scrub: fix edge case with nested objects in arrays

In certain conditions the scrubbing would end up getting
out of sync with its position in the stream.

Thanks Dan Upton for reporting.

pkg/scrub/scrub.go

@@ -132,19 +132,26 @@ func (s *stream) processValue(nodes []node) {
 }
 
 func (s *stream) processArray(nodes []node) {
+	s.next() // Move to first array value
 	for {
-		s.next()
-		if s.tok == unknown || s.tok == arrayEnd {
+		if s.tok == unknown {
+			return
+		} else if s.tok == arrayEnd {
+			s.next()
 			return
 		}
+
 		s.processValue(nodes)
 	}
 }
 
 func (s *stream) processObject(nodes []node) {
 	s.next() // Move to the first key
 	for {
-		if s.tok == unknown || s.tok == objectEnd {
+		if s.tok == unknown {
+			return
+		} else if s.tok == objectEnd {
+			s.next()
 			return
 		}
 

pkg/scrub/scrub_test.go

@@ -240,6 +240,18 @@ func TestJSON(t *testing.T) {
 			},
 			wantOutput: `{"One":["\"one\""]}}`,
 		},
+		{
+			name:  "multiple_array_nested_obj",
+			input: `{"one": [{"two": {"three": "ABC"}}, {"two": {"three": "DEF"}}]}`,
+			paths: []Path{
+				[]PathEntry{
+					{Kind: ObjectField, FieldName: `"one"`, CaseSensitive: true},
+					{Kind: ObjectField, FieldName: `"two"`, CaseSensitive: true},
+					{Kind: ObjectField, FieldName: `"three"`, CaseSensitive: true},
+				},
+			},
+			wantOutput: `{"one": [{"two": {"three": "[sensitive]"}}, {"two": {"three": "[sensitive]"}}]}`,
+		},
 	}
 
 	for _, tt := range tests {