Debug parameter now sets debugpreference to continue

src/System.Management.Automation/engine/MshCommandRuntime.cs

@@ -2922,24 +2922,13 @@ internal ActionPreference DebugPreference
             get
             {
                 if (_isDebugPreferenceSet)
+                {
                     return _debugPreference;
+                }
+
                 if (IsDebugFlagSet)
                 {
-                    if (Debug)
-                    {
-                        // If the host couldn't prompt for the debug action anyways, use 'Continue'.
-                        // This lets hosts still see debug output without having to implement the prompting logic.
-                        if (CBhost.ExternalHost.UI == null)
-                        {
-                            return ActionPreference.Continue;
-                        }
-                        else
-                        {
-                            return ActionPreference.Inquire;
-                        }
-                    }
-                    else
-                        return ActionPreference.SilentlyContinue;
+                    return Debug ? ActionPreference.Continue : ActionPreference.SilentlyContinue;
                 }
 
                 if (!_isDebugPreferenceCached)
@@ -2957,6 +2946,7 @@ internal ActionPreference DebugPreference
 
                     _isDebugPreferenceCached = true;
                 }
+
                 return _debugPreference;
             }
             set

src/System.Management.Automation/engine/runtime/CompiledScriptBlock.cs

@@ -2163,7 +2163,7 @@ private void SetPreferenceVariables()
             if (_commandRuntime.IsDebugFlagSet)
             {
                 _localsTuple.SetPreferenceVariable(PreferenceVariable.Debug,
-                                                   _commandRuntime.Debug ? ActionPreference.Inquire : ActionPreference.SilentlyContinue);
+                                                   _commandRuntime.Debug ? ActionPreference.Continue : ActionPreference.SilentlyContinue);
             }
             if (_commandRuntime.IsVerboseFlagSet)
             {

test/powershell/Language/Scripting/ActionPreference.Tests.ps1

@@ -97,8 +97,8 @@ Describe "Tests for (error, warning, etc) action preference" -Tags "CI" {
         }
 
         It '<switch> does not take precedence over $ErrorActionPreference' -TestCases @(
-            @{switch="-Verbose"},
-            @{switch="-Debug"}
+            @{switch="Verbose"},
+            @{switch="Debug"}
         ) {
             param($switch)
             $ErrorActionPreference = "SilentlyContinue"

test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Debug.Tests.ps1

@@ -16,4 +16,18 @@ Describe "Write-Debug tests" -Tags "CI" {
             $DebugPreference = $origDebugPref
         }
     }
+
+    It "Should not prompt the user" {
+        # This script generates an error if Write-Debug prompts the user
+        # (i.e. if $DebugPreference is set to Inquire, the old v1 way)
+        $p = [Diagnostics.Process]::new()
+        $p.StartInfo.FileName = (Get-Process -Id $PID).Path
+        $encoded = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes("Write-Debug -Message 'A debug message' -Debug"))
+        $p.StartInfo.Arguments = "-EncodedCommand $encoded -ExecutionPolicy Bypass -NoLogo -NonInteractive -NoProfile -OutputFormat text"
+        $p.StartInfo.UseShellExecute = $false
+        $p.StartInfo.RedirectStandardError = $true
+        $p.Start() | Out-Null
+        $out = $p.StandardError.ReadToEnd()
+        $out | Should -BeNullOrEmpty
+    }
 }

test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Stream.Tests.ps1

@@ -10,7 +10,7 @@ Describe "Stream writer tests" -Tags "CI" {
         [CmdletBinding()]
 
         param()
-        If ($PSBoundParameters['Debug']) { $DebugPreference = 'Continue' }
+
         Write-Verbose "Verbose message"
 
         Write-Debug "Debug message"