aspnetcore/test/Microsoft.AspNetCore.Mvc.Ra.../Compilation/ExpressionRewriterTest.cs

577 lines
18 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Xunit;
namespace Microsoft.AspNetCore.Mvc.Razor.Compilation
{
public class ExpressionRewriterTest
{
[Fact]
public void ExpressionRewriter_DoesNotThrowsOnUnknownTypes()
{
// Arrange
var source = @"
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Razor;
public class ExamplePage : RazorPage
{
public IViewComponentHelper Component { get; set; }
public override async Task ExecuteAsync()
{
Write(
await Component.InvokeAsync(
""SomeComponent"",
item => new HelperResult((__razor_template_writer) => WriteLiteralTo(__razor_template_writer, ""Hello World""))));
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
// Allow errors here because of an anomaly where Roslyn (depending on code sample) will finish compilation
// without diagnostic errors. This test case replicates that scenario by allowing a semantic model with
// errors to be visited by the expression rewriter to validate unexpected exceptions aren't thrown.
// Error created: "Cannot convert lambda expression to type 'object' because it is not a delegate type."
var compilation = Compile(tree, allowErrors: true);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
var root = tree.GetRoot();
// Act
var result = rewriter.Visit(root);
// Assert
Assert.True(root.IsEquivalentTo(result));
}
[Fact]
public void ExpressionRewriter_CanRewriteExpression_IdentityExpression()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<object, object>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x => x);
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var fields = FindFields(result);
var field = Assert.Single(fields);
Assert.Collection(
field.Modifiers,
m => Assert.Equal("private", m.ToString()),
m => Assert.Equal("static", m.ToString()),
m => Assert.Equal("readonly", m.ToString()));
var declaration = field.Declaration;
Assert.Equal(
"global::System.Linq.Expressions.Expression<global::System.Func<object, object>>",
declaration.Type.ToString());
var variable = Assert.Single(declaration.Variables);
Assert.Equal("__h0", variable.Identifier.ToString());
Assert.Equal("x => x", variable.Initializer.Value.ToString());
var arguments = FindArguments(result);
var argument = Assert.IsType<IdentifierNameSyntax>(Assert.Single(arguments.Arguments).Expression);
Assert.Equal("__h0", argument.Identifier.ToString());
}
[Fact]
public void ExpressionRewriter_CanRewriteExpression_MemberAccessExpression()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<Person, object>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x => x.Name);
}
}
public class Person
{
public string Name { get; set; }
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var fields = FindFields(result);
var field = Assert.Single(fields);
Assert.Collection(
field.Modifiers,
m => Assert.Equal("private", m.ToString()),
m => Assert.Equal("static", m.ToString()),
m => Assert.Equal("readonly", m.ToString()));
var declaration = field.Declaration;
Assert.Equal(
"global::System.Linq.Expressions.Expression<global::System.Func<global::Person, object>>",
declaration.Type.ToString());
var variable = Assert.Single(declaration.Variables);
Assert.Equal("__h0", variable.Identifier.ToString());
Assert.Equal("x => x.Name", variable.Initializer.Value.ToString());
var arguments = FindArguments(result);
var argument = Assert.IsType<IdentifierNameSyntax>(Assert.Single(arguments.Arguments).Expression);
Assert.Equal("__h0", argument.Identifier.ToString());
}
[Fact]
public void ExpressionRewriter_CanRewriteExpression_ChainedMemberAccessExpression()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<Person, int>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x => x.Name.Length);
}
}
public class Person
{
public string Name { get; set; }
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var fields = FindFields(result);
var field = Assert.Single(fields);
Assert.Collection(
field.Modifiers,
m => Assert.Equal("private", m.ToString()),
m => Assert.Equal("static", m.ToString()),
m => Assert.Equal("readonly", m.ToString()));
var declaration = field.Declaration;
Assert.Equal(
"global::System.Linq.Expressions.Expression<global::System.Func<global::Person, int>>",
declaration.Type.ToString());
var variable = Assert.Single(declaration.Variables);
Assert.Equal("__h0", variable.Identifier.ToString());
Assert.Equal("x => x.Name.Length", variable.Initializer.Value.ToString());
var arguments = FindArguments(result);
var argument = Assert.IsType<IdentifierNameSyntax>(Assert.Single(arguments.Arguments).Expression);
Assert.Equal("__h0", argument.Identifier.ToString());
}
[Fact]
public void ExpressionRewriter_CannotRewriteExpression_MethodCall()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<object, int>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x => x.GetHashCode());
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
Assert.Empty(FindFields(result));
}
[Fact]
public void ExpressionRewriter_CannotRewriteExpression_NonArgument()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<object, int>> expression)
{
}
public static void Main(string[] args)
{
Expression<Func<object, int>> expr = x => x.GetHashCode();
CalledWithExpression(expr);
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
Assert.Empty(FindFields(result));
}
[Fact]
public void ExpressionRewriter_CannotRewriteExpression_NestedClass()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
private class Nested
{
public static void CalledWithExpression(Expression<Func<object, int>> expression)
{
}
public static void Main(string[] args)
{
Expression<Func<object, int>> expr = x => x.GetHashCode();
CalledWithExpression(expr);
}
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
Assert.Empty(FindFields(result));
}
[Fact]
public void ExpressionRewriter_CanRewriteExpression_AdditionalArguments()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(int x, Expression<Func<object, object>> expression, string name)
{
}
public static void Main(string[] args)
{
CalledWithExpression(5, x => x, ""Billy"");
}
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var fields = FindFields(result);
var field = Assert.Single(fields);
Assert.Collection(
field.Modifiers,
m => Assert.Equal("private", m.ToString()),
m => Assert.Equal("static", m.ToString()),
m => Assert.Equal("readonly", m.ToString()));
var declaration = field.Declaration;
Assert.Equal(
"global::System.Linq.Expressions.Expression<global::System.Func<object, object>>",
declaration.Type.ToString());
var variable = Assert.Single(declaration.Variables);
Assert.Equal("__h0", variable.Identifier.ToString());
Assert.Equal("x => x", variable.Initializer.Value.ToString());
var arguments = FindArguments(result);
Assert.Equal(3, arguments.Arguments.Count);
var argument = Assert.IsType<IdentifierNameSyntax>(arguments.Arguments[1].Expression);
Assert.Equal("__h0", argument.Identifier.ToString());
}
// When we rewrite the expression, we want to maintain the original span as much as possible.
