From d5a379287247215ab432b3d351d08d52a8345bf5 Mon Sep 17 00:00:00 2001
From: 1lutz <lutzgog@gmail.com>
Date: Sat, 19 Aug 2023 08:54:54 +0000
Subject: [PATCH 1/2] add discriminator mapping

---
 utoipa/src/openapi/schema.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/utoipa/src/openapi/schema.rs b/utoipa/src/openapi/schema.rs
index 1759ccd3..fd622382 100644
--- a/utoipa/src/openapi/schema.rs
+++ b/utoipa/src/openapi/schema.rs
@@ -284,6 +284,10 @@ pub struct Discriminator {
     /// Defines a discriminator property name which must be found within all composite
     /// objects.
     pub property_name: String,
+
+    // An object to hold mappings between payload values and schema names or references.
+    #[serde(skip_serializing_if = "BTreeMap::is_empty", default)]
+    pub mapping: BTreeMap<String, String>,
 }
 
 impl Discriminator {
@@ -299,6 +303,7 @@ impl Discriminator {
     pub fn new<I: Into<String>>(property_name: I) -> Self {
         Self {
             property_name: property_name.into(),
+            mapping: BTreeMap::new(),
         }
     }
 }

From c2834c575716219ba4226fc3ac6ed0c1ae0bd01e Mon Sep 17 00:00:00 2001
From: 1lutz <lutzgog@gmail.com>
Date: Wed, 20 Sep 2023 09:32:13 +0000
Subject: [PATCH 2/2] improve comment and add test for mapping

---
 utoipa/src/openapi/schema.rs | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/utoipa/src/openapi/schema.rs b/utoipa/src/openapi/schema.rs
index 50150d9f..53d3c76a 100644
--- a/utoipa/src/openapi/schema.rs
+++ b/utoipa/src/openapi/schema.rs
@@ -285,7 +285,9 @@ pub struct Discriminator {
     /// objects.
     pub property_name: String,
 
-    // An object to hold mappings between payload values and schema names or references.
+    /// An object to hold mappings between payload values and schema names or references.
+    /// This field can only be populated manually. There is no macro support and no
+    /// validation.
     #[serde(skip_serializing_if = "BTreeMap::is_empty", default)]
     pub mapping: BTreeMap<String, String>,
 }
@@ -2042,4 +2044,34 @@ mod tests {
 
         assert_eq!(json_str, json_de_str);
     }
+
+    #[test]
+    fn serialize_discriminator_with_mapping() {
+        let mut discriminator = Discriminator::new("type");
+        discriminator.mapping = [("int".to_string(), "#/components/schemas/MyInt".to_string())]
+            .into_iter()
+            .collect::<BTreeMap<_, _>>();
+        let one_of = OneOfBuilder::new()
+            .item(Ref::from_schema_name("MyInt"))
+            .discriminator(Some(discriminator))
+            .build();
+        let json_value = serde_json::to_value(one_of).unwrap();
+
+        assert_json_eq!(
+            json_value,
+            json!({
+                "oneOf": [
+                    {
+                        "$ref": "#/components/schemas/MyInt"
+                    }
+                ],
+                "discriminator": {
+                    "propertyName": "type",
+                    "mapping": {
+                        "int": "#/components/schemas/MyInt"
+                    }
+                }
+            })
+        );
+    }
 }