build_mock_url() give different paths for the same multipart request

[jmaspons]

I found that the paths on Linux/Mac are different from the Windows one. Only for multipart requests. Could explain the failing test in #40 (but not related to the form_data VS character content), see https://github.com/nealrichardson/httptest2/actions/runs/8881677497/job/24384594955?pr=40 or https://github.com/jmaspons/osmapiR/actions/runs/9210988574/job/25339688825

No idea how to fix it, and difficult to reproduce because it depends on the OS.

[nealrichardson]

This feels familiar and I thought I had dealt with this before. My guess would be that it's a difference of path separators. Probably inserting a gsub("\\", "/", x) in there would standardize. (normalizePath() could do this but it also expands the path, and absolute paths will definitely not match across systems.)

[nealrichardson]

On #40 we saw this happening because of CRLF differences in text files. For multipart forms, if there is a curl::form_file(), we hash the file contents, not the file path, so backslashes shouldn't be relevant.

Reading the source in https://github.com/jmaspons/osmapiR (and in xml2), it wasn't obvious to me where that would be coming from. And even so, it's not obvious what to do about CRLF here, if anything.

[jmaspons]

Seems that you spot the problem and the solutions at ropensci/osmapiR#28

We can close this issue documenting the trick in the readme or vignette