[R] fix error handling in the R client

[mattpollock]

@Ramanth, @saigiridhar21, @wing328

This PR ensures that a client API provides the status code when generating a new ApiResponse for errors. Previously this was not done, with the result that a confusing R error was thrown while trying to handle the REST error. This obfuscated the REST errors, making them difficult to diagnose.

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---

Summary by cubic

Fixes R client error handling by always including the HTTP status code in ApiResponse and improving server error messages. This prevents secondary R errors and makes REST failures easier to debug.

• Bug Fixes
  • Populate ApiResponse with content, response, and status_code for 3xx/4xx/5xx and file-download paths.
  • Use response_as_text() and default to "API server error" only when the error body is empty.
  • Updated R generator template and regenerated sample clients.

^{Written for commit 0de41cf. Summary will update on new commits.}

[mattpollock]

local_var_resp$response can be a raw vector, meaning that the length(local_var_resp$response) is often greater than 1. This causes R errors because then local_var_resp$response == "" evaluates to a logical vector, but an if condition needs a logical scalar.

[mattpollock]

based on AI feedback I updated this to || all(local_var_resp$response == "")

[cubic-dev-ai]

4 issues found across 10 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="samples/client/echo_api/r/R/header_api.R">

<violation number="1" location="samples/client/echo_api/r/R/header_api.R:180">
P2: 5xx error handling can throw if response_as_text() returns NA (non-text body), because `local_var_error_msg == ""` yields NA and makes the `if` condition invalid.</violation>
</file>

<file name="samples/client/echo_api/r/R/body_api.R">

<violation number="1" location="samples/client/echo_api/r/R/body_api.R:261">
P2: 5xx error handling can throw when response_as_text returns NA; `local_var_error_msg == ""` yields NA and the `if` crashes for binary/invalid response bodies.</violation>
</file>

<file name="samples/client/echo_api/r/R/form_api.R">

<violation number="1" location="samples/client/echo_api/r/R/form_api.R:192">
P2: 5xx error handling can crash when response_as_text() yields character(0) or NA (empty/invalid body), because `local_var_error_msg == ""` makes the `if` condition throw instead of returning a fallback error response.</violation>
</file>

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

<violation number="1" location="modules/openapi-generator/src/main/resources/r/api.mustache:563">
P1: Primitive success path constructs ApiResponse with undefined variables (`content`, `resp`), causing runtime error and discarding the wrapper.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[wing328]

r integration tests passed via #22722

[mattpollock]

thanks!