[devops] Fix API scan when there are no enabled .NET platforms. (#20477)

tools/devops/automation/scripts/Governance.psm1

@@ -10,6 +10,10 @@ class APIScanConfiguration {
         $vars = [ordered]@{}
         Write-Host "enabledPlatforms: $($this.enabledPlatforms)"
 
+        if ($this.enabledPlatforms.count -eq 0) {
+            return ""
+        }
+
         foreach ($platform in $this.enabledPlatforms) {
             # each platform has its version in an environment variable, we need to get it, this
             # could have been inlined when assigning the dictionary but we want to be cleaner.

tools/devops/automation/templates/common/configure.yml

@@ -88,8 +88,10 @@ steps:
     gci env: | sort | format-table -autosize -wrap
     $apiScanMatrix = Get-APIScanConfiguration -EnabledPlatforms "$Env:CONFIGURE_PLATFORMS_DOTNET_PLATFORMS"
     # compress the json to remove any newlines, because we can't set the variable below if the json has any newlines
-    Write-Host "$apiScanMatrix"
-    $apiScanMatrix = $apiScanMatrix | ConvertFrom-Json | ConvertTo-Json -Compress
+    Write-Host "apiScanMatrix=$apiScanMatrix"
+    if ($apiScanMatrix.length -gt 0) {
+      $apiScanMatrix = $apiScanMatrix | ConvertFrom-Json | ConvertTo-Json -Compress
+    }
     Write-Host "##vso[task.setvariable variable=APISCAN_MATRIX;isOutput=true]$apiScanMatrix"
   name: apiscan_matrix
   displayName: 'Create APIScan matrix'

tools/devops/automation/templates/governance/stage.yml

@@ -31,6 +31,7 @@ stages:
       demands:
       - ImageOverride -equals 1ESPT-Windows2022
 
+    condition: ne(stageDependencies.configure_build.configure.outputs['apiscan_matrix.APISCAN_MATRIX'],'')
     strategy:
       matrix: $[ stageDependencies.configure_build.configure.outputs['apiscan_matrix.APISCAN_MATRIX'] ]