Fix Splatted Variable and Pipeline bug in UseCmdletCorrectly and AvoidPositionalParameter

Author: Quoc Truong

Engine/Helper.cs

@@ -219,6 +219,21 @@ item is TypeDefinitionAst
             return false;
         }
 
+        /// <summary>
+        /// Given a commandast, checks whether it uses splatted variable
+        /// </summary>
+        /// <param name="cmdAst"></param>
+        /// <returns></returns>
+        public bool HasSplattedVariable(CommandAst cmdAst)
+        {
+            if (cmdAst == null || cmdAst.CommandElements == null)
+            {
+                return false;
+            }
+
+            return cmdAst.CommandElements.Any(cmdElem => cmdElem is VariableExpressionAst && (cmdElem as VariableExpressionAst).Splatted);
+        }
+
         /// <summary>
         /// Given a commandast, checks whether positional parameters are used or not.
         /// </summary>
@@ -237,6 +252,11 @@ public bool PositionalParameterUsed(CommandAst cmdAst)
             IEnumerable<CommandParameterSetInfo> scriptBlocks = null;
             bool hasScriptBlockSet = false;
 
+            if (HasSplattedVariable(cmdAst))
+            {
+                return false;
+            }
+
             if (commandInfo != null && commandInfo.CommandType == System.Management.Automation.CommandTypes.Cmdlet)
             {
                 try
@@ -286,19 +306,19 @@ public bool PositionalParameterUsed(CommandAst cmdAst)
                     }
                     else
                     {
-                        //Skip if splatting "@" is used
-                        if (ceAst is VariableExpressionAst)
-                        {
-                            if ((ceAst as VariableExpressionAst).Splatted)
-                            {
-                                continue;
-                            }
-                        }
                         arguments += 1;
                     }
                 }
             }
 
+            // if not the first element in a pipeline, increase the number of arguments by 1
+            PipelineAst parent = cmdAst.Parent as PipelineAst;
+
+            if (parent != null && parent.PipelineElements.Count > 1 && parent.PipelineElements[0] != cmdAst)
+            {
+                arguments += 1;
+            }
+
             return arguments > parameters;
         }
 

Rules/AvoidPositionalParameters.cs

@@ -47,8 +47,23 @@ public IEnumerable<DiagnosticRecord> AnalyzeScript(Ast ast, string fileName)
                 if (Helper.Instance.GetCommandInfo(cmdAst.GetCommandName()) != null
                     && Helper.Instance.PositionalParameterUsed(cmdAst))
                 {
-                    yield return new DiagnosticRecord(string.Format(CultureInfo.CurrentCulture, Strings.AvoidUsingPositionalParametersError, cmdAst.GetCommandName()),
-                        cmdAst.Extent, GetName(), DiagnosticSeverity.Warning, fileName, cmdAst.GetCommandName());
+                    PipelineAst parent = cmdAst.Parent as PipelineAst;
+
+                    if (parent != null && parent.PipelineElements.Count > 1)
+                    {
+                        // raise if it's the first element in pipeline. otherwise no.
+                        if (parent.PipelineElements[0] == cmdAst)
+                        {
+                            yield return new DiagnosticRecord(string.Format(CultureInfo.CurrentCulture, Strings.AvoidUsingPositionalParametersError, cmdAst.GetCommandName()),
+                                cmdAst.Extent, GetName(), DiagnosticSeverity.Warning, fileName, cmdAst.GetCommandName());
+                        }
+                    }
+                    // not in pipeline so just raise it normally
+                    else
+                    {
+                        yield return new DiagnosticRecord(string.Format(CultureInfo.CurrentCulture, Strings.AvoidUsingPositionalParametersError, cmdAst.GetCommandName()),
+                            cmdAst.Extent, GetName(), DiagnosticSeverity.Warning, fileName, cmdAst.GetCommandName());
+                    }
                 }
             }
         }

Rules/UseCmdletCorrectly.cs

@@ -92,6 +92,12 @@ private bool IsMandatoryParameterExisted(CommandAst cmdAst)
                 return true;
             }
 
+            // ignores if splatted variable is used
+            if (Helper.Instance.HasSplattedVariable(cmdAst))
+            {
+                return true;
+            }
+
             // Gets parameters from command elements.
             ceAsts = cmdAst.CommandElements.Where<CommandElementAst>(foundParamASTs);
 

Tests/Rules/GoodCmdlet.ps1

@@ -85,6 +85,12 @@ function Get-File
             $a
         }
 
+        $a | Write-Warning
+
+        $b = @{"hash"="table"}
+
+        Write-Debug @b
+
         return @{"hash"="true"}
     }
     End

Tests/Rules/UseCmdletCorrectly.ps1

@@ -2,4 +2,4 @@
 Wrong-Cmd
 Write-Verbose -Message "Write Verbose"
 Write-Verbose "Warning" -OutVariable $test
-Write-Verbose "Warning"
+Write-Verbose "Warning" | PipeLineCmdlet