I am using Retrofit, OkHttp, Kotlin coroutines to make HTTP requests.

When the server returns an unsuccessful result (e.g., 404), I throw a custom exception, which is a subtype of IOException.
The resulted stack trace does not point to code that initially made a request.
The resulted stack trace only points to interceptor code, which doesn’t help me identify the original call site.

Question:

How can I ensure that when I throw a custom exception (a subtype of IOException), the stack trace points to code that initially made a request (e.g. catApi.callThatReturns404())?

Constraints:

• Wrapping every remote API call with try/catch is not an option because the issue is global, and I don’t want to wrap it in hundreds of places.
• Simply logging inside the interceptor is not sufficient since I need the full stack trace.
• Avoiding the use of the custom exception is not an option, as it holds information.
• Solution should also work in production code. Not only when some debug tools are turned on

Example code

fun main(): Unit = runBlocking {
    val api = createCatApi()
    api.callThatReturns404()
}

private fun createCatApi(): CatApi {
    val url = "https://cat-fact.herokuapp.com/"
    val httpClient = OkHttpClient.Builder()
        .addInterceptor { chain ->
            val response = chain.proceed(chain.request())
            if (!response.isSuccessful) {
                throw SubTypeOfIOException(response)
            }
            response
        }
        .build()
    val retrofit = Retrofit.Builder()
        .baseUrl(url)
        .addConverterFactory(JacksonConverterFactory.create(ObjectMapper().registerKotlinModule()))
        .client(httpClient)
        .build()
    return retrofit.create<CatApi>()
}

interface CatApi {
    @GET("factss")
    suspend fun callThatReturns404(): Collection<Any>
}

Stack trace, when SubTypeOfIOException is thrown

Exception in thread "main" com.SubTypeOfIOException: 404
    at com.MainKt$createCatApi$$inlined$-addInterceptor$1.intercept(OkHttpClient.kt:1082)

What I want

Exception in thread "main" com.retrofit_test.SubTypeOfIOException: 404
    at com.retrofit_test.Main.main(Main.kt:15)
Caused by: com.SubTypeOfIOException: 404
    at com.MainKt$createCatApi$$inlined$-addInterceptor$1.intercept(OkHttpClient.kt:1082)

Interesting thing: when I call such code from tests and throw IOException, the stack trace contains information I want. If in tests I throw a subtype of IOException, the stack trace does not contain such information

Versions:

• org.jetbrains.kotlinx:kotlinx-coroutines-core:1.9.0
• com.squareup.retrofit2:retrofit:2.11.0
• com.squareup.okhttp3:okhttp:4.12.0