[taplo-common] fix infinite recursion with composed allOfs

crates/taplo-common/Cargo.toml

@@ -59,6 +59,12 @@ tokio = { version = "1.24.2", features = [
   "io-util",
 ], default-features = false }
 
+[dev-dependencies]
+tokio = { version = "1.24.2", features = [
+  "macros",
+  "test-util",
+] }
+
 [features]
 # default-tls enables native-tls but without enabling native-tls specific features.
 native-tls = ["reqwest/default-tls"]

crates/taplo-common/src/schema/mod.rs

@@ -543,9 +543,12 @@ impl<E: Environment> Schemas<E> {
         if let Some(all_ofs) = schema["allOf"].as_array() {
             if !all_ofs.is_empty() && composed {
                 let mut schema = schema.clone();
-                if let Some(obj) = schema["allOf"].as_object_mut() {
-                    obj.remove("allOf");
-                }
+                // Remove the allOf because we're resolving in this spot -- not doing so will cause
+                // infinite recursion.
+                schema
+                    .as_object_mut()
+                    .expect("schema is an object")
+                    .remove("allOf");
 
                 let mut merged_all_of = Value::Object(serde_json::Map::default());
 
@@ -720,3 +723,40 @@ mod formats {
         semver::VersionReq::parse(value).is_ok()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use crate::environment::native::NativeEnvironment;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn test_all_of_composed() {
+        let schemas = new_schemas();
+        let schema_url = url_for_test_schema("all-of-composed.json");
+
+        // Ensure this doesn't panic: this ensures that allOfs don't cause infinite recursion.
+        schemas
+            .possible_schemas_from(&schema_url, &serde_json::Value::Null, &Keys::empty(), 8)
+            .await
+            .unwrap();
+    }
+
+    fn new_schemas() -> Schemas<NativeEnvironment> {
+        Schemas::new(NativeEnvironment::new(), reqwest::Client::new())
+    }
+
+    fn url_for_test_schema(name: &str) -> Url {
+        let dir = Path::new(env!("CARGO_MANIFEST_DIR"));
+        let path = dir
+            .parent()
+            .unwrap()
+            .parent()
+            .unwrap()
+            .join("test-data/schemas")
+            .join(name);
+        Url::parse(&format!("file://{}", path.display())).unwrap()
+    }
+}

test-data/schemas/all-of-composed.json

@@ -0,0 +1,23 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "properties": {
+        "duration": {
+            "allOf": [
+                {
+                  "$ref": "#/definitions/Duration"
+                }
+            ]
+        }
+    },
+    "definitions": {
+        "Duration": {
+            "title": "Duration",
+            "description": "A duration, specified in a human-readable format.",
+            "examples": [
+                "60s",
+                "1w 3d"
+            ],
+            "type": "string"
+        }
+    }
+}