From 746eb9d7bd29b864461170c43cccaf29f0ebb161 Mon Sep 17 00:00:00 2001
From: Ed Page <eopage@gmail.com>
Date: Mon, 19 Jul 2021 13:42:07 -0500
Subject: [PATCH] fix(derive): Allow partial update of Sub-Subcommands

When using `#[clap(subcommand)]` inside of a Subcommand, we didn't
properly do an `update` but a `from`.

This is a part of #2605
---
 clap_derive/src/derives/subcommand.rs | 14 ++++--
 clap_derive/tests/subcommands.rs      | 64 +++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 3 deletions(-)

diff --git a/clap_derive/src/derives/subcommand.rs b/clap_derive/src/derives/subcommand.rs
index 161e4e44..4b5bdd5d 100644
--- a/clap_derive/src/derives/subcommand.rs
+++ b/clap_derive/src/derives/subcommand.rs
@@ -154,9 +154,17 @@ fn gen_augment(
                         Unit => quote!( #app_var ),
                         Unnamed(FieldsUnnamed { ref unnamed, .. }) if unnamed.len() == 1 => {
                             let ty = &unnamed[0];
-                            quote_spanned! { ty.span()=>
-                                {
-                                    <#ty as clap::Subcommand>::augment_subcommands(#app_var)
+                            if override_required {
+                                quote_spanned! { ty.span()=>
+                                    {
+                                        <#ty as clap::Subcommand>::augment_subcommands_for_update(#app_var)
+                                    }
+                                }
+                            } else {
+                                quote_spanned! { ty.span()=>
+                                    {
+                                        <#ty as clap::Subcommand>::augment_subcommands(#app_var)
+                                    }
                                 }
                             }
                         }
diff --git a/clap_derive/tests/subcommands.rs b/clap_derive/tests/subcommands.rs
index 3464f241..2d909fcf 100644
--- a/clap_derive/tests/subcommands.rs
+++ b/clap_derive/tests/subcommands.rs
@@ -349,3 +349,67 @@ fn update_subcommands() {
     opt.try_update_from(&["test", "command2", "43"]).unwrap();
     assert_eq!(Opt::parse_from(&["test", "command2", "43"]), opt);
 }
+
+#[test]
+fn update_sub_subcommands() {
+    #[derive(Clap, PartialEq, Debug)]
+    enum Opt {
+        #[clap(subcommand)]
+        Child1(Child1),
+        #[clap(subcommand)]
+        Child2(Child2),
+    }
+
+    #[derive(Clap, PartialEq, Debug)]
+    enum Child1 {
+        Command1(Command1),
+        Command2(Command2),
+    }
+
+    #[derive(Clap, PartialEq, Debug)]
+    enum Child2 {
+        Command1(Command1),
+        Command2(Command2),
+    }
+
+    #[derive(Clap, PartialEq, Debug)]
+    struct Command1 {
+        arg1: i32,
+        arg2: i32,
+    }
+
+    #[derive(Clap, PartialEq, Debug)]
+    struct Command2 {
+        arg2: i32,
+    }
+
+    // Full subcommand update
+    let mut opt = Opt::Child1(Child1::Command1(Command1 { arg1: 12, arg2: 14 }));
+    opt.try_update_from(&["test", "child1", "command1", "42", "44"])
+        .unwrap();
+    assert_eq!(
+        Opt::parse_from(&["test", "child1", "command1", "42", "44"]),
+        opt
+    );
+
+    // Partial subcommand update
+    let mut opt = Opt::Child1(Child1::Command1(Command1 { arg1: 12, arg2: 14 }));
+    opt.try_update_from(&["test", "child1", "command1", "42"])
+        .unwrap();
+    assert_eq!(
+        Opt::parse_from(&["test", "child1", "command1", "42", "14"]),
+        opt
+    );
+
+    // Partial subcommand update
+    let mut opt = Opt::Child1(Child1::Command1(Command1 { arg1: 12, arg2: 14 }));
+    opt.try_update_from(&["test", "child1", "command2", "43"])
+        .unwrap();
+    assert_eq!(Opt::parse_from(&["test", "child1", "command2", "43"]), opt);
+
+    // Change subcommand
+    let mut opt = Opt::Child1(Child1::Command1(Command1 { arg1: 12, arg2: 14 }));
+    opt.try_update_from(&["test", "child2", "command2", "43"])
+        .unwrap();
+    assert_eq!(Opt::parse_from(&["test", "child2", "command2", "43"]), opt);
+}