Changelog

2.66.8

(fix): Fixed a compile error (CS9035) for discriminated unions that have required base properties. The internal constructor used for property-name deserialization is now annotated with [SetsRequiredMembers], so callers are no longer forced to set the required base properties at that call site.

2.66.6

(fix): MockServerTestGenerator now normalizes nullable date-time query and header parameters to millisecond precision, matching the fix previously applied to MockEndpointGenerator. Without this, mock-server tests for nullable date-time fields emitted matchers like "2024-01-15T09:30:00Z" while the SDK actually sent "2024-01-15T09:30:00.000Z".

2.66.5

(fix): Mock-server tests now serialize nullable date-time query and header parameters with millisecond precision so they match what the runtime sends. Previously, when a date-time field was wrapped in a nullable container (e.g. with respect-nullable-schemas: true and coerce-optional-schemas-to-nullable: false), the generated WithParam("since", "2024-01-15T09:30:00Z") omitted milliseconds while the SDK actually sent 2024-01-15T09:30:00.000Z, causing WireMock to return 404.

2.66.4

(fix): Dynamic snippets now render path-parameter arguments in IR (URL / SDK signature) order rather than in the order they happen to appear in the input request, so generated examples line up with the actual SDK method signature even when the spec lists path parameters in a different order.

2.66.2

(chore): Patch C# SDK generator container CVEs flagged in the AWS ECR / grype scan. Switch the apk upgrade to pick up the latest Alpine 3.23 patches (nghttp2, openssl, libcrypto, libssl, sqlite-libs, expat, etc.), pin a non-vulnerable set of System.* NuGet dependencies, drop the bundled PowerShell warmup so its vendored System.Net.Http 4.3.0 / System.Security.Cryptography.Xml DLLs are no longer included in the published image, and clear the System.Net.Http 4.3.0 artifact the /dependencies.csproj warmup leaves in the NuGet cache after restore.

2.66.1

(chore): Bump the C# SDK and C# model generator containers’ Node base image from node:22.22-alpine3.23 to node:24.15-alpine3.23. Aligns the generators with the rest of the Fern generator containers on a single Node major version (Node 24) and picks up Node 24’s CVE patches. The bundled npm 11.12.1 in node:24.15 already ships patched brace-expansion@5.0.4, so the C# SDK’s brace-expansion 2.0.3 replacement step is removed. The ip-address and picomatch patches are retained because the bundled versions in node:24.15 (10.1.0 and 4.0.3 respectively) are still vulnerable.

2.66.0

(feat): Add a default-timeout-in-seconds config option to the C# SDK generator. When set, the generated ClientOptions.Timeout defaults to the configured value (or Timeout.InfiniteTimeSpan when set to "infinity") instead of the previously hardcoded 30 seconds. SDK users can still override the timeout per-request via RequestOptions.Timeout.

(feat): Add an opt-in user-agent-name-from-package custom config option. When set to true, the generated client falls back to a <NuGetPackageId>/<version> User-Agent header when no platformHeaders.userAgent is set in the IR (e.g. for SDKs imported from OpenAPI), matching the TypeScript generator’s npm-package-name fallback. Defaults to false, preserving the existing behavior of emitting no User-Agent header in that case.

2.65.2

(chore): Bump generator container Node.js base image to node:22.22-alpine3.23 and apply latest Alpine package security updates at build time.

2.65.1

(chore): Patch the C# SDK generator container to remediate the 40 vulnerabilities reported by the 2026-05-06 grype scan. Bump the Node.js base image to 22.22.2-alpine3.22 (fixes Node binary CVEs and upgrades npm-bundled cross-spawn, minimatch, glob, tar, and diff), remove the unused PowerShell install bundled with dotnet/sdk:10.0-alpine to drop the vulnerable System.Security.Cryptography.Xml 10.0.5 DLL flagged by GHSA-37gx-xxp4-5rgx and GHSA-w3x6-4m5h-cxqf, run apk upgrade to pick up the nghttp2-libs CVE-2026-27135 fix, and patch npm’s bundled ip-address (10.1.1), picomatch (4.0.4), and brace-expansion (2.0.3).