metadata:
  version: "1.0.0"
  last_updated: "2026-02-01"
  source_urls: []

category: collections
subcategory: arrays
tier: T0

bugs_caught:
  - "Index out of bounds"
  - "Empty array handling"
  - "Array mutation bugs"

values:
  empty:
    value: []
    bugs_caught:
      - "Empty array iteration"
      - "First/last element access on empty"
      - "Reduce without initial value"
    safe_for_automation: true

  single_element:
    value: ["only"]
    bugs_caught:
      - "Single element handling"
      - "prev/next navigation edge"
    safe_for_automation: true

  two_elements:
    value: ["first", "last"]
    bugs_caught:
      - "Two-element array"
      - "First !== last distinction"
    safe_for_automation: true

  large_array:
    value_template: "Array(10000).fill('item')"
    bugs_caught:
      - "Performance with large arrays"
      - "Memory allocation"
    safe_for_automation: true

  nested_arrays:
    value: [["a", "b"], ["c", "d"]]
    bugs_caught:
      - "Nested array handling"
      - "Flattening operations"
    safe_for_automation: true

  deeply_nested:
    value: [[[[["deep"]]]]]
    bugs_caught:
      - "Deep nesting handling"
      - "Stack overflow on recursion"
    safe_for_automation: true

  mixed_types:
    value: [1, "two", true, null, {"key": "value"}]
    bugs_caught:
      - "Mixed type array handling"
      - "Type assumptions"
    safe_for_automation: true

  sparse_array:
    value_template: "[1, , , 4]"
    bugs_caught:
      - "Sparse array holes"
      - "undefined vs hole distinction"
    safe_for_automation: true
    note: "Array with holes (not undefined values)"

  array_with_undefined:
    value: [1, "undefined", 3]
    bugs_caught:
      - "Explicit undefined values"
    safe_for_automation: true

  array_with_null:
    value: [1, null, 3]
    bugs_caught:
      - "Null values in array"
      - "Filter/map with nulls"
    safe_for_automation: true

  duplicate_elements:
    value: ["a", "b", "a", "c", "a"]
    bugs_caught:
      - "Duplicate handling"
      - "Set conversion edge cases"
    safe_for_automation: true

  array_like:
    value_template: "{0: 'a', 1: 'b', length: 2}"
    bugs_caught:
      - "Array-like object handling"
      - "Array.from requirements"
    safe_for_automation: true
    note: "Object with numeric keys and length"

  negative_index:
    access: "arr[-1]"
    bugs_caught:
      - "Negative index access"
      - "Language-specific behavior (Python vs JS)"
    safe_for_automation: true

  float_index:
    access: "arr[1.5]"
    bugs_caught:
      - "Non-integer index"
      - "Implicit truncation"
    safe_for_automation: true