From 0ec3f026945238adad3b4f30a84e8fd71ef8935f Mon Sep 17 00:00:00 2001
From: James Tomlinson <tomo.bbe@gmail.com>
Date: Thu, 15 Aug 2024 16:26:34 +0100
Subject: [PATCH] feat: Include the parameters names CircularParameterReference
 error.

---
 pywr-schema/src/error.rs | 7 ++++---
 pywr-schema/src/model.rs | 3 ++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/pywr-schema/src/error.rs b/pywr-schema/src/error.rs
index 530796ef..586b7bf9 100644
--- a/pywr-schema/src/error.rs
+++ b/pywr-schema/src/error.rs
@@ -30,8 +30,8 @@ pub enum SchemaError {
     DataTable(#[from] TableError),
     #[error("Circular node reference(s) found.")]
     CircularNodeReference,
-    #[error("Circular parameters reference(s) found.")]
-    CircularParameterReference,
+    #[error("Circular parameters reference(s) found. Unable to load the following parameters: {0:?}")]
+    CircularParameterReference(Vec<String>),
     #[error("unsupported file format")]
     UnsupportedFileFormat,
     #[error("Python error: {0}")]
@@ -56,7 +56,8 @@ pub enum SchemaError {
     LoadParameter { name: String, error: String },
     #[error("Timeseries error: {0}")]
     Timeseries(#[from] TimeseriesError),
-    #[error("The output of literal constant values is not supported. This is because they do not have a unique identifier such as a name. If you would like to output a constant value please use a `Constant` parameter.")]
+    #[error("The output of literal constant values is not supported. This is because they do not have a unique identifier such as a name. If you would like to output a constant value please use a `Constant` parameter."
+    )]
     LiteralConstantOutputNotSupported,
     #[error("Chrono out of range error: {0}")]
     OutOfRange(#[from] chrono::OutOfRange),
diff --git a/pywr-schema/src/model.rs b/pywr-schema/src/model.rs
index 39f0a60e..a278c1a0 100644
--- a/pywr-schema/src/model.rs
+++ b/pywr-schema/src/model.rs
@@ -491,7 +491,8 @@ impl PywrNetwork {
 
                 if failed_parameters.len() == n {
                     // Could not load any parameters; must be a circular reference
-                    return Err(SchemaError::CircularParameterReference);
+                    let failed_names = failed_parameters.iter().map(|p| p.name().to_string()).collect();
+                    return Err(SchemaError::CircularParameterReference(failed_names));
                 }
 
                 remaining_parameters = failed_parameters;