From 374ec7055fb30d8ddbbc28a93f6c3f8b42b6544c Mon Sep 17 00:00:00 2001
From: Gabriel de Perthuis <g2p.code@gmail.com>
Date: Sun, 17 Sep 2023 14:36:46 +0200
Subject: [PATCH] Allow default values for absent server_fn arguments

This allows form submission with checkbox inputs to work.
For example:

    let doit = create_server_action::<DoItSFn>();
    <ActionForm action=doit>
      <input type="checkbox" name="is_good" value="true"/>
      <input type="submit"/>
    </ActionForm>

    #[server(DoItSFn, "/api")]
    pub async fn doit(is_good: bool) -> Result<(), ServerFnError> {}

Arguments absent in the request to the server API will use the Default::default() constructor.
---
 server_fn_macro/src/lib.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/server_fn_macro/src/lib.rs b/server_fn_macro/src/lib.rs
index 4e0c6b7c91..f5b43e7f9a 100644
--- a/server_fn_macro/src/lib.rs
+++ b/server_fn_macro/src/lib.rs
@@ -110,7 +110,10 @@ pub fn server_macro_impl(
                 }
                 FnArg::Typed(t) => t,
             };
-            quote! { pub #typed_arg }
+            quote! {
+                #[serde(default)]
+                pub #typed_arg
+            }
         });
 
     let cx_arg = body.inputs.iter().next().and_then(|f| {