diff --git a/.changepacks/changepack_log_FHWJJPPxJTLxVPGXE7Tf3.json b/.changepacks/changepack_log_FHWJJPPxJTLxVPGXE7Tf3.json
new file mode 100644
index 0000000..84a3c50
--- /dev/null
+++ b/.changepacks/changepack_log_FHWJJPPxJTLxVPGXE7Tf3.json
@@ -0,0 +1 @@
+{"changes":{"Cargo.toml":"Patch"},"note":"Fix schema_type has_one","date":"2026-04-01T14:13:09.811093500Z"}
\ No newline at end of file
diff --git a/crates/vespera_macro/src/schema_macro/type_utils.rs b/crates/vespera_macro/src/schema_macro/type_utils.rs
index 6658fa7..08937ab 100644
--- a/crates/vespera_macro/src/schema_macro/type_utils.rs
+++ b/crates/vespera_macro/src/schema_macro/type_utils.rs
@@ -16,15 +16,19 @@ pub const PRIMITIVE_TYPE_NAMES: &[&str] = &[
     "f64", "bool", "String", "Decimal",
 ];
 
-/// Normalize a `TokenStream` or `Type` to a compact string by removing spaces.
+/// Normalize a `TokenStream` or `Type` to a compact string by removing all whitespace.
 ///
 /// This replaces the common `.to_string().replace(' ', "")` pattern used throughout
 /// the codebase to produce deterministic path strings for comparison and cache keys.
+///
+/// Removes spaces, newlines, and carriage returns — `proc_macro2`'s `Display` impl
+/// may insert newlines when token sequences exceed an internal line-length threshold,
+/// which would break substring checks like `contains("HasOne<")`.
 #[inline]
 pub fn normalize_token_str(displayable: &impl std::fmt::Display) -> String {
     let s = displayable.to_string();
-    if s.contains(' ') {
-        s.replace(' ', "")
+    if s.contains(|c: char| c.is_ascii_whitespace()) {
+        s.replace(|c: char| c.is_ascii_whitespace(), "")
     } else {
         s
     }
diff --git a/examples/axum-example/models/single.json b/examples/axum-example/models/single.json
new file mode 100644
index 0000000..8e65f4c
--- /dev/null
+++ b/examples/axum-example/models/single.json
@@ -0,0 +1,12 @@
+{
+  "$schema": "https://raw.githubusercontent.com/dev-five-git/vespertide/refs/heads/main/schemas/model.schema.json",
+  "name": "single",
+  "columns": [
+    {
+      "name": "username",
+      "type": { "kind": "varchar", "length": 32 },
+      "nullable": false,
+      "primary_key": true
+    }
+  ]
+}
diff --git a/examples/axum-example/models/single_rel.json b/examples/axum-example/models/single_rel.json
new file mode 100644
index 0000000..7eb6773
--- /dev/null
+++ b/examples/axum-example/models/single_rel.json
@@ -0,0 +1,17 @@
+{
+  "$schema": "https://raw.githubusercontent.com/dev-five-git/vespertide/refs/heads/main/schemas/model.schema.json",
+  "name": "single_rel",
+  "columns": [
+    {
+      "name": "username",
+      "type": { "kind": "varchar", "length": 32 },
+      "nullable": false,
+      "primary_key": true,
+      "foreign_key": {
+        "ref_table": "single",
+        "ref_columns": ["username"],
+        "on_delete": "cascade"
+      }
+    }
+  ]
+}
diff --git a/examples/axum-example/openapi.json b/examples/axum-example/openapi.json
index bf41bd6..df9656c 100644
--- a/examples/axum-example/openapi.json
+++ b/examples/axum-example/openapi.json
@@ -3467,6 +3467,60 @@
           "createdAt"
         ]
       },
+      "SingleRelSchema": {
+        "type": "object",
+        "properties": {
+          "single": {
+            "$ref": "#/components/schemas/SingleRelSchema_Single"
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username",
+          "single"
+        ]
+      },
+      "SingleRelSchema_Single": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema": {
+        "type": "object",
+        "properties": {
+          "singleRel": {
+            "$ref": "#/components/schemas/SingleSchema_SingleRel",
+            "nullable": true
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema_SingleRel": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
       "SkipResponse": {
         "type": "object",
         "properties": {
diff --git a/examples/axum-example/src/models/mod.rs b/examples/axum-example/src/models/mod.rs
