Create Start-PSRelease helper function (#2753)

build.psm1

@@ -1117,6 +1117,71 @@ function Start-PSBootstrap {
     }
 }
 
+function Start-PSRelease {
+    [CmdletBinding()]
+    param(
+        [Parameter(Mandatory)]
+        [string]$Name, # i.e. v6.0.0-alpha.12
+        [Parameter(Mandatory)]
+        [string]$CommitSHA1 # i.e. 7985366f9ec43af47b24dd88f04c0afc5eab3825
+    )
+
+    Push-Location $PSScriptRoot
+    try {
+        # check that we are in the right location
+        if ($IsWindows) {
+            if ($PSScriptRoot -ne "C:\PowerShell") {
+                throw "To make the release, please clone the project to C:\PowerShell. Currently it's under $PSScriptRoot"
+            }
+        } else {
+            if ($PSScriptRoot -ne "/PowerShell") {
+                throw "To make the release, please clone the project to /PowerShell. Currently it's under $PSScriptRoot"
+            }
+        }
+
+        # check that there is no tag with $Name yet
+        if ((git tag) -eq $Name) {
+            throw "Tag $Name already exists"
+        }
+
+        if ((git rev-parse HEAD) -ne $CommitSHA1) {
+            throw "Checkout the release commit before making the release: git checkout $CommitSHA1"
+        }
+
+        # Check that there are any local changes
+        $changedFiles = git status --porcelain -uno
+        if ($changedFiles) {
+            throw "There are changes in: $changedFiles"
+        }
+
+        $untrackedFiles = git ls-files --other --exclude-standard --directory
+        if ($untrackedFiles) {
+            throw "There are untracked files (run 'git clean -fdx'): $untrackedFiles"
+        }
+
+        # make sure submodules are up-to-date
+        git submodule init
+        git submodule update
+
+        # Create temporarely release tag
+        (git tag $Name $CommitSHA1)
+
+        try {
+            # make sure that we have up-to-date version of build tools
+            Start-PSBootstrap -Package
+            # run the clean build that will use temporarely tag
+            Start-PSBuild -Clean -Crossgen -PSModuleRestore
+            # make the package
+            Start-PSPackage
+        } finally {
+            # cleanup temporarely tag
+            git tag -d $Name
+        }
+    } finally {
+        Pop-Location
+    }
+}
+
 
 function Start-PSPackage {
     [CmdletBinding()]param(