fix: nil pointer panic when framing an embedded @list value

The issue was identified where a nil pointer panic occurred during the
framing process when handling embedded @list values. This fix ensures
proper handling of such scenarios to prevent the application from
crashing unexpectedly.

Closes: #91
Co-authored-by: Alex Borodin <[email protected]>
Signed-off-by: Alex Borodin <[email protected]>
Signed-off-by: Michael Adler <[email protected]>

Author: michaeladler

ld/api_frame.go

@@ -617,21 +617,18 @@ func removeEmbed(state *FramingContext, id string) {
 func removeDependents(embeds map[string]*EmbedNode, id string) {
 	// get embed keys as a separate array to enable deleting keys in map
 	for idDep, e := range embeds {
-		var p map[string]interface{}
-		if e.parent != nil {
-			var isMap bool
-			p, isMap = e.parent.(map[string]interface{})
-			if !isMap {
-				continue
-			}
-		} else {
-			p = make(map[string]interface{})
+		if e.parent == nil {
+			continue
 		}
-
-		pid := p["@id"].(string)
-		if id == pid {
-			delete(embeds, idDep)
-			removeDependents(embeds, idDep)
+		p, isMap := e.parent.(map[string]interface{})
+		if !isMap {
+			continue
+		}
+		if pid, hasID := p["@id"]; hasID {
+			if id == pid.(string) {
+				delete(embeds, idDep)
+				removeDependents(embeds, idDep)
+			}
 		}
 	}
 }

ld/api_frame_test.go

@@ -15,10 +15,12 @@
 package ld_test
 
 import (
+	"encoding/json"
 	"testing"
 
 	. "github.com/piprate/json-gold/ld"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestGetFrameFlag(t *testing.T) {
@@ -76,3 +78,121 @@ func TestGetFrameFlag(t *testing.T) {
 	),
 	)
 }
+
+func TestJsonLdApi_Frame(t *testing.T) {
+	var input any
+	err := json.Unmarshal([]byte(shaclValidationResult), &input)
+	require.NoError(t, err)
+	var frame any
+	err = json.Unmarshal([]byte(shaclValidationResultFrame), &frame)
+	require.NoError(t, err)
+	framed, err := NewJsonLdProcessor().Frame(input, frame, nil)
+	require.NoError(t, err)
+	assert.Equal(t, []any{map[string]any{
+		"sh:resultPath": "https://example.com/hasScrewable",
+		"sh:sourceShape": map[string]any{
+			"sh:or": map[string]any{
+				"@list": []any{
+					map[string]any{
+						"sh:class": "https://example.com/Bolt",
+						"type":     "sh:NodeShape",
+					},
+					map[string]any{
+						"sh:class": "https://example.com/Screw",
+						"type":     "sh:NodeShape",
+					},
+				},
+			},
+			"sh:path": "https://example.com/hasScrewable",
+			"type":    "sh:PropertyShape",
+		},
+		"type": "sh:ValidationResult",
+	}}, framed["@graph"])
+}
+
+const shaclValidationResult = `
+[
+  {
+    "@id": "_:ccbca2cd103643858f1087647dd5399717617",
+    "@type": [
+      "http://www.w3.org/ns/shacl#ValidationResult"
+    ],
+    "http://www.w3.org/ns/shacl#resultPath": [
+      {
+        "@id": "https://example.com/hasScrewable"
+      }
+    ],
+    "http://www.w3.org/ns/shacl#sourceShape": [
+      {
+        "@id": "_:node94090"
+      }
+    ]
+  },
+  {
+    "@id": "_:node94090",
+    "@type": [
+      "http://www.w3.org/ns/shacl#PropertyShape"
+    ],
+    "http://www.w3.org/ns/shacl#or": [
+      {
+        "@list": [
+          {
+            "@id": "_:node94092"
+          },
+          {
+            "@id": "_:node94094"
+          }
+        ]
+      }
+    ],
+    "http://www.w3.org/ns/shacl#path": [
+      {
+        "@id": "https://example.com/hasScrewable"
+      }
+    ]
+  },
+  {
+    "@id": "_:node94092",
+    "@type": [
+      "http://www.w3.org/ns/shacl#NodeShape"
+    ],
+    "http://www.w3.org/ns/shacl#class": [
+      {
+        "@id": "https://example.com/Bolt"
+      }
+    ]
+  },
+  {
+    "@id": "_:node94094",
+    "@type": [
+      "http://www.w3.org/ns/shacl#NodeShape"
+    ],
+    "http://www.w3.org/ns/shacl#class": [
+      {
+        "@id": "https://example.com/Screw"
+      }
+    ]
+  }
+]`
+
+const shaclValidationResultFrame = `{
+  "@context": {
+    "sh": "http://www.w3.org/ns/shacl#",
+    "sh:resultPath": {
+      "@id": "sh:resultPath",
+      "@type": "@id"
+    },
+    "sh:path": {
+      "@id": "sh:path",
+      "@type": "@id"
+    },
+    "sh:class": {
+      "@id": "sh:class",
+      "@type": "@id"
+    },
+    "type": "@type",
+    "value": "@value",
+    "id": "@id"
+  },
+  "@type": "sh:ValidationResult"
+}`