[Fact]
public void ExpressionRewriter_CanRewriteExpression_SimpleFormatting()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<Person, int>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x => x.Name.Length);
}
}
public class Person
{
public string Name { get; set; }
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var originalArguments = FindArguments(tree.GetRoot());
var originalSpan = originalArguments.GetLocation().GetMappedLineSpan();
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var arguments = FindArguments(result);
Assert.Equal(originalSpan, arguments.GetLocation().GetMappedLineSpan());
}
// When we rewrite the expression, we want to maintain the original span as much as possible.
[Fact]
public void ExpressionRewriter_CanRewriteExpression_ComplexFormatting()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(int z, Expression<Func<Person, int>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(
17,
x =>
x.Name.
Length
);
}
}
public class Person
{
public string Name { get; set; }
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var originalArguments = FindArguments(tree.GetRoot());
var originalSpan = originalArguments.GetLocation().GetMappedLineSpan();
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var arguments = FindArguments(result);
Assert.Equal(originalSpan, arguments.GetLocation().GetMappedLineSpan());
}
[Fact]
public void ExpressionRewriter_CanRewriteExpression_BadlyIndentedFormatting()
{
// Arrange
var source = @"
using System;
using System.Linq.Expressions;
public class Program
{
public static void CalledWithExpression(Expression<Func<Person, int>> expression)
{
}
public static void Main(string[] args)
{
CalledWithExpression(x =>
x.Name.
Length);
}
}
public class Person
{
public string Name { get; set; }
}
";
var tree = CSharpSyntaxTree.ParseText(source);
var originalArguments = FindArguments(tree.GetRoot());
var originalSpan = originalArguments.GetLocation().GetMappedLineSpan();
var compilation = Compile(tree);
var semanticModel = compilation.GetSemanticModel(tree, ignoreAccessibility: true);
var rewriter = new ExpressionRewriter(semanticModel);
// Act
var result = rewriter.Visit(tree.GetRoot());
// Assert
var arguments = FindArguments(result);
Assert.Equal(originalSpan, arguments.GetLocation().GetMappedLineSpan());
}
public ArgumentListSyntax FindArguments(SyntaxNode node)
{
return node
.DescendantNodes(n => true)
.Where(n => n.IsKind(SyntaxKind.ArgumentList))
.Cast<ArgumentListSyntax>()
.Single();
}
public IEnumerable<FieldDeclarationSyntax> FindFields(SyntaxNode node)
{
return node
.DescendantNodes(n => true)
.Where(n => n.IsKind(SyntaxKind.FieldDeclaration))
.Cast<FieldDeclarationSyntax>();
}
private CSharpCompilation Compile(SyntaxTree tree, bool allowErrors = false)
{
// Disable 1702 until roslyn turns this off by default
var options = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
.WithSpecificDiagnosticOptions(new Dictionary<string, ReportDiagnostic>
{
{ "CS1701", ReportDiagnostic.Suppress }, // Binding redirects
{ "CS1702", ReportDiagnostic.Suppress },
{ "CS1705", ReportDiagnostic.Suppress }
});
var compilation = CSharpCompilation.Create(
"Test.Assembly",
new[] { tree },
GetReferences(),
options: options);
if (!allowErrors)
{
var diagnostics = compilation.GetDiagnostics();
Assert.True(diagnostics.Length == 0, string.Join(Environment.NewLine, diagnostics));
}
return compilation;
}
private IEnumerable<MetadataReference> GetReferences()
{
var types = new[]
{
typeof(System.Linq.Expressions.Expression),
typeof(string),
};
return types.Select(t => MetadataReference.CreateFromFile(t.GetTypeInfo().Assembly.Location));
}
}
}