Merge pull request #678 from PowerShell/kapilmb/FixAvoidAliasRule

Fix PSAvoidUsingCmdletAliases false positives in DSC configuration

Author: Kapil Borle

Rules/AvoidAlias.cs

@@ -106,6 +106,13 @@ public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)
             foreach (Ast foundAst in foundAsts)
             {
                 CommandAst cmdAst = (CommandAst)foundAst;
+
+                // Check if the command ast should be ignored
+                if (IgnoreCommandast(cmdAst))
+                {
+                    continue;
+                }
+
                 string aliasName = cmdAst.GetCommandName();
 
                 // Handles the exception caused by commands like, {& $PLINK $args 2> $TempErrorFile}.
@@ -132,6 +139,23 @@ public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)
             }
         }
 
+        /// <summary>
+        /// Checks commandast of the form "[commandElement0] = [CommandElement2]". This typically occurs in a DSC configuration.
+        /// </summary>
+        private bool IgnoreCommandast(CommandAst cmdAst)
+        {
+            if (cmdAst.CommandElements.Count == 3)
+            {
+                var element = cmdAst.CommandElements[1] as StringConstantExpressionAst;
+                if (element != null && element.Value.Equals("="))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         /// <summary>
         /// For a command like "gci -path c:", returns the extent of "gci" in the command
         /// </summary>

Tests/Rules/AvoidUsingAlias.tests.ps1

@@ -1,11 +1,13 @@
-Import-Module PSScriptAnalyzer
-$violationMessage = "'cls' is an alias of 'Clear-Host'. Alias can introduce possible problems and make scripts hard to maintain. Please consider changing alias to its full content."
+$violationMessage = "'cls' is an alias of 'Clear-Host'. Alias can introduce possible problems and make scripts hard to maintain. Please consider changing alias to its full content."
 $violationName = "PSAvoidUsingCmdletAliases"
 $directory = Split-Path -Parent $MyInvocation.MyCommand.Path
+$testRootDirectory = Split-Path -Parent $directory
 $violationFilepath = Join-Path $directory 'AvoidUsingAlias.ps1'
 $violations = Invoke-ScriptAnalyzer $violationFilepath | Where-Object {$_.RuleName -eq $violationName}
 $noViolations = Invoke-ScriptAnalyzer $directory\AvoidUsingAliasNoViolations.ps1 | Where-Object {$_.RuleName -eq $violationName}
-Import-Module (Join-Path $directory "PSScriptAnalyzerTestHelper.psm1")
+
+Import-Module PSScriptAnalyzer
+Import-Module (Join-Path $testRootDirectory "PSScriptAnalyzerTestHelper.psm1")
 
 Describe "AvoidUsingAlias" {
     Context "When there are violations" {
@@ -40,6 +42,22 @@ gci -Path C:\
         It "returns no violations" {
             $noViolations.Count | Should Be 0
         }
+
+        It "should return no violation for assignment statement-like command in dsc configuration" {
+            $target = @'
+Configuration MyDscConfiguration {
+    Node "NodeA" {
+        SomeResource MyResourceInstance {
+            Type = "Present"
+            Name =    "RSAT"
+        }
+    }
+}
+'@
+            Invoke-ScriptAnalyzer -ScriptDefinition $target -IncludeRule $violationName | `
+                Get-Count | `
+                Should Be 0
+        }
     }
 
     Context "Settings file provides whitelist" {