oapi-codegen · jamietanna · Feb 24, 2026 · Feb 24, 2026
@@ -0,0 +1,7 @@
+package: issue2031
+generate:
+  models: true
+  client: true
+output-options:
+  prefer-skip-optional-pointer: true
+output: issue2031.gen.go
@@ -0,0 +1,3 @@
+package issue2031
+
+//go:generate go run github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen --config=config.yaml openapi.yaml
@@ -0,0 +1,63 @@
+package issue2031
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewGetTestRequest(t *testing.T) {
+	t.Run("does not add the user_ids[] parameter if zero value", func(t *testing.T) {
+		params := GetTestParams{}
+
+		req, err := NewGetTestRequest("https://localhost", &params)
+		require.NoError(t, err)
+
+		assert.Equal(t, "https://localhost/test", req.URL.String())
+	})
+
+	t.Run("does not add the user_ids[] parameter if nil", func(t *testing.T) {
+		params := GetTestParams{
+			UserIds: nil,
+		}
+
+		req, err := NewGetTestRequest("https://localhost", &params)
+		require.NoError(t, err)
+
+		assert.Equal(t, "https://localhost/test", req.URL.String())
+	})
+
+	t.Run("adds the user_ids[] parameter if an explicitly initialised empty array", func(t *testing.T) {
+		params := GetTestParams{
+			UserIds: []int{},
+		}
+
+		req, err := NewGetTestRequest("https://localhost", &params)
+		require.NoError(t, err)
+
+		assert.Equal(t, "https://localhost/test?user_ids%5B%5D=", req.URL.String())
+	})
+
+	t.Run("adds the user_ids[] parameter if array contains a value", func(t *testing.T) {
+		params := GetTestParams{
+			UserIds: []int{1},
+		}
+
+		req, err := NewGetTestRequest("https://localhost", &params)
+		require.NoError(t, err)
+
+		assert.Equal(t, "https://localhost/test?user_ids%5B%5D=1", req.URL.String())
+	})
+
+	t.Run("handles multiple user_ids[] parameters", func(t *testing.T) {
+		params := GetTestParams{
+			UserIds: []int{1, 100},
+		}
+
+		req, err := NewGetTestRequest("https://localhost", &params)
+		require.NoError(t, err)
+
+		assert.Equal(t, "https://localhost/test?user_ids%5B%5D=1&user_ids%5B%5D=100", req.URL.String())
+	})
+}
@@ -0,0 +1,17 @@
+openapi: "3.0.0"
+info:
+  version: 1.0.0
+  title: Issue 2031
+paths:
+  /test:
+    get:
+      parameters:
+        - name: "user_ids[]"
+          in: query
+          schema:
+            type: array
+            items:
+              type: integer
+          style: form
+          explode: true
+          required: false
@@ -44,6 +44,23 @@ func (pd ParameterDefinition) TypeDef() string {
 	return typeDecl
 }
 
+// RequiresNilCheck indicates whether the generated property should have a nil check performed on it before other checks.
+// This should be used in templates when performing `nil` checks, but NOT when i.e. determining if there should be an optional pointer given to the type - in that case, use `HasOptionalPointer`
+func (pd ParameterDefinition) RequiresNilCheck() bool {
+	return pd.ZeroValueIsNil() || pd.HasOptionalPointer()
+}
+
+// ZeroValueIsNil is a helper function to determine if the given Go type used for this property
+// Will return true if the OpenAPI `type` is:
+// - `array`
+func (pd ParameterDefinition) ZeroValueIsNil() bool {
+	if pd.Schema.OAPISchema == nil {
+		return false
+	}
+
+	return pd.Schema.OAPISchema.Type.Is("array")
+}
+
 // JsonTag generates the JSON annotation to map GoType to json type name. If Parameter
 // Foo is marshaled to json as "foo", this will create the annotation
 // 'json:"foo"'

@@ -197,7 +197,7 @@ func New{{$opid}}Request{{if .HasBody}}WithBody{{end}}(server string{{genParamAr
     if params != nil {
         queryValues := queryURL.Query()
             {{range $paramIdx, $param := .QueryParams}}
-            {{if .HasOptionalPointer}} if params.{{.GoName}} != nil { {{end}}
+            {{if .RequiresNilCheck}} if params.{{.GoName}} != nil { {{end}}
             {{if .IsPassThrough}}
             queryValues.Add("{{.ParamName}}", {{if .HasOptionalPointer}}*{{end}}params.{{.GoName}})
             {{end}}
@@ -210,7 +210,7 @@ func New{{$opid}}Request{{if .HasBody}}WithBody{{end}}(server string{{genParamAr
 
             {{end}}
             {{if .IsStyled}}
-            if queryFrag, err := runtime.StyleParamWithLocation("{{.Style}}", {{.Explode}}, "{{.ParamName}}", runtime.ParamLocationQuery, {{if .HasOptionalPointer}}*{{end}}params.{{.GoName}}); err != nil {
+            if queryFrag, err := runtime.StyleParamWithLocation("{{.Style}}", {{.Explode}}, "{{.ParamName}}", runtime.ParamLocationQuery, {{if and .RequiresNilCheck .HasOptionalPointer}}*{{end}}params.{{.GoName}}); err != nil {
                 return nil, err
             } else if parsed, err := url.ParseQuery(queryFrag); err != nil {
                return nil, err
@@ -222,7 +222,7 @@ func New{{$opid}}Request{{if .HasBody}}WithBody{{end}}(server string{{genParamAr
                }
             }
             {{end}}
-            {{if .HasOptionalPointer}}}{{end}}
+            {{if .RequiresNilCheck}}}{{end}}
         {{end}}
         queryURL.RawQuery = queryValues.Encode()
     }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		package issue2031

		//go:generate go run github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen --config=config.yaml openapi.yaml