From e03b5a87ebc61c77dc93788e369deb771e052793 Mon Sep 17 00:00:00 2001
From: Pierre Fenoll <pierrefenoll@gmail.com>
Date: Wed, 21 Sep 2022 15:52:14 +0200
Subject: [PATCH] Validate default values against schema (#610)

---
 openapi3/issue136_test.go | 53 +++++++++++++++++++++++++++++++++++++++
 openapi3/schema.go        |  6 +++++
 2 files changed, 59 insertions(+)
 create mode 100644 openapi3/issue136_test.go

diff --git a/openapi3/issue136_test.go b/openapi3/issue136_test.go
new file mode 100644
index 000000000..36c8b8588
--- /dev/null
+++ b/openapi3/issue136_test.go
@@ -0,0 +1,53 @@
+package openapi3
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestIssue136(t *testing.T) {
+	specf := func(dflt string) string {
+		return `
+openapi: 3.0.2
+info:
+  title: "Hello World REST APIs"
+  version: "1.0"
+paths: {}
+components:
+  schemas:
+    SomeSchema:
+      type: string
+      default: ` + dflt + `
+`
+	}
+
+	for _, testcase := range []struct {
+		dflt, err string
+	}{
+		{
+			dflt: `"foo"`,
+			err:  "",
+		},
+		{
+			dflt: `1`,
+			err:  "invalid components: invalid schema default: Field must be set to string or not be present",
+		},
+	} {
+		t.Run(testcase.dflt, func(t *testing.T) {
+			spec := specf(testcase.dflt)
+
+			sl := NewLoader()
+
+			doc, err := sl.LoadFromData([]byte(spec))
+			require.NoError(t, err)
+
+			err = doc.Validate(sl.Context)
+			if testcase.err == "" {
+				require.NoError(t, err)
+			} else {
+				require.Error(t, err, testcase.err)
+			}
+		})
+	}
+}
diff --git a/openapi3/schema.go b/openapi3/schema.go
index ded97f02a..9b36e604a 100644
--- a/openapi3/schema.go
+++ b/openapi3/schema.go
@@ -753,6 +753,12 @@ func (schema *Schema) validate(ctx context.Context, stack []*Schema) (err error)
 		}
 	}
 
+	if v := schema.Default; v != nil {
+		if err := schema.VisitJSON(v); err != nil {
+			return fmt.Errorf("invalid schema default: %w", err)
+		}
+	}
+
 	if x := schema.Example; x != nil && !validationOpts.ExamplesValidationDisabled {
 		if err := validateExampleValue(x, schema); err != nil {
 			return fmt.Errorf("invalid schema example: %w", err)