From 2f05199f02e67cb7b8e820058ca522cb3128f6e8 Mon Sep 17 00:00:00 2001
From: weifanglab <weifanglab@outlook.com>
Date: Tue, 7 Jul 2026 15:55:42 +0800
Subject: [PATCH] Fix HexString JSON schema for empty byte strings

Signed-off-by: weifanglab <weifanglab@outlook.com>
---
 .../rollup-interface/src/common/hex_string.rs | 21 +++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/crates/rollup-interface/src/common/hex_string.rs b/crates/rollup-interface/src/common/hex_string.rs
index 1f07b7834e..885e397213 100644
--- a/crates/rollup-interface/src/common/hex_string.rs
+++ b/crates/rollup-interface/src/common/hex_string.rs
@@ -33,8 +33,8 @@ impl schemars::JsonSchema for HexString {
     fn json_schema(_gen: &mut schemars::SchemaGenerator) -> schemars::Schema {
         schemars::json_schema!({
             "type": "string",
-            "pattern": "^0x(?:[a-fA-F0-9]{2})+$",
-            "description": "A `0x`-prefixed hexadecimal string (uppercase or lowercase) of variable length, with an even number of hex digits.",
+            "pattern": "^0x(?:[a-fA-F0-9]{2})*$",
+            "description": "A `0x`-prefixed hexadecimal string (uppercase or lowercase) of variable length, including zero bytes, with an even number of hex digits.",
         })
     }
 }
@@ -273,4 +273,21 @@ mod tests {
     fn hex_string_str_roundtrip(item: HexString) {
         test_str_roundtrip(item);
     }
+
+    #[test]
+    fn variable_length_hex_string_json_schema_allows_empty_string() {
+        let empty_hex = HexString(Vec::<u8>::new());
+
+        assert_eq!(serde_json::to_string(&empty_hex).unwrap(), "\"0x\"");
+        assert_eq!(
+            HexString::<Vec<u8>>::from_str("0x").unwrap(),
+            HexString(Vec::new())
+        );
+
+        let mut schema_generator = schemars::SchemaGenerator::default();
+        let schema = <HexString as schemars::JsonSchema>::json_schema(&mut schema_generator);
+        let schema = serde_json::to_value(schema).unwrap();
+
+        assert_eq!(schema["pattern"], "^0x(?:[a-fA-F0-9]{2})*$");
+    }
 }