[PORT]Refine template loop detection to enable recursive functions (#2305)

* Refine template loop detection to enable recursive functions

* Reduce the recursion stack depth to pass MacOS test

libraries/adaptive-expressions/src/memory/simpleObjectMemory.ts

@@ -16,7 +16,6 @@ import { ExpressionFunctions } from '../expressionFunctions';
 export class SimpleObjectMemory implements MemoryInterface {
 
     private memory: any = undefined;
-    private versionNumber: number = 0;
 
     public constructor(memory: any) {
         this.memory = memory;
@@ -142,13 +141,13 @@ export class SimpleObjectMemory implements MemoryInterface {
             }
         }
 
-        this.versionNumber++;
         return;
     }
 
     public  version(): string {
-        return this.versionNumber.toString();
+        return this.toString();
     }
+
     public toString(): string {
         return JSON.stringify(this.memory, this.getCircularReplacer());
     }

libraries/botbuilder-lg/src/customizedMemory.ts

@@ -57,6 +57,21 @@ export class CustomizedMemory implements MemoryInterface {
     }
 
     public  version(): string {
-        return '0';
+        let result = '';
+        if (this.globalMemory) {
+            const version = this.globalMemory.version();
+            if (version) {
+                result = result.concat(version);
+            }
+        }
+
+        if (this.localMemory) {
+            const localVersion = this.localMemory.version();
+            if (localVersion) {
+                result = result.concat(localVersion);
+            }
+        }
+
+        return result;
     }
 }

libraries/botbuilder-lg/src/evaluationTarget.ts

@@ -6,7 +6,7 @@
  * Copyright (c) Microsoft Corporation. All rights reserved.
  * Licensed under the MIT License.
  */
-import { CustomizedMemory } from './customizedMemory';
+import { MemoryInterface } from 'adaptive-expressions';
 
 
 /**
@@ -22,13 +22,13 @@ export class EvaluationTarget {
     /**
      * Scope.
      */
-    public scope: any;
+    public scope: MemoryInterface;
 
     /**
      * The children templates that this template has evaluated currently. 
      */
     public  evaluatedChildren: Map<string, any>;
-    public constructor(templateName: string, scope: any) {
+    public constructor(templateName: string, scope: MemoryInterface) {
         this.templateName = templateName;
         this.scope = scope;
         this.evaluatedChildren = new Map<string, any>();
@@ -40,24 +40,7 @@ export class EvaluationTarget {
      * @returns Id.
      */
     public getId(): string {
-        const memory = this.scope as CustomizedMemory;
-        let result = this.templateName;
-        if (memory) {
-            if (memory.globalMemory) {
-                const version = memory.globalMemory.version();
-                if (version) {
-                    result = result.concat(version);
-                }
-            }
-
-            if (memory.localMemory) {
-                const localMemoryString = memory.localMemory.toString();
-                if (localMemoryString) {
-                    result = result.concat(localMemoryString);
-                }
-            }
-        }
-
-        return result;
+        const scopeVersion = this.scope ? this.scope.version() : '';
+        return this.templateName + scopeVersion;
     }
 }

libraries/botbuilder-lg/src/evaluator.ts

@@ -73,6 +73,8 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGTempla
      * @returns Evaluate result.
      */
     public evaluateTemplate(inputTemplateName: string, scope: any): any {
+
+        const memory = scope instanceof CustomizedMemory ? scope : new CustomizedMemory(scope);
         let templateName: string;
         let reExecute: boolean;
         ({reExecute, pureTemplateName: templateName} = this.parseTemplateName(inputTemplateName));
@@ -81,19 +83,15 @@ export class Evaluator extends AbstractParseTreeVisitor<any> implements LGTempla
             throw new Error(TemplateErrors.templateNotExist(templateName));
         }
 
-        if (this.evaluationTargetStack.some((u: EvaluationTarget): boolean => u.templateName === templateName)) {
+        const templateTarget: EvaluationTarget = new EvaluationTarget(templateName, memory);
+        const currentEvulateId: string = templateTarget.getId();
+
+        if (this.evaluationTargetStack.some((u: EvaluationTarget): boolean => u.getId() === currentEvulateId)) {
             throw new Error(`${ TemplateErrors.loopDetected } ${ this.evaluationTargetStack.reverse()
                 .map((u: EvaluationTarget): string => u.templateName)
                 .join(' => ') }`);
         }
 
