fix: bug found with new CTS

serde_json_path/src/parser/selector/function/registry.rs

@@ -9,6 +9,13 @@ use serde_json_path_core::spec::functions::{Function, LogicalType, NodesType, Va
 ///
 /// These come directly from the JSONPath specification, which includes a registry of standardized
 /// functions.
+///
+/// # Note
+///
+/// There is a function in `serde_json_path_core/src/spec/functions.rs` that gives
+/// the return type for each function registered here. When adding new functions to
+/// the register, i.e., when new functions are standardized, the function there needs
+/// to be updated too.
 pub(crate) static REGISTRY: Lazy<HashMap<&'static str, &'static Function>> = Lazy::new(|| {
  let mut m = HashMap::new();
  m.insert("length", &LENGTH_FUNC);

serde_json_path_core/src/spec/functions.rs

@@ -618,14 +618,36 @@ impl FunctionExprArg {
  return Ok(f.result_type);
  }
  }
- Err(FunctionValidationError::Undefined {
- name: func.name.to_owned(),
+ registered_function_result_type(&func.name).ok_or_else(|| {
+ FunctionValidationError::Undefined {
+ name: func.name.to_owned(),
+ }
  })
  }
  }
  }
 }
 
+/// Get the result type of a registered function
+///
+/// This is a hack, but must be done, because the REGISTRY defined in `serde_json_path`
+/// is not accessible here. Therefore, this must also be maintained when new functions
+/// are added to the registry in the standard.
+///
+/// An alternative would be to define the registry of functions in core, we would then
+/// just not have the convenience macro for defining them, along with their validators
+/// and evaluators.
+fn registered_function_result_type(name: &str) -> Option<FunctionArgType> {
+ match name {
+ "length" => Some(FunctionArgType::Value),
+ "count" => Some(FunctionArgType::Value),
+ "match" => Some(FunctionArgType::Logical),
+ "search" => Some(FunctionArgType::Logical),
+ "value" => Some(FunctionArgType::Value),
+ _ => None,
+ }
+}
+
 /// Function argument types
 ///
 /// This is used to describe the type of a function argument to determine if it will be valid as a