add ability to parse additional group methods

clap_derive/src/derives/args.rs

@@ -400,10 +400,13 @@ pub fn gen_augment(
             }};
         }
 
+        let group_methods = parent_item.group_methods();
+
         quote!(
             .group(
                 clap::ArgGroup::new(#group_id)
                     .multiple(true)
+                    #group_methods
                     .args(#literal_group_members)
             )
         )

clap_derive/src/item.rs

@@ -49,6 +49,7 @@ pub struct Item {
     is_enum: bool,
     is_positional: bool,
     skip_group: bool,
+    group_methods: Vec<Method>,
     kind: Sp<Kind>,
 }
 
@@ -273,6 +274,7 @@ impl Item {
             is_enum: false,
             is_positional: true,
             skip_group: false,
+            group_methods: vec![],
             kind,
         }
     }
@@ -325,7 +327,10 @@ impl Item {
             if name == "short" || name == "long" {
                 self.is_positional = false;
             }
-            self.methods.push(Method::new(name, quote!(#arg)));
+            match kind {
+                AttrKind::Group => self.group_methods.push(Method::new(name, quote!(#arg))),
+                _ => self.methods.push(Method::new(name, quote!(#arg))),
+            };
         }
     }
 
@@ -964,6 +969,11 @@ impl Item {
         quote!( #(#doc_comment)* #(#methods)* )
     }
 
+    pub fn group_methods(&self) -> TokenStream {
+        let group_methods = &self.group_methods;
+        quote!( #(#group_methods)* )
+    }
+
     pub fn deprecations(&self) -> proc_macro2::TokenStream {
         let deprecations = &self.deprecations;
         quote!( #(#deprecations)* )

tests/derive/groups.rs

@@ -120,3 +120,48 @@ fn helpful_panic_on_duplicate_groups() {
     use clap::CommandFactory;
     Opt::command().debug_assert();
 }
+
+#[test]
+fn required_group() {
+    #[derive(Parser, Debug)]
+    struct Opt {
+        #[command(flatten)]
+        source: Source,
+
+        #[arg(long)]
+        alt_source: String,
+    }
+
+    #[derive(clap::Args, Debug)]
+    #[group(required = true, multiple = false, conflicts_with = "alt_source")]
+    struct Source {
+        #[arg(long)]
+        path: Option<std::path::PathBuf>,
+        #[arg(long)]
+        git: Option<String>,
+    }
+
+    const OUTPUT: &str = "\
+error: the following required arguments were not provided:
+  --alt-source <ALT_SOURCE>
+  <--path <PATH>|--git <GIT>>
+
+Usage: prog --alt-source <ALT_SOURCE> <--path <PATH>|--git <GIT>>
+
+For more information, try '--help'.
+";
+    assert_output::<Opt>("prog", OUTPUT, true);
+
+    use clap::Args;
+    assert_eq!(Opt::group_id(), Some(clap::Id::from("Opt")));
+    assert_eq!(Source::group_id(), Some(clap::Id::from("Source")));
+    use clap::CommandFactory;
+    let source_id = clap::Id::from("Source");
+    let opt_command = Opt::command();
+    let source_group = opt_command
+        .get_groups()
+        .find(|g| g.get_id() == &source_id)
+        .unwrap();
+    assert!(source_group.is_required_set());
+    // assert!(source_group.is_multiple()); currently broken. Fixed by PR #4704
+}

tests/derive_ui/group_name_attribute.rs

@@ -0,0 +1,23 @@
+use clap::Parser;
+
+#[derive(Parser, Debug)]
+#[command(name = "basic", subcommand)]
+struct Opt {
+    #[command(flatten)]
+    source: Source,
+}
+
+#[derive(clap::Args, Debug)]
+#[group(required = true, name = "src")]
+struct Source {
+    #[arg(short)]
+    git: String,
+
+    #[arg(short)]
+    path: String,
+}
+
+fn main() {
+    let opt = Opt::parse();
+    println!("{:?}", opt);
+}

tests/derive_ui/group_name_attribute.stderr

@@ -0,0 +1,7 @@
+error: `#[group(required = true, name = "src")]` does not support name
+ --> $DIR/group_name_attribute.rs:3:10
+   |
+11 |#[group(required = true, name = "src")]
+   |                         ^^^^^^^^^^^^
+   |
+  = note: this error originates in the derive macro `group` (in Nightly builds, run with -Z macro-backtrace for more info)