cayleygraph/cayley · error

No matching values for the item %#v in %#v

Error message

No matching values for the item %#v in %#v

What it means

In linkedql's JSON-LD pattern comparison (jsonld_util.go:61), the isomorphic function recursively compares a source JSON-LD value against a target value. When the source is a slice (ldSlice), every element of the target slice is checked for a structurally isomorphic match; if any source element has no match, this error is thrown. It means the pattern's array value does not correspond element-wise/structurally to the expected JSON-LD data.

Source

Thrown at query/linkedql/steps/jsonld_util.go:61

			return fmt.Errorf("Expected \"%v\" but instead received \"%v\"", s, t)
		}
		return nil
	case ldArray:
		t, ok := target.(ldArray)
		if !ok {
			return fmt.Errorf("Expected multiple values but instead received the single value: %#v", target)
		}
		if len(s) != len(t) {
			return fmt.Errorf("Expected %#v and %#v to have the same length", s, t)
		}
	items:
		for _, i := range s {
			for _, tI := range t {
				if isomorphic(i, tI) == nil {
					continue items
				}
			}
			return fmt.Errorf("No matching values for the item %#v in %#v", i, t)
		}
		return nil
	case ldMap:
		t, ok := target.(ldMap)
		if !ok {
			return fmt.Errorf("Expected %#v to be a map or a slice with a single map but instead received %T", target, target)
		}
		for k, v := range s {
			tV, _ := t[k]
			err := isomorphic(v, tV)
			if err != nil {
				return err
			}
		}
	}
	return nil
}

View on GitHub (pinned to 81dcd7d73e)

Solutions

1. Check each element of the source array against the target data for exact structural equality (properties, @id, @type).
2. Fix typos in IRIs, @type names, or keys inside the array value of the pattern.
3. If the element is legitimately optional, remove it from the pattern array or restructure the pattern.
4. Log both %#v values from the error message to identify which element failed to match.

Example fix

// before
pattern := map[string]interface{}{"@type": []interface{}{"Preson"}} // typo
// after
pattern := map[string]interface{}{"@type": []interface{}{"Person"}}

func arrayElementsPresentIn(pattern []interface{}, target []interface{}) bool {
  for _, p := range pattern {
    found := false
    for _, t := range target {
      if reflect.DeepEqual(p, t) { found = true; break }
    }
    if !found { return false }
  }
  return true
}

func asLDMapSlice(v interface{}) ([]map[string]interface{}, bool) {
  s, ok := v.([]interface{})
  if !ok { return nil, false }
  out := make([]map[string]interface{}, 0, len(s))
  for _, e := range s {
    m, ok := e.(map[string]interface{})
    if !ok { return nil, false }
    out = append(out, m)
  }
  return out, true
}

if err := isomorphic(src, target); err != nil {
  // err names the non-matching item in %#v; log and fall back to looser matching
  log.Printf("pattern mismatch: %v", err)
}

When it happens

Trigger: Calling isomorphic (directly or via pattern parsing) with a source ldSlice whose element has no isomorphic counterpart in the target ldSlice, e.g. a pattern like {"@type": ["Person"]} compared against data lacking a matching entry.

Common situations: Writing LinkedQL JSON-LD patterns where an array of values (types, IRIs, nested objects) does not match any element in the document being matched; typos in IRIs or type names inside arrays.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Expected %#v to be a map or a slice with a single map but in
• Unexpected type for @id %T
• Pattern does not parse to any quad. `{}` is the only pattern
• must execute a IteratorStep or PathStep
• Not implemented: should tag all properties

AI-assisted analysis of cayleygraph/cayley@81dcd7d73e (2026-09-06). Data as JSON: /api/errors/c226aedcd0759c74. Report an issue: GitHub.