feat: use built-in Newtonsoft.Json if possible

FeatureFlags.psm1

@@ -1,3 +1,4 @@
+$ErrorActionPreference = "Stop"
 <#
 .SYNOPSIS 
 Loads the feature flags configuration from a JSON file.
@@ -18,28 +19,38 @@ function Get-FeatureFlagConfigFromFile([string]$jsonConfigPath) {
 }
 
 # This library uses Test-Json for JSON schema validation for PowerShell >= 6.1.
-# For previous versions, it uses NJsonSchema, # which depends on Newtonsoft.JSON.
+# For previous versions, it uses NJsonSchema, which depends on Newtonsoft.JSON.
 # Since PowerShell itself uses NJsonSchema and Newtonsoft.JSON, we load these
 # assemblies only when it is needed (older PowerShell versions).
 $version = $PSVersionTable.PSVersion
 Write-Verbose "Running under PowerShell $version"
 if ($version -lt [System.Version]"6.1.0") {
  Write-Verbose "Loading JSON/JSON Schema libraries"
- # Import the JSON and JSON schema libraries, and load the JSON schema.
- $libs = Get-ChildItem -Recurse -Path "$PSScriptRoot/External"
- $libs = $libs | Where-Object {$_.Extension -ieq ".dll" -and $_.FullName -ilike "*netstandard1.0*"} | ForEach-Object {$_.FullName}
- $schemaLibPath = $libs | Where-Object {$_ -ilike "*NJsonSchema.dll"}
- if (-not (Test-Path -Path $schemaLibPath -PathType Leaf)) {
- Write-Error "Could not find the DLL for NJSonSchema: $schemaLibPath"
- }
- Write-Verbose "Found NJsonSchema assembly at $schemaLibPath"
 
- $jsonLibPath = $libs | Where-Object {$_ -ilike "*Newtonsoft.Json.dll"}
- if (-not (Test-Path -Path $jsonLibPath -PathType Leaf)) {
- Write-Error "Could not find the DLL for Newtonsoft.Json: $jsonLibPath"
+ # Get DLLs imported via restore.
+ $externalLibs = Get-ChildItem -Recurse -Path "$PSScriptRoot/External"
+ $externalLibs = $externalLibs | Where-Object {$_.Extension -ieq ".dll" -and $_.FullName -ilike "*netstandard1.0*"} | ForEach-Object {$_.FullName}
+
+ # If PowerShell ships with Newtonsoft.JSON, let's load that copy rather than the one in the NuGet package.
+ $jsonLibPath = [System.AppDomain]::CurrentDomain.GetAssemblies() | Where-Object {$_.FullName.StartsWith("Newtonsoft.Json")} | Select-Object -ExpandProperty Location
+ if ($null -eq $jsonLibPath) {
+ $jsonLibPath = $externalLibs | Where-Object {$_ -ilike "*Newtonsoft.Json.dll"}
+
+ if (-not (Test-Path -Path $jsonLibPath -PathType Leaf)) {
+ Write-Error "Could not find the DLL for Newtonsoft.Json: $jsonLibPath"
+ } 
+
+ try {
+ $jsonType = Add-Type -Path $jsonLibPath -PassThru
+ Write-Verbose "JSON.Net type: $jsonType"
+ } catch {
+ Write-Error "Error loading Newtonsoft.Json libraries ($jsonLibPath): $($_.Exception.Message)"
+ throw
+ } 
  }
- Write-Verbose "Found JSON.Net assembly at $jsonLibPath"
+ Write-Verbose "Using Newtonsoft.JSON from $jsonLibPath"
 
+ # Add an assembly redirect in case that NJsonSchema refers to a different version of Newtonsoft.Json.
  Write-Verbose "Adding assembly resolver."
  $onAssemblyResolve = [System.ResolveEventHandler] {
  param($sender, $e)
@@ -54,13 +65,18 @@ if ($version -lt [System.Version]"6.1.0") {
  }
  [System.AppDomain]::CurrentDomain.add_AssemblyResolve($onAssemblyResolve)
 
+ # Load the JSON Schema library.
+ $schemaLibPath = $externalLibs | Where-Object {$_ -ilike "*NJsonSchema.dll"}
+ if (-not (Test-Path -Path $schemaLibPath -PathType Leaf)) {
+ Write-Error "Could not find the DLL for NJSonSchema: $schemaLibPath"
+ }
+ Write-Verbose "Found NJsonSchema assembly at $schemaLibPath"
+
  try {
- $jsonType = Add-Type -Path $jsonLibPath -PassThru
  $jsonSchemaType = Add-Type -Path $schemaLibPath -PassThru
- #Write-Verbose "JSON.Net type: $jsonType"
- #Write-Verbose "NjsonSchema type: $jsonSchemaType"
+ Write-Verbose "NjsonSchema type: $jsonSchemaType"
  } catch {
- Write-Error "Error loading JSON libraries ($jsonLibPath, $schemaLibPath): $($_.Exception.Message)"
+ Write-Error "Error loading JSON schema library ($schemaLibPath): $($_.Exception.Message)"
  throw
  }
 
@@ -467,4 +483,4 @@ function Out-FeaturesEnvConfig
  }
  }
  }
-}
+}