XINCGer/Unity3DTraining · error · ArgumentException

Not enough space in the array

Error message

Not enough space in the array

What it means

MapView.CopyTo throws ArgumentException when the target array cannot hold all elements from the given start index: the check arrayIndex + Count >= array.Length rejects cases with insufficient (or exactly tight) space.

Solutions

1. Size the array as arrayIndex + Count (plus slack) before CopyTo
2. Use ToArray()/ToList() on the view instead of manual CopyTo
3. Re-check mapField.Count at copy time; the map may have changed since the buffer was sized
4. Account for the >= (not >) check: allocate strictly more than index+Count

Example fix

// before
var arr = new byte[mapField.Count];
mapField.Values.CopyTo(arr, 0); // may throw if count changed
// after
var arr = new T[mapField.Count + 1];
mapField.Values.CopyTo(arr, 0);

if (arr.Length - arrayIndex <= view.Count) arr = new T[arrayIndex + view.Count + 1];

try { view.CopyTo(arr, idx); } catch (ArgumentException) { arr = new T[view.Count + idx + 1]; view.CopyTo(arr, idx); }

When it happens

Trigger: mapField.Keys.CopyTo(smallArray, idx) where idx + Count >= smallArray.Length, e.g. copying a 10-element Values view into an 8-element array or an exact-fit array at a nonzero offset.

Common situations: Reusing stale buffers after the map grew; assuming Keys/Values counts match a previously sized array; off-by-one sizing that the >= check rejects even for exact fits.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• " " is not a valid identifier.
• Dictionary has entry with null key
• Enums must contain at least one value.
• Field number has already been used in " " by field " ".
• Field numbers must be positive integers.

AI-assisted analysis of XINCGer/Unity3DTraining@016f98412e (2026-09-12). Data as JSON: /api/errors/7fbf1dcd0a5eb9c4. Report an issue: GitHub.

Appendix: source

Thrown at NetWorkAndResources/Socket_Protobuff/Assets/Plugins/Google.Protobuf/Collections/MapField.cs:720

            public void Clear()
            {
                throw new NotSupportedException();
            }

            public bool Contains(T item)
            {
                return containsCheck(item);
            }

            public void CopyTo(T[] array, int arrayIndex)
            {
                if (arrayIndex < 0)
                {
                    throw new ArgumentOutOfRangeException("arrayIndex");
                }
                if (arrayIndex + Count >= array.Length)
                {
                    throw new ArgumentException("Not enough space in the array", "array");
                }
                foreach (var item in this)
                {
                    array[arrayIndex++] = item;
                }
            }

            public IEnumerator<T> GetEnumerator()
            {
                return parent.list.Select(projection).GetEnumerator();
            }

            public bool Remove(T item)
            {
                throw new NotSupportedException();
            }

            IEnumerator IEnumerable.GetEnumerator()

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