-        if (!(scope instanceof CustomizedMemory)) {
-            scope = new CustomizedMemory(SimpleObjectMemory.wrap(scope));
-        }
-
-        const templateTarget: EvaluationTarget = new EvaluationTarget(templateName, scope);
-        const currentEvulateId: string = templateTarget.getId();
-
         let previousEvaluateTarget: EvaluationTarget;
 
         if (this.evaluationTargetStack.length !== 0) {

libraries/botbuilder-lg/src/expander.ts

@@ -64,22 +64,22 @@ export class Expander extends AbstractParseTreeVisitor<string[]> implements LGTe
      * @returns All possiable results.
      */
     public expandTemplate(templateName: string, scope: any): any[] {
+        const memory = scope instanceof CustomizedMemory ? scope : new CustomizedMemory(scope);
         if (!(templateName in this.templateMap)) {
             throw new Error(TemplateErrors.templateNotExist(templateName));
         }
 
-        if (this.evaluationTargetStack.find((u: EvaluationTarget): boolean => u.templateName === templateName)) {
+        const templateTarget: EvaluationTarget = new EvaluationTarget(templateName, memory);
+        const currentEvulateId: string = templateTarget.getId();
+
+        if (this.evaluationTargetStack.find((u: EvaluationTarget): boolean => u.getId() === currentEvulateId)) {
             throw new Error(`${ TemplateErrors.loopDetected } ${ this.evaluationTargetStack.reverse()
                 .map((u: EvaluationTarget): string => u.templateName)
                 .join(' => ') }`);
         }
 
-        if (!(scope instanceof CustomizedMemory)) {
-            scope = new CustomizedMemory(SimpleObjectMemory.wrap(scope));
-        }
-        
         // Using a stack to track the evalution trace
-        this.evaluationTargetStack.push(new EvaluationTarget(templateName, scope));
+        this.evaluationTargetStack.push(templateTarget);
         const result: any[] = this.visit(this.templateMap[templateName].templateBodyParseTree);
         this.evaluationTargetStack.pop();
 

libraries/botbuilder-lg/tests/lg.test.js

@@ -645,6 +645,17 @@ describe('LG', function() {
         assert.strictEqual(evaled, 18, `Evaled is ${ evaled }`);
     });
 
+    it('TestRecursiveTemplate', function() {
+        var templates = Templates.parseFile(GetExampleFilePath('RecursiveTemplate.lg'));
+        var evaled = templates.evaluate('RecursiveAccumulate', {number: 10});
+        assert.strictEqual(evaled, 55);
+
+        var evaled = templates.evaluate('RecursiveFactorial', {number: 5});
+        assert.strictEqual(evaled, 1*2*3*4*5);
+
+        var evaled = templates.evaluate('RecursiveFibonacciSequence', {number: 5});
+        assert.strictEqual(evaled, 5);
+    });
 
     it('TestLGResource', function() {
         var templates = Templates.parseText(fs.readFileSync(GetExampleFilePath('2.lg'), 'utf-8'));

libraries/botbuilder-lg/tests/lgDiagnostic.test.js

@@ -214,6 +214,8 @@ describe(`LGExceptionTest`, function() {
         assert.throws(() => templates.evaluate(`wPhrase`), Error(`Loop detected: welcome_user => wPhrase [wPhrase]  Error occurred when evaluating '-\${wPhrase()}'. [welcome_user]  Error occurred when evaluating '-\${welcome_user()}'.`));
         
         assert.throws(() => templates.analyzeTemplate(`wPhrase`), Error('Loop detected: welcome_user => wPhrase'),);
+
+        assert.throws(() => templates.analyzeTemplate(`shouldFail`), Error('Loop detected: shouldFail'),);
     });
 
     it(`AddTextWithWrongId`, function() {

libraries/botbuilder-lg/tests/testData/examples/RecursiveTemplate.lg

@@ -0,0 +1,20 @@
+> 1 + 2 + 3 +...+ number
+# RecursiveAccumulate(number)
+- IF:${number <= 1}
+ - ${1}
+- ELSE:
+ - ${RecursiveAccumulate(number - 1) + number}
+
+> 1 * 2 * 3 * 4 * 5 * ... * number
+# RecursiveFactorial(number)
+- IF: ${number <= 1}
+ - ${1}
+- ELSE:
+ - ${RecursiveFactorial(number - 1) * number}
+
+> 1, 1, 2, 3, 5, 8, 13 ... number th
+# RecursiveFibonacciSequence(number)
+- IF: ${number <= 2}
+ - ${1}
+- ELSE:
+ - ${RecursiveFibonacciSequence(number - 1) + RecursiveFibonacciSequence(number - 2)}

libraries/botbuilder-lg/tests/testData/exceptionExamples/LoopDetected.lg

@@ -8,3 +8,6 @@
 # welcome_user
 - ${wPhrase()}
 
+> self loop
+# shouldFail(x)
+- ${shouldFail(x)}