Derive doc clap ordering for multiple Clap

Fix clap-rs#2527

clap_derive/Cargo.toml

@@ -41,6 +41,7 @@ proc-macro-error = "1"
 clap = { path = "../" }
 clap_generate = { path = "../clap_generate" }
 trybuild = "1.0"
+regex = "1.0"
 rustversion = "1"
 version-sync = "0.9"
 

clap_derive/src/derives/into_app.rs

@@ -364,8 +364,8 @@ pub fn gen_app_augmentation(
     let app_methods = parent_attribute.top_level_methods();
     let version = parent_attribute.version();
     quote! {{
-        let #app_var = #app_var#app_methods;
         #( #args )*
+        let #app_var = #app_var#app_methods;
         #subcmd
         #app_var#version
     }}

clap_derive/tests/flatten.rs

@@ -12,7 +12,9 @@
 // commit#ea76fa1b1b273e65e3b0b1046643715b49bec51f which is licensed under the
 // MIT/Apache 2.0 license.
 
-use clap::Clap;
+mod utils;
+
+use clap::{Clap, IntoApp};
 
 #[test]
 fn flatten() {
@@ -160,3 +162,40 @@ fn update_subcommands_with_flatten() {
     opt.update_from(&["test", "command2", "43"]);
     assert_eq!(Opt::parse_from(&["test", "command2", "43"]), opt);
 }
+
+#[test]
+fn docstrings_ordering_with_multiple_clap() {
+    /// this is the docstring for Flattened
+    #[derive(Clap)]
+    struct Flattened {
+        #[clap(long)]
+        foo: bool,
+    }
+
+    /// this is the docstring for Command
+    #[derive(Clap)]
+    struct Command {
+        #[clap(flatten)]
+        flattened: Flattened,
+    }
+
+    static ISSUE_2527: &str = "clap_derive 
+
+this is the docstring for Command
+
+USAGE:
+    command [FLAGS]
+
+FLAGS:
+        --foo        
+    -h, --help       Prints help information
+    -V, --version    Prints version information
+";
+
+    assert!(utils::compare_output(
+        Command::into_app(),
+        "command --help",
+        ISSUE_2527,
+        false
+    ));
+}

clap_derive/tests/utils.rs

@@ -5,7 +5,11 @@
 // Accept and endure. Do not touch.
 #![allow(unused)]
 
-use clap::IntoApp;
+use std::io::{Cursor, Write};
+
+use regex::Regex;
+
+use clap::{App, IntoApp};
 
 pub fn get_help<T: IntoApp>() -> String {
     let mut output = Vec::new();
@@ -52,3 +56,43 @@ pub fn get_subcommand_long_help<T: IntoApp>(subcmd: &str) -> String {
 
     output
 }
+
+fn compare<S, S2>(l: S, r: S2) -> bool
+where
+    S: AsRef<str>,
+    S2: AsRef<str>,
+{
+    let re = Regex::new("\x1b[^m]*m").unwrap();
+    // Strip out any mismatching \r character on windows that might sneak in on either side
+    let ls = l.as_ref().trim().replace("\r", "");
+    let rs = r.as_ref().trim().replace("\r", "");
+    let left = re.replace_all(&*ls, "");
+    let right = re.replace_all(&*rs, "");
+    let b = left == right;
+    if !b {
+        println!();
+        println!("--> left");
+        println!("{}", left);
+        println!("--> right");
+        println!("{}", right);
+        println!("--")
+    }
+    b
+}
+
+pub fn compare_output(l: App, args: &str, right: &str, stderr: bool) -> bool {
+    let mut buf = Cursor::new(Vec::with_capacity(50));
+    let res = l.try_get_matches_from(args.split(' ').collect::<Vec<_>>());
+    let err = res.unwrap_err();
+    write!(&mut buf, "{}", err).unwrap();
+    let content = buf.into_inner();
+    let left = String::from_utf8(content).unwrap();
+    assert_eq!(
+        stderr,
+        err.use_stderr(),
+        "Should Use STDERR failed. Should be {} but is {}",
+        stderr,
+        err.use_stderr()
+    );
+    compare(left, right)
+}