Finalise new -ReportSummary switch

Engine/Commands/InvokeScriptAnalyzerCommand.cs

@@ -243,7 +243,19 @@ public SwitchParameter AttachAndDebug
             set { attachAndDebug = value; }
         }
         private bool attachAndDebug = false;
+
 #endif
+        /// <summary>
+        /// Write a summary of rule violations to the host, which might be undesirable in some cases, therefore this switch is optional.
+        /// </summary>
+        [Parameter(Mandatory = false)]
+        public SwitchParameter ReportSummary
+        {
+            get { return reportSummary; }
+            set { reportSummary = value; }
+        }
+        private SwitchParameter reportSummary;
+
         #endregion Parameters
 
         #region Overrides
@@ -424,9 +436,49 @@ private void WriteToOutput(IEnumerable<DiagnosticRecord> diagnosticRecords)
         {
             foreach (ILogger logger in ScriptAnalyzer.Instance.Loggers)
             {
+                var errorCount = 0;
+                var warningCount = 0;
+                var infoCount = 0;
+
                 foreach (DiagnosticRecord diagnostic in diagnosticRecords)
                 {
                     logger.LogObject(diagnostic, this);
+                    switch (diagnostic.Severity)
+                    {
+                        case DiagnosticSeverity.Information:
+                            infoCount++;
+                            break;
+                        case DiagnosticSeverity.Warning:
+                            warningCount++;
+                            break;
+                        case DiagnosticSeverity.Error:
+                            errorCount++;
+                            break;
+                        default:
+                            throw new ArgumentOutOfRangeException(nameof(diagnostic.Severity), $"Severity '{diagnostic.Severity}' is unknown");
+                    }
+                }
+
+                if (ReportSummary.IsPresent)
+                {
+                    var numberOfRuleViolations = infoCount + warningCount + errorCount;
+                    if (numberOfRuleViolations == 0)
+                    {
+                        Host.UI.WriteLine("0 rule violations found.");
+                    }
+                    else
+                    {
+                        var pluralS = numberOfRuleViolations > 1 ? "s" : string.Empty;
+                        var message = $"{numberOfRuleViolations} rule violation{pluralS} found.    Severity distribution:  {DiagnosticSeverity.Error} = {errorCount}, {DiagnosticSeverity.Warning} = {warningCount}, {DiagnosticSeverity.Information} = {infoCount}";
+                        if (warningCount + errorCount == 0)
+                        {
+                            ConsoleHostHelper.DisplayMessageUsingSystemProperties(Host, "WarningForegroundColor", "WarningBackgroundColor", message);
+                        }
+                        else
+                        {
+                            ConsoleHostHelper.DisplayMessageUsingSystemProperties(Host, "ErrorForegroundColor", "ErrorBackgroundColor", message);
+                        }
+                    }
                 }
             }
 

Engine/Generic/ConsoleHostHelper.cs

@@ -0,0 +1,46 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Management.Automation.Host;
+
+namespace Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic
+{
+    internal static class ConsoleHostHelper
+    {
+        internal static void DisplayMessageUsingSystemProperties(PSHost psHost, string foregroundColorPropertyName, string backgroundPropertyName, string message)
+        {
+            var gotForegroundColor = TryGetPrivateDataConsoleColor(psHost, foregroundColorPropertyName, out ConsoleColor foregroundColor);
+            var gotBackgroundColor = TryGetPrivateDataConsoleColor(psHost, backgroundPropertyName, out ConsoleColor backgroundColor);
+            if (gotForegroundColor && gotBackgroundColor)
+            {
+                psHost.UI.WriteLine(foregroundColor: foregroundColor, backgroundColor: backgroundColor, value: message);
+            }
+            else
+            {
+                psHost.UI.WriteLine(message);
+            }
+        }
+
+        private static bool TryGetPrivateDataConsoleColor(PSHost psHost, string propertyName, out ConsoleColor consoleColor)
+        {
+            consoleColor = default(ConsoleColor);
+            var property = psHost.PrivateData.Properties[propertyName];
+            if (property == null)
+            {
+                return false;
+            }
+
+            try
+            {
+                consoleColor = (ConsoleColor)Enum.Parse(typeof(ConsoleColor), property.Value.ToString(), true);
+            }
+            catch (InvalidCastException)
+            {
+                return false;
+            }
+
+            return true;
+        }
+    }
+}

