Update script to automatically take new preview pre-release builds (PowerShell#17375)

Author: adityapatwardhan

DotnetRuntimeMetadata.json

@@ -1,11 +1,11 @@
 {
   "sdk": {
     "channel": "7.0.1xx-preview4",
-    "quality": "signed",
-    "qualityFallback": "daily",
+    "quality": "daily",
+    "qualityFallback": "preview",
     "packageVersionPattern": "7.0.0-preview.4",
     "sdkImageVersion": "7.0.100",
-    "nextChannel": "7.0.1xx-preview4",
+    "nextChannel": "7.0.1xx",
     "azureFeed": "",
     "sdkImageOverride": ""
   },

tools/UpdateDotnetRuntime.ps1

@@ -254,6 +254,27 @@ function Update-DevContainer {
     $devContainerDocker | Out-File -FilePath $dockerFilePath -Force
 }
 
+<#
+ .DESCRIPTION Update the DotnetMetadata.json file with the latest version of the SDK
+ #>
+function Update-DotnetRuntimeMetadataChannel {
+    param (
+        [string] $newSdk
+    )
+
+    # -replace uses regex so in order to split on `.`, we need to use `\.` to escape the dot character.
+    $sdkParts = $newSdk -split '\.'
+
+    # Transform SDK Version '7.0.100-preview.5.22263.22' -> '7.0.1xx-preview5'
+    $newChannel = $sdkParts[0] + "." + $sdkParts[1] + "." + ($sdkParts[2] -replace '0','x') + $sdkParts[3]
+
+    Write-Verbose -Verbose -Message "Updating DotnetRuntimeMetadata.json with channel $newChannel"
+
+    $metadata = Get-Content -Raw "$PSScriptRoot/../DotnetRuntimeMetadata.json" | ConvertFrom-Json
+    $metadata.sdk.channel = $newChannel
+    $metadata | ConvertTo-Json | Out-File -FilePath "$PSScriptRoot/../DotnetRuntimeMetadata.json" -Force
+}
+
 $dotnetMetadataPath = "$PSScriptRoot/../DotnetRuntimeMetadata.json"
 $dotnetMetadataJson = Get-Content $dotnetMetadataPath -Raw | ConvertFrom-Json
 $channel = $dotnetMetadataJson.sdk.channel
@@ -364,6 +385,8 @@ if ($dotnetUpdate.ShouldUpdate) {
     }
 
     Update-DevContainer
+
+    Update-DotnetRuntimeMetadataChannel -newSdk $latestSdkVersion
 }
 else {
     Write-Verbose -Verbose -Message $dotnetUpdate.Message