src/parser/flags.ts
@@ -18,7 +18,7 @@ export function build<T>(defaults: Partial<OptionFlag<T>>): Definition<T> {
       ...defaults,
       ...options,
       input: [] as string[],
-      multiple: Boolean(options.multiple),
+      multiple: Boolean(options.multiple === undefined ? defaults.multiple : options.multiple),
       type: 'option',
     } as any
   }
diff --git a/test/parser/parse.test.ts b/test/parser/parse.test.ts
index b705a033d..0fc6d48ef 100644
--- a/test/parser/parse.test.ts
+++ b/test/parser/parse.test.ts
@@ -327,6 +327,14 @@ See more help with --help`)
         expect(out.flags.baz.toUpperCase()).to.equal('D')
         expect(out.flags.bar.join('|')).to.equal('a|b')
       })
+      it('parses multiple flags on custom flags', async () => {
+        const out = await parse(['--foo', 'a', '--foo=b'], {
+          flags: {
+            foo: flags.option({multiple: true, parse: async i => i}),
+          },
+        })
+        expect(out.flags).to.deep.include({foo: ['a', 'b']})
+      })
     })
 
     describe('strict: false', () => {