[CodeIssues] Add ExceptionRethrowIssue

ICSharpCode.NRefactory.CSharp/ICSharpCode.NRefactory.CSharp.csproj

@@ -426,6 +426,7 @@
     <Compile Include="Refactoring\CodeIssues\FormatStringIssues\FormatStringIssue.cs" />
     <Compile Include="Refactoring\CodeIssues\FormatStringIssues\FormatStringHelper.cs" />
     <Compile Include="Refactoring\CodeActions\ConvertToInitializer\ConvertInitializerToExplicitInitializationsAction.cs" />
+    <Compile Include="Refactoring\CodeIssues\ExceptionRethrowIssue.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\ICSharpCode.NRefactory\ICSharpCode.NRefactory.csproj">

ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/ExceptionRethrowIssue.cs

@@ -0,0 +1,130 @@
+//
+// ExceptionRethrowIssue.cs
+//
+// Author:
+//       Simon Lindgren <simon.n.lindgren@gmail.com>
+//
+// Copyright (c) 2012 Simon Lindgren
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+using System;
+using System.Collections.Generic;
+using ICSharpCode.NRefactory.TypeSystem;
+using ICSharpCode.NRefactory.Semantics;
+
+namespace ICSharpCode.NRefactory.CSharp.Refactoring
+{
+	[IssueDescription("A throw statement throws the caught exception by passing it explicitly",
+	                  Description = "Finds throws that throws the caught exception and therefore should be empty.",
+	                  Category = IssueCategories.CodeQualityIssues,
+	                  Severity = Severity.Warning)]
+	public class ExceptionRethrowIssue : ICodeIssueProvider
+	{
+		public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
+		{
+			return new GatherVisitor(context).GetIssues();
+		}
+		
+		class GatherVisitor : GatherVisitorBase
+		{
+			public GatherVisitor(BaseRefactoringContext context) : base (context)
+			{
+			}
+			
+			public override void VisitCatchClause(CatchClause catchClause)
+			{
+				base.VisitCatchClause(catchClause);
+				var exceptionResolveResult = ctx.Resolve(catchClause.VariableNameToken) as LocalResolveResult;
+				if (exceptionResolveResult == null)
+					return;
+
+				var catchVisitor = new CatchClauseVisitor(ctx, exceptionResolveResult.Variable);
+				catchClause.Body.AcceptVisitor(catchVisitor);
+
+				foreach (var throwStatement in catchVisitor.OffendingThrows) {
+					var localThrowStatement = throwStatement;
+					var title = ctx.TranslateString("The exception is rethrown with explicit usage of the variable");
+					var action = new CodeAction(ctx.TranslateString("Change to 'throw;'"), script => {
+						script.Replace(localThrowStatement, new ThrowStatement());
+					});
+					AddIssue(localThrowStatement, title, new [] { action });
+				}
+			}
+		}
+		
+		class CatchClauseVisitor : DepthFirstAstVisitor
+		{
+			BaseRefactoringContext ctx;
+
+			IVariable parameter;
+
+			bool variableWritten = false;
+
+			public CatchClauseVisitor(BaseRefactoringContext context, IVariable parameter)
+			{
+				ctx = context;
+				this.parameter = parameter;
+				OffendingThrows = new List<ThrowStatement>();
+			}
+
+			public IList<ThrowStatement> OffendingThrows { get; private set; }
+
+			void HandlePotentialWrite (Expression expression)
+			{
+				var variableResolveResult = ctx.Resolve(expression) as LocalResolveResult;
+				if (variableResolveResult == null)
+					return;
+				variableWritten |= variableResolveResult.Equals(parameter);
+			}
+
+			public override void VisitAssignmentExpression(AssignmentExpression assignmentExpression)
+			{
+				base.VisitAssignmentExpression(assignmentExpression);
+
+				var variableResolveResult = ctx.Resolve(assignmentExpression.Left) as LocalResolveResult;
+				if (variableResolveResult == null)
+					return;
+				variableWritten |= variableResolveResult.Variable.Equals(parameter);
+			}
+
+			public override void VisitDirectionExpression(DirectionExpression directionExpression)
+			{
+				base.VisitDirectionExpression(directionExpression);
+
+				HandlePotentialWrite(directionExpression);
+			}
+
+			public override void VisitThrowStatement(ThrowStatement throwStatement)
+			{
+				base.VisitThrowStatement(throwStatement);
+
+				if (variableWritten)
+					return;
+
+				var argumentResolveResult = ctx.Resolve(throwStatement.Expression) as LocalResolveResult;
+				if (argumentResolveResult == null)
+					return;
+				if (parameter.Equals(argumentResolveResult.Variable))
+					OffendingThrows.Add(throwStatement);
+			}
+		}
+		
+	}
+}
+

ICSharpCode.NRefactory.Tests/CSharp/CodeIssues/ExceptionRethrowTests.cs

@@ -0,0 +1,88 @@
+//
+// ExceptionRethrowIssue.cs
+//
+// Author:
+//       Simon Lindgren <simon.n.lindgren@gmail.com>
+//
+// Copyright (c) 2012 Simon Lindgren
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+using System;
+using NUnit.Framework;
+using ICSharpCode.NRefactory.CSharp.CodeActions;
+using ICSharpCode.NRefactory.CSharp.Refactoring;
+
+namespace ICSharpCode.NRefactory.CSharp.CodeIssues
+{
+	public class ExceptionRethrowTests : InspectionActionTestBase
+	{
+		[Test]
+		public void BasicCase ()
+		{
+			var input = @"
+class Foo
+{
+	void Bar (int i)
+	{
+		try {}
+		catch (Exception e) {
+			throw e;
+		}
+	}
+}";
+
+			TestRefactoringContext context;
+			var issues = GetIssues (new ExceptionRethrowIssue (), input, out context);
+			Assert.AreEqual (1, issues.Count);
+			CheckFix (context, issues, @"
+class Foo
+{
+	void Bar (int i)
+	{
+		try {}
+		catch (Exception e) {
+			throw;
+		}
+	}
+}");
+		}
+
+		[Test]
+		public void HandlesSimpleWriteToVariable ()
+		{
+			var input = @"
+class Foo
+{
+	void Bar (int i)
+	{
+		try {}
+		catch (Exception e) {
+			e = new Exception(e);
+			throw e;
+		}
+	}
+}";
+			
+			TestRefactoringContext context;
+			var issues = GetIssues (new ExceptionRethrowIssue (), input, out context);
+			Assert.AreEqual (0, issues.Count);
+		}
+	}
+}
+

ICSharpCode.NRefactory.Tests/ICSharpCode.NRefactory.Tests.csproj

@@ -341,6 +341,7 @@
     <Compile Include="CSharp\CodeIssues\FormatStringIssues\FormatStringTests.cs" />
     <Compile Include="CSharp\CodeActions\ConvertToInitializer\ConvertInitializerToExplicitIntializationsTests.cs" />
     <Compile Include="CSharp\CodeCompletion\BrowsableAttributeTests.cs" />
+    <Compile Include="CSharp\CodeIssues\ExceptionRethrowTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Mono.Cecil\Mono.Cecil.csproj">