Currently, dotnet will crash with an `ArgumentNullException` if `USERPROFILE`
(Windows) or `HOME` (macOS and Linux) is not set in the environment. This
is because there is a missing null check after retrieving the environment
variable's value. Additionally, if either variable is set to an empty string,
a `.dotnet` directory is created in the current directory where dotnet is being
run.
This commit fixes this by printing a graceful error informing the user the home
directory could not be determined and to set `DOTNET_CLI_HOME` to the directory
to use. This variable will be respected before `USERPROFILE` or `HOME`. It is
likely that CI environments where `HOME` is not set can use `DOTNET_CLI_HOME`
to specify a local temporary location; by using this variable rather than
setting `HOME`, it is guaranteed to only affect dotnet.
It was discussed that we should perhaps fallback to some temporary location if
the home directory could not be determined, but NuGet currently requires `HOME`
to be set to work. Because of this, it was decided that we should just handle
this case gracefully and provide a way for users to override the home directory
without relying on `USERPROFILE`/`HOME` entirely.
Closes#8053.
This commit attempts to make the command line help user experience for `dotnet`
more consistent for all of the built-in SDK commands.
The following has been changed:
* Organized the top-level help into a section detailing how to run .NET
applications and a section on running SDK commands.
* Sorted the SDK commands by name (previous ordering was undefined).
* Removed `--verbosity` from the "common options section" since it is not a
top-level option, nor is it common to all commands.
* Added missing parameter names for parameterized options (especially for the
`dotnet tool` subcommands).
* Fixed the localization of parameter names for parameterized options.
* Added missing `PROJECT` parameter to a few commands.
* Fixed the localization of the build command's `PROJECT` parameter description.
* Fixed the confusing descriptions for the `--framework`, `--configuration`,
and `--runtime` options that were being shared between different commands.
* Fixed the "unknown command" error for `dotnet help <command>` to show in red.
* Deleted .resx for `dotnet msbuild` that is no longer used.
* Change the option descriptions to be more consistent in their grammatical
structure.
* Removed extra blank line from end of help output.
Fixes#7431.
Fixes#9230.
Fixes#9165.
