v0.3.20

CHANGELOG.md

@@ -1,3 +1,8 @@
+# v0.3.20 (2020-10-12)
+
+* Fixed [a breakage](https://github.com/TeXitoi/structopt/issues/439)
+  when the struct is placed inside a `macro_rules!` macro.
+
 # v0.3.19 (2020-10-08)
 
 * Added [StructOpt::from_args_safe](https://docs.rs/structopt/0.3/structopt/trait.StructOpt.html#tymethod.from_args_safe) as a shortcut for `StructOpt::from_iter_safe(std::env::args_os())`.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "structopt"
-version = "0.3.19"
+version = "0.3.20"
 edition = "2018"
 authors = ["Guillaume Pinot <texitoi@texitoi.eu>", "others"]
 description = "Parse command line argument by defining a struct."
@@ -28,7 +28,7 @@ travis-ci = { repository = "TeXitoi/structopt" }
 
 [dependencies]
 clap = { version = "2.33", default-features = false }
-structopt-derive = { path = "structopt-derive", version = "=0.4.12" }
+structopt-derive = { path = "structopt-derive", version = "=0.4.13" }
 lazy_static = "1.4.0"
 paw_dep = { version = "1", optional = true, package = "paw" }
 

structopt-derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "structopt-derive"
-version = "0.4.12"
+version = "0.4.13"
 edition = "2018"
 authors = ["Guillaume Pinot <texitoi@texitoi.eu>"]
 description = "Parse command line argument by defining a struct, derive crate."

structopt-derive/src/lib.rs

@@ -11,6 +11,8 @@
 //! for the usage of `#[derive(StructOpt)]`.
 
 #![allow(clippy::large_enum_variant)]
+// FIXME: remove when and if our MSRV hits 1.42
+#![allow(clippy::match_like_matches_macro)]
 #![forbid(unsafe_code)]
 
 extern crate proc_macro;

structopt-derive/src/ty.rs

@@ -63,6 +63,8 @@ fn subty_if<F>(ty: &syn::Type, f: F) -> Option<&syn::Type>
 where
     F: FnOnce(&PathSegment) -> bool,
 {
+    let ty = strip_group(ty);
+
     only_last_segment(ty)
         .filter(|segment| f(segment))
         .and_then(|segment| {
@@ -85,6 +87,8 @@ pub fn subty_if_name<'a>(ty: &'a syn::Type, name: &str) -> Option<&'a syn::Type>
 }
 
 pub fn is_simple_ty(ty: &syn::Type, name: &str) -> bool {
+    let ty = strip_group(ty);
+
     only_last_segment(ty)
         .map(|segment| {
             if let PathArguments::None = segment.arguments {
@@ -96,6 +100,23 @@ pub fn is_simple_ty(ty: &syn::Type, name: &str) -> bool {
         .unwrap_or(false)
 }
 
+// If the struct is placed inside of a macro_rules! declaration,
+// in some circumstances, the tokens inside will be enclosed
+// in `proc_macro::Group` delimited by invisible `proc_macro::Delimiter::None`.
+//
+// In syn speak, this is encoded via `*::Group` variants. We don't really care about
+// that, so let's just strip it.
+//
+// Details: https://doc.rust-lang.org/proc_macro/enum.Delimiter.html#variant.None
+// See also: https://github.com/TeXitoi/structopt/issues/439
+fn strip_group(mut ty: &syn::Type) -> &syn::Type {
+    while let Type::Group(group) = ty {
+        ty = &*group.elem;
+    }
+
+    ty
+}
+
 fn is_generic_ty(ty: &syn::Type, name: &str) -> bool {
     subty_if_name(ty, name).is_some()
 }

tests/regressions.rs

@@ -0,0 +1,25 @@
+use structopt::StructOpt;
+
+mod utils;
+use utils::*;
+
+#[test]
+fn invisible_group_issue_439() {
+    macro_rules! m {
+        ($bool:ty) => {
+            #[derive(Debug, StructOpt)]
+            struct Opts {
+                #[structopt(long = "x")]
+                x: $bool,
+            }
+        };
+    }
+
+    m!(bool);
+
+    let help = get_long_help::<Opts>();
+
+    assert!(help.contains("--x"));
+    assert!(!help.contains("--x <x>"));
+    Opts::from_iter_safe(&["test", "--x"]).unwrap();
+}