fixes https://github.com/zazuko/rdf-validate-shacl/issues/136

.changeset/many-queens-matter.md

@@ -0,0 +1,5 @@
+---
+"rdf-validate-shacl": patch
+---
+
+Added a `maxNodeChecks` option to prevent `too much recursion` error caused by cyclic shape references (fixes #136)

src/validation-engine.js

@@ -4,12 +4,14 @@ import ValidationReport from './validation-report.js'
 import { extractStructure, extractSourceShapeStructure } from './dataset-utils.js'
 
 const error = debug('validation-enging::error')
+const defaultMaxNodeChecks = 50
 
 class ValidationEngine {
   constructor(context, options) {
     this.context = context
     this.factory = context.factory
     this.maxErrors = options.maxErrors
+    this.maxNodeChecks = options.maxNodeChecks === undefined ? defaultMaxNodeChecks : options.maxNodeChecks
     this.initReport()
     this.recordErrorsLevel = 0
     this.violationsCount = 0
@@ -18,11 +20,12 @@ class ValidationEngine {
   }
 
   clone() {
-    return new ValidationEngine(this.context, { maxErrors: this.maxErrors })
+    return new ValidationEngine(this.context, { maxErrors: this.maxErrors, maxNodeChecks: this.maxNodeChecks })
   }
 
   initReport() {
     const { rdf, sh } = this.context.ns
+    this.nodeCheckCounters = {}
 
     this.reportPointer = clownface({
       dataset: this.factory.dataset(),
@@ -67,6 +70,18 @@ class ValidationEngine {
 
     if (shape.deactivated) return false
 
+    if (this.maxNodeChecks > 0) {
+      // check how many times we have already tested this focusNode against this shape
+      const id = JSON.stringify([focusNode, shape.shapeNode])
+      const nodeCheckCounter = this.nodeCheckCounters[id] === undefined ? 0 : this.nodeCheckCounters[id]
+      if (nodeCheckCounter > this.maxNodeChecks) {
+        // max node checks reached, so bail out
+        return false
+      }
+      // increment check counter for given focusNode/shape pair
+      this.nodeCheckCounters[id] = nodeCheckCounter + 1
+    }
+
     const valueNodes = shape.getValueNodes(focusNode, dataGraph)
     let errorFound = false
     for (const constraint of shape.constraints) {

test/data/data-shapes/custom/circularReferences.ttl

@@ -0,0 +1,48 @@
+@prefix dash: <http://datashapes.org/dash#> .
+@prefix ex: <http://example.org#> .
+@prefix mf: <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix sh: <http://www.w3.org/ns/shacl#> .
+@prefix sht: <http://www.w3.org/ns/shacl-test#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+<>
+  rdf:type mf:Manifest ;
+  mf:entries (
+      <circularReferences>
+    ) ;
+.
+
+<circularReferences>
+  rdf:type sht:Validate ;
+  rdfs:label "Test of circular references in data graph" ;
+  mf:action [
+      sht:dataGraph <> ;
+      sht:shapesGraph <> ;
+    ] ;
+  mf:result [
+      rdf:type sh:ValidationReport ;
+      sh:conforms "true"^^xsd:boolean ;
+  ] ;
+.
+
+ex:Thing
+    a sh:NodeShape,rdfs:Class ;
+    sh:property [
+                  sh:path         ex:references ;
+                  sh:node         ex:Thing
+                ] ;
+    sh:targetClass <Thing>
+.
+
+<thing1>
+    a <Thing> ;
+    ex:references <thing2>
+.
+
+<thing2>
+    a <Thing> ;
+    ex:references <thing1> ;
+.

test/data/data-shapes/custom/manifest.ttl

@@ -11,4 +11,5 @@
 	mf:include <multiLevelInheritanceWithImplicitTarget.ttl> ;
 	mf:include <targetNodeDoesNotExist.ttl> ;
 	mf:include <lessThan-moreTypes.ttl> ;
+	mf:include <circularReferences.ttl> ;
 	.