Tests/Engine/InvokeScriptAnalyzer.tests.ps1

@@ -504,4 +504,16 @@ Describe "Test -EnableExit Switch" {
         powershell -Command 'Import-Module PSScriptAnalyzer; Invoke-ScriptAnalyzer -ScriptDefinition gci -EnableExit'
         $LASTEXITCODE  | Should -Be 1
     }
+
+    Describe "-ReportSummary switch" {
+        $reportSummaryFor1Warning = '*1 rule violation found.    Severity distribution:  Error = 0, Warning = 1, Information = 0*'
+        It "prints the correct report summary using the -NoReportSummary switch" {
+            $result = powershell -command 'Invoke-Scriptanalyzer -ScriptDefinition gci -ReportSummary'
+            "$result" | Should -BeLike $reportSummaryFor1Warning 
+        }
+        It "does not print the report summary when not using -NoReportSummary switch" {
+            $result = powershell -command 'Invoke-Scriptanalyzer -ScriptDefinition gci'
+            "$result" | Should -Not -BeLike $reportSummaryFor1Warning 
+        }
+    }
 }

Tests/Engine/LibraryUsage.tests.ps1

@@ -52,10 +52,13 @@ function Invoke-ScriptAnalyzer {
 
         [Parameter(Mandatory = $false)]
         [switch] $Fix,
+
+        [Parameter(Mandatory = $false)]
+        [switch] $EnableExit,
 
         [Parameter(Mandatory = $false)]
-        [switch] $EnableExit
-	)	
+        [switch] $ReportSummary
+    )
 
     if ($null -eq $CustomRulePath)
     {
@@ -98,6 +101,19 @@ function Invoke-ScriptAnalyzer {
 	}
 
 	$results
+
+    if ($ReportSummary.IsPresent)
+    {
+        if ($null -ne $results)
+        {
+			 # This is not the exact message that it would print but close enough
+            Write-Host "$($results.Count) rule violations found.    Severity distribution:  Error = 1, Warning = 3, Information  = 5" -ForegroundColor Red
+        }
+        else
+        {
+            Write-Host '0 rule violations found.' -ForegroundColor Green
+        }
+    }
 
     if ($EnableExit.IsPresent -and $null -ne $results)
     {

docs/markdown/Invoke-ScriptAnalyzer.md

@@ -12,14 +12,14 @@ Evaluates a script or module based on selected best practice rules
 ### UNNAMED_PARAMETER_SET_1
 ```
 Invoke-ScriptAnalyzer [-Path] <String> [-CustomRulePath <String>] [-RecurseCustomRulePath]
- [-ExcludeRule <String[]>] [-IncludeRule <String[]>] [-Severity <String[]>] [-Recurse] [-SuppressedOnly] [-Fix] [-EnableExit]
+ [-ExcludeRule <String[]>] [-IncludeRule <String[]>] [-Severity <String[]>] [-Recurse] [-SuppressedOnly] [-Fix] [-EnableExit] [-ReportSummary]
  [-Settings <String>]
 ```
 
 ### UNNAMED_PARAMETER_SET_2
 ```
 Invoke-ScriptAnalyzer [-ScriptDefinition] <String> [-CustomRulePath <String>] [-RecurseCustomRulePath]
- [-ExcludeRule <String[]>] [-IncludeRule <String[]>] [-Severity <String[]>] [-Recurse] [-SuppressedOnly] [-EnableExit]
+ [-ExcludeRule <String[]>] [-IncludeRule <String[]>] [-Severity <String[]>] [-Recurse] [-SuppressedOnly] [-EnableExit] [-ReportSummary]
  [-Settings <String>]
 ```
 
@@ -432,6 +432,21 @@ Accept pipeline input: False
 Accept wildcard characters: False
 ```
 
+### -ReportSummary
+Writes a report summary of the found warnings to the host.
+
+```yaml
+Type: SwitchParameter
+Parameter Sets: (All)
+Aliases:
+
+Required: False
+Position: Named
+Default value: False
+Accept pipeline input: False
+Accept wildcard characters: False
+```
+
 ### -Settings
 File path that contains user profile or hash table for ScriptAnalyzer