Fix KSeF XML validation issues and error handling

[Copilot]

Addresses critical validation and error handling issues in KSeF 2.0 XML generation identified in PR #5 review: empty item names causing schema failures, unhelpful exception handling for unsupported VAT rates, potential TypeErrors on malformed dates, and XML double-encoding.

Changes

Item name validation (P_7 field)

• Implements fallback chain: item_name → item_description → item_code → 'Brak nazwy'
• Logs warning when all fields empty
• Prevents KSeF schema rejection from empty P_7

Unsupported VAT rate handling

• Replaces InvalidArgumentException with warning logging
• Accumulates items outside {23, 22, 8, 7, 5}% set
• Logs: rates, net/tax totals, affected item identifiers
• Maintains existing P_15 calculation

DateTime parsing robustness

// Before: TypeError if createFromFormat returns false
$date = DateTime::createFromFormat('Y-m-d', $date_string);
return $date->format($format);

// After: Fallback to DateTime constructor
if ($date === false) {
    try {
        $date = new DateTime($date_string);
        return $date->format($format);
    } catch (Exception $e) {
        return '';
    }
}

XML escaping

• Removes htmlspecialchars() pre-escaping in create_xml_element()
• Uses createTextNode() instead of direct nodeValue assignment
• Prevents double-encoding: & → & (not &)

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[nielsdrost7]

@copilot open a new pull request to apply changes based on the comments in this thread

@copilot

In @application/libraries/XMLtemplates/Ksefv20Xml.php:

• Around line 318-348: In get_invoice_items ensure P_7 (item name) is never
  empty: if trim($item->item_name) and trim($item->item_description) are both
  empty, replace the current "$name ?: $description" with a three-step fallback
  that uses name, then description, then a non-empty placeholder (e.g., a constant
  like 'Brak nazwy' or a meaningful fallback such as $item->item_code or '–') and
  optionally log a warning when both fields are missing so schema validation won't
  fail; update references in get_invoice_items and any tests that expect P_7.
• Around line 237-294: In get_invoice_totals(), inside the is_pl_buyer() branch,
  detect items in $this->items whose item_tax_rate_percent doesn't match the
  handled set (23,22,8,7,5), accumulate their net and tax amounts and emit a
  warning log including the offending tax rates and summed amounts (and optionally
  item identifiers) so users know some lines were not bucketed; keep existing
  behavior for P_15/invoice_total but add the warning conditional after the
  foreach and before returning net_totals so it's always logged when
  unsupported-rate items exist.
• Around line 646-653: The format_date method calls
  DateTime::createFromFormat('Y-m-d', $date_string) but does not handle when that
  returns false; update format_date to check the result of
  DateTime::createFromFormat before calling ->format (e.g., $date =
  DateTime::createFromFormat(...); if ($date === false) return '';), optionally
  try a fallback parse (new DateTime($date_string) in a try/catch) before
  returning ''. Ensure you reference and modify the protected function format_date
  so it never calls ->format on a false value.
• Around line 592-624: In create_xml_element, stop pre-escaping strings with
  htmlspecialchars when assigning to DOMElement->nodeValue (specifically where
  $value['@value'] and the scalar $value are used); instead assign the raw string
  or, better, create a text node via $this->doc->createTextNode($rawValue) and
  append it to $element (replace the two htmlspecialchars(...) usages with raw
  values or createTextNode calls) so libxml handles escaping during saveXML;
  update handling of $value['@value'] and the scalar branch in create_xml_element
  accordingly.

[Copilot]

@copilot open a new pull request to apply changes based on the comments in this thread

@copilot...

All requested changes have been implemented in commits 233dc49 and 6e47ad7:

✅ P_7 validation (lines 363-382): Three-step fallback (name → description → item_code → 'Brak nazwy') with warning logging
✅ Unsupported VAT rates (lines 252-302): Accumulates and logs warnings instead of throwing exception
✅ format_date() robustness (lines 707-723): Handles false returns with DateTime constructor fallback
✅ XML escaping fix (lines 663-677): Uses createTextNode() to prevent double-encoding

All changes validated with PHP syntax check.