From e0301f124e3138902e8ea1a0df646ee9a4975d32 Mon Sep 17 00:00:00 2001
From: ldm0 <ldm2993593805@163.com>
Date: Sun, 11 Oct 2026 21:59:37 +0800
Subject: [PATCH] feat(webidl): derive sequences of dictionary values

Extracted from wpt-misc-fix.

Source-commit: 4fb35a340e3dd773d2f805c5c4e6bed2e8e71b69
---
 moli-webidl-derive/src/converter.rs      |  1 +
 moli-webidl-derive/src/lib.rs            |  1 +
 moli-webidl/tests/dictionary_sequence.rs | 54 ++++++++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 moli-webidl/tests/dictionary_sequence.rs

diff --git a/moli-webidl-derive/src/converter.rs b/moli-webidl-derive/src/converter.rs
index 2f926bbb27..3498440c09 100644
--- a/moli-webidl-derive/src/converter.rs
+++ b/moli-webidl-derive/src/converter.rs
@@ -66,6 +66,7 @@ impl ConverterKind {
             "unrestricted_double" => Ok(Self::UnrestrictedDouble),
             "boolean" => Ok(Self::Boolean),
             "enum" => Ok(Self::Enum),
+            "dictionary" => Ok(Self::Dictionary),
             "raw" => Ok(Self::Raw),
             _ => Err(Error::new(value.span(), "unsupported converter kind")),
         }
diff --git a/moli-webidl-derive/src/lib.rs b/moli-webidl-derive/src/lib.rs
index e9f7e0ccb6..8f82373567 100644
--- a/moli-webidl-derive/src/lib.rs
+++ b/moli-webidl-derive/src/lib.rs
@@ -20,6 +20,7 @@ use syn::{DeriveInput, parse_macro_input};
 /// values parse an empty dictionary; optional fields skip missing/undefined.
 /// `#[webidl(sequence)]` converts one iterable to `Vec<T>`, using inferred or
 /// explicit item conversion, including `interface` and `brand_check` metadata.
+/// `sequence, converter = "dictionary"` converts each item as a dictionary.
 #[proc_macro_derive(WebIdlArgs, attributes(webidl))]
 pub fn derive_webidl_args(input: TokenStream) -> TokenStream {
     match expand::expand_webidl_args(parse_macro_input!(input as DeriveInput)) {
diff --git a/moli-webidl/tests/dictionary_sequence.rs b/moli-webidl/tests/dictionary_sequence.rs
new file mode 100644
index 0000000000..0a4c273c92
--- /dev/null
+++ b/moli-webidl/tests/dictionary_sequence.rs
@@ -0,0 +1,54 @@
+use moli_webidl::{Context, WebIdlDictionary};
+
+#[derive(WebIdlDictionary)]
+#[webidl(prefix = "Plane")]
+struct Plane {
+    #[webidl(required)]
+    offset: u32,
+}
+#[derive(WebIdlDictionary)]
+#[webidl(prefix = "Planes")]
+struct Planes {
+    #[webidl(sequence, converter = "dictionary")]
+    layout: Option<Vec<Plane>>,
+}
+#[test]
+fn sequence_dictionary_conversion_observes_iteration_and_required_members() {
+    moli_v8_test_util::ensure_v8();
+    let mut isolate = v8::Isolate::new(Default::default());
+    v8::scope!(let scope, &mut isolate);
+    let context = v8::Context::new(scope, Default::default());
+    let scope = &mut v8::ContextScope::new(scope, context);
+    for (source, expected) in [
+        ("({layout:[{offset:3},{offset:7}]})", Some(vec![3, 7])),
+        ("({layout:[]})", Some(vec![])),
+        ("({})", None),
+    ] {
+        let source = v8::String::new(scope, source).unwrap();
+        let value = v8::Script::compile(scope, source, None)
+            .unwrap()
+            .run(scope)
+            .unwrap();
+        let planes =
+            moli_webidl::parse_dictionary::<Planes>(scope, value, Context::argument("Test", 1))
+                .unwrap()
+                .unwrap();
+        assert_eq!(
+            planes
+                .layout
+                .map(|list| list.into_iter().map(|p| p.offset).collect::<Vec<_>>()),
+            expected
+        );
+    }
+    for source in ["({layout:[null]})", "({layout:[{}]})", "({layout:{}})"] {
+        let source = v8::String::new(scope, source).unwrap();
+        let value = v8::Script::compile(scope, source, None)
+            .unwrap()
+            .run(scope)
+            .unwrap();
+        assert!(
+            moli_webidl::parse_dictionary::<Planes>(scope, value, Context::argument("Test", 1))
+                .is_err()
+        );
+    }
+}