[mszopa-foss]

throwOnAnyError (#23663) sets RestSharp's ThrowOnAnyError, which also throws HttpRequestException for every 4xx/5xx before ExceptionFactory runs, breaking the ApiException contract; transport failures surface as raw HttpRequestException.

Option stays opt-in but is implemented in ApiClient: if RestSharp recorded an ErrorException and status < 400, throw ApiException with the status (0 transport, real 2xx for deserialization failures), body and headers; 4xx/5xx still go through ExceptionFactory; retry-policy failures return the error response so the same guard covers them.

Also adds ApiException(int, string, object, Multimap<string, string>, Exception innerException) so the original RestSharp exception is kept as InnerException (stack trace preserved; the retry-policy path previously had no message at all). The constructor lives in the shared ApiException.mustache, so httpclient and unityWebRequest clients gain it too — additive, existing constructors unchanged.

Behaviour change for users who already opted into throwOnAnyError: RestSharp HttpRequestException becomes ApiException and 4xx/5xx go through ExceptionFactory.

Verified against the regenerated net4.7/MultipleFrameworks sample (refused → ApiException(0), 500 → ApiException(500) with body/headers, malformed 200 → ApiException(200)); on master the first two were HttpRequestException. Related: #15471, #8732, #10903, #15379, #15241.

cc @mandrean @shibayan @Blackclaws @lucamazzanti

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Summary by cubic

Fixes throwOnAnyError so transport and deserialization failures surface as ApiException instead of raw RestSharp HttpRequestException.

Previously the option enabled RestSharp's ThrowOnAnyError, which threw HttpRequestException for every non-2xx response before ExceptionFactory could run. Now 4xx/5xx responses keep flowing through ExceptionFactory, and only errors with status below 400 throw ApiException with the status (0 for transport failures, the real 2xx for deserialization failures), response body, and headers. The retry-policy path returns the error response so the same guard covers it.

• ApiException now accepts an inner exception so the original stack trace and message survive the wrap. The constructor lives in the shared ApiException.mustache, so the httpclient and unityWebRequest clients gain it too, additively.
• Adds tests to the MultipleFrameworks sample covering transport failure and an unparseable 2xx body, both asserting ApiException with the right status, body, and inner exception.
• Behavior change: users who already opted in now get ApiException for transport and deserialization failures, while ordinary HTTP error responses are handled by ExceptionFactory as usual.

^{Written for commit bbb5cbf. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 5 files

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Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache">

<violation number="1" location="modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache:502">
P2: For retry-policy failures, this throws an ApiException with a blank message and drops the original exception. `DeserializeRestResponseFromPolicyAsync` (the else branch this PR changed) builds `new RestResponse<T>(request) { ErrorException = policyResult.FinalException }` and never sets `ErrorMessage` or `Content`, so `response.ErrorMessage` is null and the formatted message becomes "Error calling <resource>: ". Previously `throwOnAnyError` rethrew `policyResult.FinalException` directly, keeping the message and stack/InnerException detail; the ApiException constructor has no inner-exception parameter, so that detail is now lost entirely, making retry-exhaustion failures (e.g., a socket failure) effectively undiagnosable. Use the exception's own message (falling back to `ErrorMessage`) so the message is populated for this path. The same blank-message risk applies to plain transport failures if RestSharp does not populate `ErrorMessage` alongside `ErrorException`.</violation>
</file>

[wing328]

Thanks for the PR

Are you using this fix in your production environment and confirm it works as expected ?

[mszopa-foss]

@wing328

Thanks for the PR

You're welcome, happy to :)

Are you using this fix in your production environment and confirm it works as expected ?

Not in production yet. We hit this in our own generator fork and decided it was worth upstreaming. I did add tests to the net4.7/MultipleFrameworks sample (bbb5cbf) that reproduce both cases: a minimal HttpListener stub returning an unparseable 200 body, and a connection to a port where nothing listens. Both fail against the previous ThrowOnAnyError wiring and pass with this PR.

[wing328]

👌

Let's give it a try. Thanks for the contribution.