From 254d19aa6d6ca9508995a7c1f95c27eedb3ef235 Mon Sep 17 00:00:00 2001
From: Jordan Wu <101218661+jordan-definitive@users.noreply.github.com>
Date: Mon, 15 Apr 2024 15:44:13 -0700
Subject: [PATCH] openapi3: keep oneOf context in markSchemaErrorKey (#940)

---
 openapi3/schema.go               |  3 +-
 openapi3/schema_issue940_test.go | 67 ++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 1 deletion(-)
 create mode 100644 openapi3/schema_issue940_test.go

diff --git a/openapi3/schema.go b/openapi3/schema.go
index ae28afef7..eafb82740 100644
--- a/openapi3/schema.go
+++ b/openapi3/schema.go
@@ -2122,7 +2122,8 @@ func markSchemaErrorKey(err error, key string) error {
 	var me multiErrorForOneOf
 
 	if errors.As(err, &me) {
-		err = me.Unwrap()
+		origin := me.Unwrap()
+		_ = markSchemaErrorKey(origin, key)
 	}
 
 	if v, ok := err.(*SchemaError); ok {
diff --git a/openapi3/schema_issue940_test.go b/openapi3/schema_issue940_test.go
new file mode 100644
index 000000000..ffcba7be1
--- /dev/null
+++ b/openapi3/schema_issue940_test.go
@@ -0,0 +1,67 @@
+package openapi3
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestOneOfErrorPreserved(t *testing.T) {
+
+	SchemaErrorDetailsDisabled = true
+	defer func() { SchemaErrorDetailsDisabled = false }()
+
+	// language=json
+	raw := `
+{
+	"foo": [ "bar" ]
+}
+`
+
+	// language=json
+	schema := `
+{
+	"type": "object",
+	"properties": {
+		"foo": {
+			"oneOf": [
+				{
+					"type": "number"
+				},
+					{
+					"type": "string"
+				}
+			]
+		}
+	}
+}
+`
+
+	s := NewSchema()
+	err := s.UnmarshalJSON([]byte(schema))
+	require.NoError(t, err)
+	err = s.Validate(context.Background())
+	require.NoError(t, err)
+
+	obj := make(map[string]interface{})
+	err = json.Unmarshal([]byte(raw), &obj)
+	require.NoError(t, err)
+
+	err = s.VisitJSON(obj, MultiErrors())
+	require.Error(t, err)
+
+	var multiError MultiError
+	ok := errors.As(err, &multiError)
+	require.True(t, ok)
+	var schemaErr *SchemaError
+	ok = errors.As(multiError[0], &schemaErr)
+	require.True(t, ok)
+
+	require.Equal(t, "oneOf", schemaErr.SchemaField)
+	require.Equal(t, "value doesn't match any schema from \"oneOf\"", schemaErr.Reason)
+	require.Equal(t, "Error at \"/foo\": doesn't match schema due to: value must be a number Or value must be a string", schemaErr.Error())
+
+}