SonarSource/sonarqube · error · IllegalArgumentException

Response from Azure for request [%s] could not be parsed: [%

Error message

Response from Azure for request [%s] could not be parsed: [%s]

What it means

doCall(request, handler) applies the response-parsing handler and catches JsonSyntaxException, rethrowing IllegalArgumentException with 'Response from Azure for request [%s] could not be parsed'. It means Azure answered with HTTP success but the body was not the expected JSON (Gson failed to deserialize it).

Source

Thrown at server/sonar-alm-client/src/main/java/org/sonar/alm/client/azure/AzureDevOpsHttpClient.java:215

      checkResponseIsSuccessful(response);
    } catch (IOException e) {
      throw new IllegalArgumentException(
        String.format(UNABLE_TO_CONTACT_AZURE_SERVER_MESSAGE_FORMAT, UNABLE_TO_CONTACT_AZURE_SERVER, request.url(), e.getMessage()),
        e);
    }
  }

  protected <G> G doGet(String token, HttpUrl url, Function<Response, G> handler) {
    Request request = prepareRequestWithToken(token, GET, url, null);
    return doCall(request, handler);
  }

  protected <G> G doCall(Request request, Function<Response, G> handler) {
    try (Response response = client.newCall(request).execute()) {
      checkResponseIsSuccessful(response);
      return handler.apply(response);
    } catch (JsonSyntaxException e) {
      throw new IllegalArgumentException(
        String.format("Response from Azure for request [%s] could not be parsed: [%s]", request.url(), e.getMessage()),
        e);
    } catch (IOException e) {
      throw new IllegalArgumentException(
        String.format(UNABLE_TO_CONTACT_AZURE_SERVER_MESSAGE_FORMAT, UNABLE_TO_CONTACT_AZURE_SERVER, request.url(), e.getMessage()),
        e);
    }
  }

  protected static Request prepareRequestWithToken(String token, String method, HttpUrl url, @Nullable RequestBody body) {
    return new Request.Builder()
      .method(method, body)
      .url(url)
      .addHeader("Authorization", encodeToken("accessToken:" + token))
      .build();
  }

  protected static void checkResponseIsSuccessful(Response response) throws IOException {

View on GitHub (pinned to 184c821202)

Solutions

  1. Log/inspect the raw response body for the failing request URL to see what was actually returned.
  2. Bypass or correctly authenticate the proxy/SSO that returns an HTML page instead of JSON.
  3. Verify the Azure DevOps Server version is supported by your SonarQube version; upgrade one side if schemas differ.
  4. Check for intermediate devices (proxies, WAFs) truncating or rewriting the response.

Example fix

// before: response is HTML from SSO login page
// after: configure SSO bypass/allowlist for /_apis on the proxy so JSON reaches SonarQube
Defensive patterns

Strategy: try-catch

Validate before calling

static boolean looksLikeJson(Response resp) throws IOException {
  String contentType = resp.header("Content-Type", "");
  return contentType.contains("application/json");
}

Type guard

static boolean isJsonContentType(String contentType) {
  return contentType != null && contentType.toLowerCase().contains("json");
}

Try / catch

try {
  List<Repo> repos = client.getRepositories(pat, org);
} catch (IllegalArgumentException e) {
  if (e.getMessage() != null && e.getMessage().contains("could not be parsed")) {
    LOG.error("Azure returned a non-JSON body (proxy/SSO page?): {}", e.getCause().getMessage());
  }
}

Prevention

When it happens

Trigger: handler.apply(response) throws JsonSyntaxException during doGet: response body is HTML (login/proxy page), empty, truncated, or JSON whose shape does not match the expected DTO.

Common situations: Reverse proxy or SSO intercepting the API call and returning an HTML login page with 200; Azure DevOps Server version returning a different JSON schema; proxy mangling the body; response truncated by a network device.

Understand the failure class

Background: "failed to unmarshal" / json.Unmarshal errors: why parsing a response into a Go struct fails and how to fix it — this error's family across 23 libraries.

Related errors

AI-assisted analysis of SonarSource/sonarqube@184c821202 (2026-09-09). Data as JSON: /api/errors/2936145751bed1f0. Report an issue: GitHub.