[Docs] Update v16 migration guide

[tobias-tengler]

No description provided.

[Copilot]

Pull request overview

Updates the HotChocolate v16 migration guide to document breaking changes around OperationResult construction/mutation and a rename in runtime type abstractions.

Changes:

• Added guidance for replacing usages of OperationResultBuilder (now internal) with direct OperationResult construction and immutable updates.
• Documented OperationResult API changes (removal of IOperationResult, non-null Errors/Extensions).
• Added note about renaming IHasRuntimeType to IRuntimeTypeProvider.

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[Copilot]

The sample constructs an OperationResult with empty errors and empty extensions. In v16 OperationResult(ImmutableList<IError> errors, ...) throws when errors.Count == 0, and the other constructor also rejects having no data + no errors + no extensions. Update the snippet to show a valid construction (e.g., provide at least one error, or create the result with non-empty extensions, or include data).

[Copilot]

ImmutableOrderedDictionary.Create([]) will not compile as written because the generic type arguments cannot be inferred from an empty collection expression. Use ImmutableOrderedDictionary<string, object?>.Empty or specify the generic arguments explicitly (e.g., Create<string, object?>(...)).

Suggested change

	var extensions = ImmutableOrderedDictionary.Create([]);
	var extensions = ImmutableOrderedDictionary<string, object?>.Empty;

[Copilot]

This sentence reads self-contradictory: “immutable data structures that can be modified.” Consider clarifying that these are immutable collections updated via non-destructive operations (e.g., SetItem returns a new instance) to avoid confusion for readers.

Suggested change

	Most of the properties you'd want to modify are now immutable data structures that can be modified.
	Most of the properties you'd want to change now expose immutable collection types; use their non-destructive update methods (for example, `SetItem` returns a new instance) and assign the returned value back to the property.

[github-actions]

🚀 Fusion Gateway Performance Results

Simple Composite Query

Constant Load (50 VUs)

Requests/sec	Error Rate
2912.81 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.81ms	15.01ms	171.70ms	16.94ms	30.90ms	36.37ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
3313.93 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.67ms	66.70ms	230.14ms	67.22ms	123.25ms	138.76ms

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
745.58 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
8.82ms	62.21ms	389.74ms	65.50ms	81.41ms	90.24ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
810.01 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
1.86ms	256.20ms	708.86ms	264.67ms	526.92ms	566.42ms

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
23779.87 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.10ms	1.69ms	52.89ms	2.05ms	3.91ms	4.79ms

Ramping Load (0→50→500→50 VUs)

Requests/sec	Error Rate
18930.07 req/s	0.00%

📊 Response Time Metrics

Min	Med	Max	Avg	P90	P95
0.10ms	9.16ms	116.36ms	11.16ms	22.98ms	27.70ms

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.

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Run 22104598531 • Commit 11f7e10 • Tue, 17 Feb 2026 15:49:18 GMT