Release D 2.093.0

[Bastiaan Veelo]

On Sunday, 19 July 2020 at 19:16:29 UTC, jmh530 wrote:
> I just upgraded a machine to Linux Mint 20 on a fresh install 
> and tried to run the install script. It fails with
> main: line 178: USERPROFILE: unbound variable
>
> This line should only be called on Windows, which I found 
> strange. It turns out that this is driven by
>
> ```
> posix_terminal() {
>     # If this script is run on Windows cmd by passing it as 
> argument to bash.exe,
>     # the shell level will be 1. If it is run from a POSIX 
> terminal, it will be > 1.
>     if [ "$SHLVL" = 1 ]; then
>         false
>     else
>         true
>     fi
> }
> ```
>
> Running `echo $SHLVL` prints `1`
>
> Running
> ```
> bash
> echo $SHLVL
> ```
> prints `2`
>
>
> Running `echo $SHELL` prints `/bin/bash`
>
> The issue seems to be related to an update to Ubuntu 16:
> https://askubuntu.com/questions/856532/why-is-shlvl-initially-2-in-ubuntu-16-10-but-not-earlier-versions

I don't think it is related to the Ubuntu 16.10 issue, because 
the above test does not rely on SHLVL being 2 initially. If the 
script is called from the terminal, and the terminal is running 
bash (which it seems to do according to the output of $SHELL) 
SHLVL should be at least 1 on the terminal and one higher when 
the script is run (since running a script starts a new bash). 
Maybe the script is run in a way that breaks this assumption? Is 
it run using `call`? Is it run headless, without a terminal? Is 
it not run by real bash?

There is a related conversation here, but not quite the same: 
https://github.com/dlang/installer/commit/e084815001390538bbd6fe5be7c2d4d81ee681b7#commitcomment-40487617

Please open an issue on https://issues.dlang.org/enter_bug.cgi 
and post a link here, if we need to drill deeper.

I can imagine that the current `posix_terminal()` is flawed if 
the terminal is running a shell that is not bash, for which we 
should find a solution.

--Bastiaan.