[OpenAPI] Support default values

[tobias-tengler]

No description provided.

[Copilot]

Pull request overview

This PR implements support for default values in OpenAPI document generation. The changes enable GraphQL operations with default parameter values to be properly represented in the generated OpenAPI specification, allowing parameters with defaults to be optional in HTTP requests.

Key Changes:

• Added logic to detect and propagate default values from GraphQL variables and input object fields through to OpenAPI schemas
• Modified parameter handling to skip inserting values when defaults exist and no value is provided
• Extended OpenAPI schema generation to include default value representations

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
TestSchema.cs	Added test models (DeeplyNested, DeeplyNested2) with DefaultValue attribute for testing
OpenApiTestBase.cs	Added test mutation for deeply nested object with default value in query parameter
OpenApiIntegrationTestBase.cs	Added test case to verify default value handling in operation documents
HttpEndpointIntegrationTestBase.cs	Added integration tests for GET and PUT operations without query parameters that have defaults
OpenApiEndpointFactory.cs	Modified to extract and track whether parameters have default values
OpenApiEndpointDescriptor.cs	Extended VariableValueInsertionTrieLeaf to include HasDefaultValue flag
DynamicEndpointMiddleware.cs	Changed parameter insertion logic to skip values when defaults exist and no value provided
DynamicOpenApiDocumentTransformer.cs	Enhanced schema generation to include default values and reordered input/output object handling
Snapshot files (multiple)	Updated expected OpenAPI output to include default values in schemas

Comments suppressed due to low confidence (1)

src/HotChocolate/Adapters/src/Adapters.OpenApi.Core/Execution/DynamicEndpointMiddleware.cs:204

• This TODO comment should be addressed before merging. If this situation should lead to a bad request, the implementation should be completed rather than leaving it as a TODO.

                    throw new InvalidOperationException(

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[github-actions]

🚀 Fusion Gateway Performance Results

Simple Composite Query

Constant Load (50 VUs)

Requests/sec	Error Rate
5970.81 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.75ms	7.05ms	160.05ms	8.22ms	12.35ms	18.26ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
4585.98 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.79ms	38.88ms	247.49ms	48.51ms	109.60ms	125.92ms

Executed Query

fragment User on User {
  id
  username
  name
}

fragment Review on Review {
  id
  body
}

fragment Product on Product {
  inStock
  name
  price
  shippingEstimate
  upc
  weight
}

query TestQuery {
  topProducts(first: 5) {
    ...Product
    reviews {
      ...Review
      author {
        ...User
      }
    }
  }
}

Deep Recursion Query

Constant Load (50 VUs)

Requests/sec	Error Rate
269.62 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
12.73ms	175.33ms	593.87ms	179.96ms	226.16ms	251.42ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
306.48 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
3.02ms	656.51ms	1691.75ms	691.19ms	1366.93ms	1471.60ms

Executed Query

fragment User on User {
  id
  username
  name
}

fragment Review on Review {
  id
  body
}

fragment Product on Product {
  inStock
  name
  price
  shippingEstimate
  upc
  weight
}

query TestQuery {
  users {
    ...User
    reviews {
      ...Review
      product {
        ...Product
        reviews {
          ...Review
          author {
            ...User
            reviews {
              ...Review
              product {
                ...Product
              }
            }
          }
        }
      }
    }
  }
  topProducts(first: 5) {
    ...Product
    reviews {
      ...Review
      author {
        ...User
        reviews {
          ...Review
          product {
            ...Product
          }
        }
      }
    }
  }
}

Variable Batching Throughput

Constant Load (50 VUs)

Requests/sec	Error Rate
24145.42 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.09ms	1.67ms	41.52ms	2.02ms	3.85ms	4.70ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
19029.89 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.09ms	8.98ms	102.73ms	11.08ms	23.08ms	27.77ms

Executed Query

query TestQuery_8f7a46ce_2(
  $__fusion_1_upc: ID!
  $__fusion_2_price: Long!
  $__fusion_2_weight: Long!
) {
  productByUpc(upc: $__fusion_1_upc) {
    inStock
    shippingEstimate(weight: $__fusion_2_weight, price: $__fusion_2_price)
  }
}

Variables (5 sets batched in single request)

[
  { "__fusion_1_upc": "1", "__fusion_2_price": 899, "__fusion_2_weight": 100 },
  { "__fusion_1_upc": "2", "__fusion_2_price": 1299, "__fusion_2_weight": 1000 },
  { "__fusion_1_upc": "3", "__fusion_2_price": 15, "__fusion_2_weight": 20 },
  { "__fusion_1_upc": "4", "__fusion_2_price": 499, "__fusion_2_weight": 100 },
  { "__fusion_1_upc": "5", "__fusion_2_price": 1299, "__fusion_2_weight": 1000 }
]

No baseline data available for comparison.

---

Run 20061553251 • Commit 771aa37 • Tue, 09 Dec 2025 11:37:09 GMT

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (bf6547e) to head (9814c77).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #8986   +/-   ##
============================
============================

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.