Build PowerShell on Windows for .NET Core
=========================================

This guide will walk you through building PowerShell on Windows, targeting .NET Core. 
We'll start by showing how to set up your environment from scratch.

You can also [build PowerShell for Full .NET framework](windows-full.md) on Windows.

Environment
===========

These instructions are tested on Windows 10 and Windows Server 2012
R2, though they should work anywhere the dependencies work.

Git Setup
---------

Using Git requires it to be setup correctly; refer to the
[README](../../README.md) and
[Contributing Guidelines](../../.github/CONTRIBUTING.md).

This guide assumes that you have recursively cloned the PowerShell repository and `cd`ed into it.

Visual Studio
----------------

You will need to install an edition of Visual Studio 2015 (Community, Enterprise, or Professional) with the optional feature 'Common Tools for Visual C++' installed. 
The free Community edition of Visual Studio 2015 can be downloaded [here](https://www.visualstudio.com/visual-studio-community-vs/).

.NET CLI
--------

We use the [.NET Command Line Interface][dotnet-cli] (`dotnet`) to build PowerShell.
The `Start-PSBootstrap` function will automatically install it and add it to your path:

```powershell
Import-Module ./build.psm1
Start-PSBootstrap
```

The `Start-PSBootstrap` function itself does exactly this:

```powershell
Invoke-WebRequest -Uri https://raw.githubusercontent.com/dotnet/cli/rel/1.0.0/scripts/obtain/dotnet-install.ps1 -OutFile install.ps1
./install.ps1
```

If you have any problems installing `dotnet`, please see their [documentation][cli-docs].

[dotnet-cli]: https://github.com/dotnet/cli#new-to-net-cli
[cli-docs]: https://dotnet.github.io/getting-started/

Build using our module
======================

We maintain a [PowerShell module](../../build.psm1) with the function `Start-PSBuild` to build PowerShell.

```powershell
Import-Module ./build.psm1
Start-PSBuild
```

Congratulations! If everything went right, PowerShell is now built and executable as `./src/powershell-win-core/bin/Debug/netcoreapp1.0/win10-x64/powershell`.

This location is of the form `./[project]/bin/[configuration]/[framework]/[rid]/[binary name]`, 
and our project is `powershell`, configuration is `Debug` by default, 
framework is `netcoreapp1.1`, runtime identifier is **probably** `win10-x64` 
(but will depend on your operating system; 
don't worry, `dotnet --info` will tell you what it was), and binary name is `powershell`. 
The function `Get-PSOutput` will return the path to the executable; 
thus you can execute the development copy via `& (Get-PSOutput)`.

The `powershell` project is the .NET Core PowerShell host. 
It is the top level project, so `dotnet build` transitively builds all its dependencies, 
and emits a `powershell` executable. 
The cross-platform host has built-in documentation via `--help`.

You can run our cross-platform Pester tests with `Start-PSPester`.

Building in Visual Studio
-----------------------------

We do not recommend building the PowerShell solution from Visual Studio. 
This may lead to package version mismatches with errors similar to:
```
C:\dev\powershell\src\System.Management.Automation\project.json(142,77): error NU1001: The dependency Microsoft.PowerShe
ll.CoreCLR.AssemblyLoadContext >= 1.0.0-* could not be resolved.
```
If you find yourself blocked by these errors, either run `git clean -ffdx` or run `Start-PSBuild -Clean`.