index 02ee003..0c26e48 100644
--- a/examples/axum-example/src/models/mod.rs
+++ b/examples/axum-example/src/models/mod.rs
@@ -1,5 +1,7 @@
 pub mod config;
 pub mod memo;
 pub mod memo_comment;
+pub mod single;
+pub mod single_rel;
 pub mod user;
 pub mod uuid_item;
diff --git a/examples/axum-example/src/models/single.rs b/examples/axum-example/src/models/single.rs
new file mode 100644
index 0000000..9e3a48a
--- /dev/null
+++ b/examples/axum-example/src/models/single.rs
@@ -0,0 +1,15 @@
+#![allow(dead_code)]
+use sea_orm::entity::prelude::*;
+
+#[sea_orm::model]
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "single")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub username: String,
+    #[sea_orm(has_one)]
+    pub single_rel: HasOne<crate::models::single_rel::Entity>,
+}
+
+vespera::schema_type!(Schema from Model, name = "SingleSchema");
+impl ActiveModelBehavior for ActiveModel {}
diff --git a/examples/axum-example/src/models/single_rel.rs b/examples/axum-example/src/models/single_rel.rs
new file mode 100644
index 0000000..14323d6
--- /dev/null
+++ b/examples/axum-example/src/models/single_rel.rs
@@ -0,0 +1,15 @@
+#![allow(dead_code)]
+use sea_orm::entity::prelude::*;
+
+#[sea_orm::model]
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel)]
+#[sea_orm(table_name = "single_rel")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub username: String,
+    #[sea_orm(belongs_to, from = "username", to = "username")]
+    pub single: HasOne<crate::models::single::Entity>,
+}
+
+vespera::schema_type!(Schema from Model, name = "SingleRelSchema");
+impl ActiveModelBehavior for ActiveModel {}
diff --git a/examples/axum-example/tests/snapshots/integration_test__openapi.snap b/examples/axum-example/tests/snapshots/integration_test__openapi.snap
index be6d493..b7d5c7b 100644
--- a/examples/axum-example/tests/snapshots/integration_test__openapi.snap
+++ b/examples/axum-example/tests/snapshots/integration_test__openapi.snap
@@ -3471,6 +3471,60 @@ expression: "std::fs::read_to_string(\"openapi.json\").unwrap()"
           "createdAt"
         ]
       },
+      "SingleRelSchema": {
+        "type": "object",
+        "properties": {
+          "single": {
+            "$ref": "#/components/schemas/SingleRelSchema_Single"
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username",
+          "single"
+        ]
+      },
+      "SingleRelSchema_Single": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema": {
+        "type": "object",
+        "properties": {
+          "singleRel": {
+            "$ref": "#/components/schemas/SingleSchema_SingleRel",
+            "nullable": true
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema_SingleRel": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
       "SkipResponse": {
         "type": "object",
         "properties": {
diff --git a/openapi.json b/openapi.json
index bf41bd6..df9656c 100644
--- a/openapi.json
+++ b/openapi.json
@@ -3467,6 +3467,60 @@
           "createdAt"
         ]
       },
+      "SingleRelSchema": {
+        "type": "object",
+        "properties": {
+          "single": {
+            "$ref": "#/components/schemas/SingleRelSchema_Single"
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username",
+          "single"
+        ]
+      },
+      "SingleRelSchema_Single": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema": {
+        "type": "object",
+        "properties": {
+          "singleRel": {
+            "$ref": "#/components/schemas/SingleSchema_SingleRel",
+            "nullable": true
+          },
+          "username": {
+            "type": "string",
+            "default": ""
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
+      "SingleSchema_SingleRel": {
+        "type": "object",
+        "properties": {
+          "username": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "username"
+        ]
+      },
       "SkipResponse": {
         "type": "object",
         "properties": {