Merge pull request #544 from simon-pearson/feature/explode-default-value

Query Parameters Serialization - Explode doesn't respect the default value

Author: darrelmiller

src/Microsoft.OpenApi/Models/OpenApiParameter.cs

@@ -14,6 +14,8 @@ namespace Microsoft.OpenApi.Models
     /// </summary>
     public class OpenApiParameter : IOpenApiSerializable, IOpenApiReferenceable, IOpenApiExtensible
     {
+        private bool? _explode;
+
         /// <summary>
         /// Indicates if object is populated with data or is just a reference to the data
         /// </summary>
@@ -79,7 +81,11 @@ public class OpenApiParameter : IOpenApiSerializable, IOpenApiReferenceable, IOp
         /// When style is form, the default value is true.
         /// For all other styles, the default value is false.
         /// </summary>
-        public bool Explode { get; set; }
+        public bool Explode
+        {
+            get => _explode ?? Style == ParameterStyle.Form;
+            set => _explode = value;
+        }
 
         /// <summary>
         /// Determines whether the parameter value SHOULD allow reserved characters,

test/Microsoft.OpenApi.Tests/Models/OpenApiParameterTests.cs

@@ -163,6 +163,24 @@ public OpenApiParameterTests(ITestOutputHelper output)
             _output = output;
         }
 
+        [Theory]
+        [InlineData(ParameterStyle.Form, true)]
+        [InlineData(ParameterStyle.SpaceDelimited, false)]
+        [InlineData(null, false)]
+        public void WhenStyleIsFormTheDefaultValueOfExplodeShouldBeTrueOtherwiseFalse(ParameterStyle? style, bool expectedExplode)
+        {
+            // Arrange
+            var parameter = new OpenApiParameter
+            {
+                Name = "name1",
+                In = ParameterLocation.Query,
+                Style = style
+            };
+
+            // Act & Assert
+            parameter.Explode.Should().Be(expectedExplode);
+        }
+
         [Fact]
         public void SerializeBasicParameterAsV3JsonWorks()
         {