This commit introduces a hack to ConptyConnection for launching WSL.
When we detect that WSL is being launched (either "wsl" or "wsl.exe",
unqialified or _specifically_ from the current OS's System32 directory),
we will promote the startingDirectory specified at launch time into a
commandline argument.
Why do we want to switch to `--cd`?
With the current design of ConptyConnection and WSL, there are some
significant limitations:
* `startingDirectory` cannot be a WSL path, which forces users to
use weird tricks such as setting the starting directory to
`\\wsl$\Distro\home\user`.
* WSL occasionally fails to launch in time to handle a `\\wsl$` path,
which makes us spawn in a strange location (or no location at all).
(This fix will only address the second one until a WSL update is
released that adds support for `--cd $LINUX_PATH`.)
We will not do the promotion if any of the following are true:
* the commandline contains `--cd` already
* the commandline contains a bare `~`
* This was a commonly-used workaround that forced wsl to start in the
user's home directory. It conflicts with --cd.
* wsl is not spelled properly (`WSL` and `WSL.EXE` are unacceptable)
* an absolute path to wsl outside the system32 directory is provided
We chose the do this trick in the connection layer, the latest possible
point, because it captures the most use cases.
We could have done it earlier, but the options were quite limiting.
They are:
* Generate WSL profiles with startingDirectory set to the home folder
* We can't do this because we do not know the user's home folder
path.
* Generate WSL profiles with `--cd` in them.
* This only works for unmodified profiles.
* This only works for generated profiles.
* Users cannot override the commandline without breaking it.
* Users cannot specify a startingDirectory (!) since the one on the
commandline wins.
* Set a flag on generated WSL profiles to request this trick
* This only works for generated profiles. Users who create their own
WSL profiles couldn't set startingDirectory and have it work the
same.
Patching the commandline, hacky though it may be, seemed to be the most
compatible option. Eventually, we can even support `wt -d ~ wsl`!
## Validation Steps Performed
Manual validation for the following cases:
```c++
// MUST MANGLE
auto a01 = _tryMangleStartingDirectoryForWSL(LR"(wsl)", L"SENTINEL");
auto a02 = _tryMangleStartingDirectoryForWSL(LR"(wsl -d X)", L"SENTINEL");
auto a03 = _tryMangleStartingDirectoryForWSL(LR"(wsl -d X ~/bin/sh)", L"SENTINEL");
auto a04 = _tryMangleStartingDirectoryForWSL(LR"(wsl.exe)", L"SENTINEL");
auto a05 = _tryMangleStartingDirectoryForWSL(LR"(wsl.exe -d X)", L"SENTINEL");
auto a06 = _tryMangleStartingDirectoryForWSL(LR"(wsl.exe -d X ~/bin/sh)", L"SENTINEL");
auto a07 = _tryMangleStartingDirectoryForWSL(LR"("wsl")", L"SENTINEL");
auto a08 = _tryMangleStartingDirectoryForWSL(LR"("wsl.exe")", L"SENTINEL");
auto a09 = _tryMangleStartingDirectoryForWSL(LR"("wsl" -d X)", L"SENTINEL");
auto a10 = _tryMangleStartingDirectoryForWSL(LR"("wsl.exe" -d X)", L"SENTINEL");
auto a11 = _tryMangleStartingDirectoryForWSL(LR"("C:\Windows\system32\wsl.exe" -d X)", L"SENTINEL");
auto a12 = _tryMangleStartingDirectoryForWSL(LR"("C:\windows\system32\wsl" -d X)", L"SENTINEL");
auto a13 = _tryMangleStartingDirectoryForWSL(LR"(wsl ~/bin)", L"SENTINEL");
// MUST NOT MANGLE
auto a14 = _tryMangleStartingDirectoryForWSL(LR"("C:\wsl.exe" -d X)", L"SENTINEL");
auto a15 = _tryMangleStartingDirectoryForWSL(LR"(C:\wsl.exe)", L"SENTINEL");
auto a16 = _tryMangleStartingDirectoryForWSL(LR"(wsl --cd C:\)", L"SENTINEL");
auto a17 = _tryMangleStartingDirectoryForWSL(LR"(wsl ~)", L"SENTINEL");
auto a18 = _tryMangleStartingDirectoryForWSL(LR"(wsl ~ -d Ubuntu)", L"SENTINEL");
```
We don't have anywhere to put TerminalConnection unit tests :|
Closes#592.
a2a605050f