Adopt spector/parameters/path (#7237)

fixes: #7053

Author: jorgerangel-msft

packages/http-client-csharp/generator/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/RestClientProvider.cs

@@ -234,7 +234,7 @@ private IEnumerable<MethodBodyStatement> AppendHeaderParameters(HttpRequestApi r
                 if (!TryGetSpecialHeaderParam(inputParameter, out _) && (!inputParameter.IsRequired || type?.IsNullable == true ||
                    (type is { IsValueType: false, IsFrameworkType: true } && type.FrameworkType != typeof(string))))
                 {
-                    statement = BuildQueryOrHeaderParameterNullCheck(type, valueExpression, statement);
+                    statement = BuildQueryOrHeaderOrPathParameterNullCheck(type, valueExpression, statement);
                 }
 
                 statements.Add(statement);
@@ -309,7 +309,7 @@ private static List<MethodBodyStatement> AppendQueryParameters(ScopedApi uri, In
                 if (!inputParameter.IsRequired || paramType?.IsNullable == true ||
                     (paramType is { IsValueType: false, IsFrameworkType: true } && paramType.FrameworkType != typeof(string)))
                 {
-                    statement = BuildQueryOrHeaderParameterNullCheck(paramType, valueExpression, statement);
+                    statement = BuildQueryOrHeaderOrPathParameterNullCheck(paramType, valueExpression, statement);
                 }
 
                 statements.Add(statement);
@@ -318,7 +318,7 @@ private static List<MethodBodyStatement> AppendQueryParameters(ScopedApi uri, In
             return statements;
         }
 
-        private static IfStatement BuildQueryOrHeaderParameterNullCheck(
+        private static IfStatement BuildQueryOrHeaderOrPathParameterNullCheck(
             CSharpType? parameterType,
             ValueExpression valueExpression,
             MethodBodyStatement originalStatement)
@@ -384,7 +384,8 @@ private void AddUriSegments(
                     break;
                 }
 
-                statements.Add(uri.AppendPath(Literal(pathSpan.Slice(0, paramIndex).ToString()), false).Terminate());
+                var path = pathSpan.Slice(0, paramIndex);
+                statements.Add(uri.AppendPath(Literal(path.ToString()), false).Terminate());
                 pathSpan = pathSpan.Slice(paramIndex + 1);
                 var paramEndIndex = pathSpan.IndexOf('}');
                 var paramName = pathSpan.Slice(0, paramEndIndex).ToString();
@@ -424,7 +425,23 @@ private void AddUriSegments(
                     valueExpression = type?.Equals(typeof(string)) == true
                         ? valueExpression
                         : valueExpression.Invoke(nameof(ToString), toStringParams);
-                    statements.Add(uri.AppendPath(valueExpression, escape).Terminate());
+                    MethodBodyStatement statement;
+                    if (inputParam?.IsRequired == false)
+                    {
+                        bool shouldPrependWithPathSeparator = path.Length > 0 && path[^1] != '/';
+                        List<MethodBodyStatement> appendPathStatements = shouldPrependWithPathSeparator
+                            ? [uri.AppendPath(Literal("/"), false).Terminate(), uri.AppendPath(valueExpression, escape).Terminate()]
+                            : [uri.AppendPath(valueExpression, escape).Terminate()];
+                        statement = BuildQueryOrHeaderOrPathParameterNullCheck(
+                            type,
+                            valueExpression,
+                            appendPathStatements);
+                    }
+                    else
+                    {
+                        statement = uri.AppendPath(valueExpression, escape).Terminate();
+                    }
+                    statements.Add(statement);
                 }
 
                 pathSpan = pathSpan.Slice(paramEndIndex + 1);

packages/http-client-csharp/generator/TestProjects/Spector.Tests/Http/Parameters/Path/PathTests.cs

@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.ClientModel;
+using System.ClientModel.Primitives;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using Parameters.Path;
+
+namespace TestProjects.Spector.Tests.Http.Parameters.Path
+{
+    public class PathTests : SpectorTestBase
+    {
+        [SpectorTest]
+        public Task Normal() => Test(async (host) =>
+        {
+            var client = new PathClient(host, null);
+            var name = "foo";
+            ClientResult response = await client.NormalAsync(name);
+            Assert.AreEqual(204, response.GetRawResponse().Status);
+        });
+
+        [SpectorTest]
+        [TestCase(true)]
+        [TestCase(false)]
+        public Task OptionalPathParamIncluded(bool isOptional) => Test(async (host) =>
+        {
+            var client = new PathClient(host, null);
+            string? name = isOptional ? null : "foo";
+            ClientResult response = await client.OptionalAsync(name);
+            Assert.AreEqual(204, response.GetRawResponse().Status);
+        });
+    }
+}

packages/http-client-csharp/generator/TestProjects/Spector.Tests/TestProjects.Spector.Tests.csproj

@@ -40,6 +40,7 @@
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\parameters\body-optionality\src\Parameters.BodyOptionality.csproj" />
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\parameters\collection-format\src\Parameters.CollectionFormat.csproj" />
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\parameters\spread\src\Parameters.Spread.csproj" />
+    <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\parameters\path\src\Parameters.Path.csproj" />
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\payload\content-negotiation\src\Payload.ContentNegotiation.csproj" />
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\payload\json-merge-patch\src\Payload.JsonMergePatch.csproj" />
     <ProjectReference Include="$(RepoRoot)\TestProjects\Spector\http\payload\media-type\src\Payload.MediaType.csproj" />