[SOLVED] Spring REST Docs: how to documentation multipart form list parameter?

Spring REST Docs: how to documentation multipart form list parameter?

How to documentation form list parameter?

Controller

@PostMapping("/sample")
public void post(@ModelAttribute PostRequest request) {
    // ...
}

@Data
public static class PostRequest {
    private MultipartFile file;
    private List<PostRow> rows;
}

@Data
public static class PostRow {
    private Long id;
}

My test code

mockMvc.perform(
        multipart("/sample")
                .file(new MockMultipartFile("file", "level.zip", "application/zip", "level.zip".getBytes()))
                .param("rows[0].id", "1")
                .param("rows[1].id", "2")
                .contentType(MediaType.MULTIPART_FORM_DATA)
        )
        .andDo(document(
                "Sample",
                requestParts(
                        partWithName("file").description("level zip file")
                ),
                requestParameters(
                        parameterWithName("rows[].id").description("row id")
                )
            )
        );

I tried this code, but it throws following error

Request parameters with the following names were not documented: [rows[1].id, rows[0].id]. Request parameters with the following names were not found in the request: [rows[].id]
org.springframework.restdocs.snippet.SnippetException: Request parameters with the following names were not documented: [rows[1].id, rows[0].id]. Request parameters with the following names were not found in the request: [rows[].id]
    at org.springframework.restdocs.request.RequestParametersSnippet.verificationFailed(RequestParametersSnippet.java:107)
    at org.springframework.restdocs.request.AbstractParametersSnippet.verifyParameterDescriptors(AbstractParametersSnippet.java:108)
    at org.springframework.restdocs.request.AbstractParametersSnippet.createModel(AbstractParametersSnippet.java:74)
    at org.springframework.restdocs.snippet.TemplatedSnippet.document(TemplatedSnippet.java:78)
    at org.springframework.restdocs.generate.RestDocumentationGenerator.handle(RestDocumentationGenerator.java:191)
    at org.springframework.restdocs.mockmvc.RestDocumentationResultHandler.handle(RestDocumentationResultHandler.java:52)
    at org.springframework.test.web.servlet.MockMvc$1.andDo(MockMvc.java:201)

I don't want to use "rows[0].id" and "rows[1].id".
What can I do instead?

Solution

There's nothing that you can do with REST Docs' current built-in capabilities. REST Docs has no understanding of parameter names and knows nothing of your naming scheme. That means that it can't tell that parameters that look like rows[n].id are all the same kind of parameter and should only be documented once.