Ambiguous error message when decompressing brotli stream

[GreenYun]

I did this

1. compile curl with broti support
2. run curl command line: curl --compressed -o example https://example.com
3. got "curl: (23) Failed writing received data to disk/application" while the downloaded file is intact

I expected the following

The error message should be omitted if end of downloading stream encountered.

After digging into the code as well as the server response, I found:

1. the server did not send Content-Length and curl may not know when the stream ends (current Nginx implementation will strip Content-Length because the stream length after compressed is not predictable)
2. Botli support in curl returns CURLE_WRITE_ERROR when unexpectedly reaching end of stream, ref:

   curl/lib/content_encoding.c

   Line 676 in c8e0cd1

   return CURLE_WRITE_ERROR; /* Stream already ended. */

P.S. Zstd writer in curl will not return CURLE_WRITE_ERROR when Content-Length is not specified in response header.

curl/libcurl version

curl 8.7.1

operating system

macOS 12.7.4

[bagder]

I believe this is already fixed in master via b30d694.

[bagder]

First reported in #13209