Fix #8325 preserve unset Strawberry Shake input field state

[michaelstaib]

Fixes #8325

Summary

• Adds a regression test that reproduces Strawberry Shake-style runtime setters (_set_* flags) being toggled for unspecified input object fields.
• Distinguishes missing fields from explicit null during input parsing.
• Skips property setter invocation for missing non-optional input fields while preserving explicit null behavior.

Repro Test Code

[Fact]
public async Task InputParser_Does_Not_Set_Unspecified_Properties()
{
    var executor = await new ServiceCollection()
        .AddGraphQL()
        .AddQueryType<Issue8325Query>()
        .AddType<Issue8325SortInputType>()
        .BuildRequestExecutorAsync();

    var result = await executor.ExecuteAsync(
        """
        {
          isOnlyIdSet(order: [{ id: ASC }])
        }
        """);

    var json = result.ToJson();
    Assert.DoesNotContain("\"errors\"", json);
    Assert.Contains("\"isOnlyIdSet\": true", json);
}

Tests

• dotnet test src/HotChocolate/Core/test/Types.Tests/HotChocolate.Types.Tests.csproj -f net8.0 --filter "FullyQualifiedName~Issue8325ProbeTests" (Passed)
• dotnet test src/HotChocolate/Core/test/Types.Tests/HotChocolate.Types.Tests.csproj -f net9.0 --filter "FullyQualifiedName~Issue8325ProbeTests" (Passed)
• dotnet test src/HotChocolate/Core/test/Types.Tests/HotChocolate.Types.Tests.csproj -f net10.0 --filter "FullyQualifiedName~Issue8325ProbeTests" (Passed)
• dotnet test src/HotChocolate/Core/test/Types.Tests/HotChocolate.Types.Tests.csproj -f net8.0 --filter "FullyQualifiedName~InputCoercionTests" (Passed)

[github-actions]

Fusion Gateway Performance Results

Progress: 0/6 benchmarks completed — this report updates as each job finishes.

Simple Composite Query

	Req/s	Err%
Constant 2 (50 VUs)	pending	pending
Ramping 2 (0-500-0 VUs)	pending	pending

Response Times

	Min	Med	Avg	P90	P95	Max
Constant 2	pending	pending	pending	pending	pending	pending
Ramping 2	pending	pending	pending	pending	pending	pending

---

Deep Recursion Query

	Req/s	Err%
Constant 2 (50 VUs)	pending	pending
Ramping 2 (0-500-0 VUs)	pending	pending

Response Times

	Min	Med	Avg	P90	P95	Max
Constant 2	pending	pending	pending	pending	pending	pending
Ramping 2	pending	pending	pending	pending	pending	pending

---

Variable Batching Throughput

	Req/s	Err%
Constant 2 (50 VUs)	pending	pending
Ramping 2 (0-500-0 VUs)	pending	pending

Response Times

	Min	Med	Avg	P90	P95	Max
Constant 2	pending	pending	pending	pending	pending	pending
Ramping 2	pending	pending	pending	pending	pending	pending

---

Runner 2 = benchmarking-2

Run 22506557160 • Commit 93a6a30 • Fri, 27 Feb 2026 22:38:09 GMT