Add ThrowOnRecursive to AnalyzerOptions

libraries/Microsoft.Bot.Builder.LanguageGeneration/Analyzer.cs

@@ -50,7 +50,23 @@ public Analyzer(Templates templates, EvaluationOptions opt = null)
         /// <returns>Analyze result including variables and template references.</returns>
         public AnalyzerResult AnalyzeTemplate(string templateName)
         {
-            if (!_templateMap.ContainsKey(templateName) || _evaluationTargetStack.Any(e => e.TemplateName == templateName))
+            var missingName = !_templateMap.ContainsKey(templateName);
+            var stackHasName = _evaluationTargetStack.Any(e => e.TemplateName == templateName);
+
+            if (Templates.LgOptions?.ThrowOnRecursive == true)
+            {
+                if (missingName)
+                {
+                    throw new ArgumentException(TemplateErrors.TemplateNotExist(templateName));
+                }
+
+                if (stackHasName)
+                {
+                    throw new InvalidOperationException($"{TemplateErrors.LoopDetected} {string.Join(" => ", _evaluationTargetStack.Reverse().Select(e => e.TemplateName))} => {templateName}");
+                }
+            }
+
+            if (missingName || stackHasName)
             {
                 return new AnalyzerResult();
             }
@@ -210,7 +226,7 @@ private AnalyzerResult AnalyzeExpressionDirectly(Expression exp)
                 }
                 else
                 {
-                    if (!result.TemplateReferences.Contains(templateName))
+                    if (Templates.LgOptions?.ThrowOnRecursive == true || !result.TemplateReferences.Contains(templateName))
                     {
                         // if template has parameters, just get the template ref without variables.
                         result.Union(new AnalyzerResult(templateReferences: this.AnalyzeTemplate(templateName).TemplateReferences));

libraries/Microsoft.Bot.Builder.LanguageGeneration/EvaluationOptions.cs

@@ -55,6 +55,7 @@ public class EvaluationOptions
         private readonly string _replaceNullKey = "@replaceNull";
         private readonly string _lineBreakKey = "@lineBreakStyle";
         private readonly string _cacheScope = "@cacheScope";
+        private readonly string _throwOnRecursive = "@throwOnRecursive";
 
         /// <summary>
         /// Initializes a new instance of the <see cref="EvaluationOptions"/> class.
@@ -67,6 +68,7 @@ public EvaluationOptions()
             Locale = null;
             OnEvent = null;
             CacheScope = null;
+            ThrowOnRecursive = null;
         }
 
         /// <summary>
@@ -81,6 +83,7 @@ public EvaluationOptions(EvaluationOptions opt)
             Locale = opt.Locale ?? Thread.CurrentThread.CurrentCulture.Name;
             OnEvent = opt.OnEvent;
             CacheScope = opt.CacheScope;
+            ThrowOnRecursive = opt.ThrowOnRecursive;
         }
 
         /// <summary>
@@ -124,6 +127,13 @@ public EvaluationOptions(IList<string> optionsList)
                                 }
                             }
                         }
+                        else if (key.Equals(_throwOnRecursive, StringComparison.OrdinalIgnoreCase))
+                        {
+                            if (value.ToLowerInvariant() == "true")
+                            {
+                                ThrowOnRecursive = true;
+                            }
+                        }
                     }
                 }
             }
@@ -178,6 +188,14 @@ public EvaluationOptions(IList<string> optionsList)
         /// </value>
         public LGCacheScope? CacheScope { get; set; } = null;
 
+        /// <summary>
+        /// Gets or sets a value determining if recursive calls throw an exception.
+        /// </summary>
+        /// <value>
+        /// When true, throw an exception if a recursive call is detected.
+        /// </value>
+        public bool? ThrowOnRecursive { get; set; } = null;
+
         /// <summary>
         /// Merge a incoming option to current option. If a property in incoming option is not null while it is null in current
         /// option, then the value of this property will be overwritten.

libraries/Microsoft.Bot.Builder.LanguageGeneration/Templates.cs

@@ -324,7 +324,7 @@ public IList<object> ExpandTemplate(string templateName, object scope = null, Ev
         public AnalyzerResult AnalyzeTemplate(string templateName)
         {
             CheckErrors();
-            var analyzer = new Analyzer(this);
+            var analyzer = new Analyzer(this, this.LgOptions);
             return analyzer.AnalyzeTemplate(templateName);
         }
 

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplateDiagnosticTest.cs

@@ -289,6 +289,14 @@ public void TestLoopDetected()
             var lgFile = GetTemplates("LoopDetected.lg");
             var exception = Assert.Throws<InvalidOperationException>(() => lgFile.Evaluate("wPhrase"));
             Assert.Contains(TemplateErrors.LoopDetected, exception.Message);
+
+            lgFile.Options = new List<string> { "@throwOnRecursive=true" };
+
+            exception = Assert.Throws<InvalidOperationException>(() => lgFile.AnalyzeTemplate("wPhrase"));
+            Assert.Contains(TemplateErrors.LoopDetected, exception.Message);
+
+            exception = Assert.Throws<InvalidOperationException>(() => lgFile.AnalyzeTemplate("shouldFail"));
+            Assert.Contains(TemplateErrors.LoopDetected, exception.Message);
         }
 
         [Fact]