dotnet-install.sh fails when dot-sourced from the command line

[JayBazuzi]

• This issue is blocking
• This issue is causing unreasonable pain

On a Mac running ZSH:

> . dotnet-install.sh   
(eval):1: FUNCNAME[0]: parameter not set
(eval):1: FUNCNAME[0]: parameter not set

and then my shell closes, ouch!

[MichalPavlik]

I can repro using zsh 5.8 (x86_64-ubuntu-linux-gnu)

[MichalPavlik]

I think I know the reason. The script instructs shell to exit if an unset variable is encountered (via set -u). The FUNCNAME[0] located here:

install-scripts/src/dotnet-install.sh

Line 15 in 033622c

invocation='say_verbose "Calling: ${yellow:-}${FUNCNAME[0]} ${green:-}$*${normal:-}"'

is a Bash specific thing. ZSH uses funcstack, but I'm not sure why it fails only when dot-sourced.