From 0bac8b180b0d436e50091b27c72ce15c6bef46cd Mon Sep 17 00:00:00 2001
From: Liviu Uba <liviu.uba@uipath.com>
Date: Sat, 18 Feb 2023 15:49:13 +0200
Subject: [PATCH] feat(roslyn): extensibility

- make GetMetadataReferencesForExpression virtual.
- publish resolved identifiers for descendant classes
---
 .../Activities/CsExpressionValidator.cs                |  7 +++++--
 src/UiPath.Workflow/Activities/ExpressionContainer.cs  |  5 +++++
 .../Activities/RoslynExpressionValidator.cs            | 10 ++++++----
 .../Activities/VbExpressionValidator.cs                |  8 ++++++--
 4 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/UiPath.Workflow/Activities/CsExpressionValidator.cs b/src/UiPath.Workflow/Activities/CsExpressionValidator.cs
index 0e1b27f9..8edab133 100644
--- a/src/UiPath.Workflow/Activities/CsExpressionValidator.cs
+++ b/src/UiPath.Workflow/Activities/CsExpressionValidator.cs
@@ -100,8 +100,11 @@ protected override void UpdateCompilationUnit(ExpressionContainer expressionCont
         }
     }
 
-    protected override string CreateValidationCode(string types, string names, string code) => 
-        $"public static Expression<Func<{types}>> CreateExpression() => ({names}) => {code};";
+    protected override string CreateValidationCode(string types, string names, ExpressionContainer expressionContainer)
+    {
+        var code = expressionContainer.ExpressionToValidate.Code;
+        return $"public static Expression<Func<{types}>> CreateExpression() => ({names}) => {code};";
+    }
 
     protected override SyntaxTree GetSyntaxTreeForExpression(ExpressionContainer expressionContainer) => 
         CSharpSyntaxTree.ParseText(expressionContainer.ExpressionToValidate.Code, s_csScriptParseOptions);
diff --git a/src/UiPath.Workflow/Activities/ExpressionContainer.cs b/src/UiPath.Workflow/Activities/ExpressionContainer.cs
index 536d4094..7fb34479 100644
--- a/src/UiPath.Workflow/Activities/ExpressionContainer.cs
+++ b/src/UiPath.Workflow/Activities/ExpressionContainer.cs
@@ -44,4 +44,9 @@ public class ExpressionContainer
     ///     Diagnostics reported by validating the expression.
     /// </summary>
     public IEnumerable<TextExpressionCompilerError> Diagnostics { get; set; }
+
+    /// <summary>
+    /// populated before CreateValidationCode step
+    /// </summary>
+    public (string Name, Type Type)[] ResolvedIdentifiers { get; set; }
 }
diff --git a/src/UiPath.Workflow/Activities/RoslynExpressionValidator.cs b/src/UiPath.Workflow/Activities/RoslynExpressionValidator.cs
index ca34a3b2..68f7630a 100644
--- a/src/UiPath.Workflow/Activities/RoslynExpressionValidator.cs
+++ b/src/UiPath.Workflow/Activities/RoslynExpressionValidator.cs
@@ -90,7 +90,7 @@ public void AddRequiredAssembly(Assembly assembly)
     /// </summary>
     /// <param name="expressionContainer">expression container</param>
     /// <returns>MetadataReference objects for all required assemblies</returns>
-    protected IEnumerable<MetadataReference> GetMetadataReferencesForExpression(ExpressionContainer expressionContainer) =>
+    protected virtual IEnumerable<MetadataReference> GetMetadataReferencesForExpression(ExpressionContainer expressionContainer) =>
         expressionContainer.RequiredAssemblies.Select(asm => TryGetMetadataReference(asm)).Where(mr => mr is not null);
 
     /// <summary>
@@ -107,7 +107,7 @@ protected IEnumerable<MetadataReference> GetMetadataReferencesForExpression(Expr
     /// <param name="names">list of parameter names in comma-separated string</param>
     /// <param name="code">expression code</param>
     /// <returns>expression wrapped in a method or function that returns a LambdaExpression</returns>
-    protected abstract string CreateValidationCode(string types, string names, string code);
+    protected abstract string CreateValidationCode(string types, string names, ExpressionContainer expressionContainer);
 
     /// <summary>
     ///     Updates the <see cref="Compilation" /> object for the expression.
@@ -180,7 +180,7 @@ public virtual IEnumerable<ValidationError> Validate<TResult>(Activity currentAc
         var diagnostics = expressionContainer
             .CompilationUnit
             .GetDiagnostics()
-            .Where(d=> d.Severity == DiagnosticSeverity.Error)
+            .Where(d => d.Severity == DiagnosticSeverity.Error)
             .Select(diagnostic =>
             new TextExpressionCompilerError
             {
@@ -269,6 +269,8 @@ private void PrepValidation(ExpressionContainer expressionContainer)
                 .Where(var => var.Type != null)
                 .ToArray();
 
+        expressionContainer.ResolvedIdentifiers = resolvedIdentifiers;
+
         var names = string.Join(Comma, resolvedIdentifiers.Select(var => var.Name));
         var types = string.Join(Comma,
             resolvedIdentifiers
@@ -276,7 +278,7 @@ private void PrepValidation(ExpressionContainer expressionContainer)
                 .Concat(new[] { expressionContainer.ResultType })
                 .Select(GetTypeName));
 
-        var lambdaFuncCode = CreateValidationCode(types, names, expressionContainer.ExpressionToValidate.Code);
+        var lambdaFuncCode = CreateValidationCode(types, names, expressionContainer);
         var sourceText = SourceText.From(lambdaFuncCode);
         var newSyntaxTree = syntaxTree.WithChangedText(sourceText);
         expressionContainer.CompilationUnit = expressionContainer.CompilationUnit.ReplaceSyntaxTree(syntaxTree, newSyntaxTree);
diff --git a/src/UiPath.Workflow/Activities/VbExpressionValidator.cs b/src/UiPath.Workflow/Activities/VbExpressionValidator.cs
index a6e1b836..0017e887 100644
--- a/src/UiPath.Workflow/Activities/VbExpressionValidator.cs
+++ b/src/UiPath.Workflow/Activities/VbExpressionValidator.cs
@@ -95,8 +95,12 @@ protected override void UpdateCompilationUnit(ExpressionContainer expressionCont
         }
     }
 
-    protected override string CreateValidationCode(string types, string names, string code) =>
-        $"Public Shared Function CreateExpression() As Expression(Of Func(Of {types}))\nReturn Function({names}) ({code})\nEnd Function";
+    protected override string CreateValidationCode(string types, string names, ExpressionContainer expressionContainer)
+    {
+        var code = expressionContainer.ExpressionToValidate.Code;
+        return
+            $"Public Shared Function CreateExpression() As Expression(Of Func(Of {types}))\nReturn Function({names}) ({code})\nEnd Function";
+    }
 
     protected override SyntaxTree GetSyntaxTreeForExpression(ExpressionContainer expressionContainer) =>
         VisualBasicSyntaxTree.ParseText("? " + expressionContainer.ExpressionToValidate.Code, s_vbScriptParseOptions);