ghcup is not using proxy whatsoever

• Version: v0.1.16.2
• System: macOS Catalina
• Shell: fish

I am trying to use ghcup to install stack via an HTTP proxy, however it fails to respect the http_proxy nor https_proxy variable. I looked up in lib/GHCup/Download.hs and found the undocumented environment variable GHCUP_CURL_OPTS, but setting it to -x <proxy> seems not working at all:

[ Error ] Download failed: Process "curl" with arguments ["-fL","-o","/private/var/folders/hq/2htlz6gs72j4r9wld47vx1zr0000gr/T/ghcup-c35d1f21b84b2248/stack-2.7.3-osx-x86_64.tar.gz","https://github.com/commercialhaskell/stack/releases/download/v2.7.3/stack-2.7.3-osx-x86_64.tar.gz"] failed with exit code 28.

Is there any way to use ghcup behind a proxy?

I found it was an issue with my shell, and the GHCUP_CURL_OPTS can indeed work by now. However I hope the environment variable could be documented.

closed

It is documented https://gitlab.haskell.org/haskell/ghcup-hs#env-variables