Font::getDetails() throws TypeError when Encoding is indirect reference to PDFObject

[kernie]

• PHP Version: 8.x (reproduced on 8.1–8.5)
• PDFParser Version: 2.12.4+

Description:

Font::getDetails() throws a TypeError when a font's /Encoding entry is stored as an indirect object reference (N 0 R) that resolves to a plain PDFObject — i.e. an encoding dictionary that lacks /Type /Encoding.

This is a valid PDF structure per PDF spec Table 5.11: an encoding dictionary may carry only a /Differences array and omit /Type and /BaseEncoding.

Header::resolveXRef() correctly resolves the reference to a PDFObject. However, Font::getDetails() then executes (string) $this->get('Encoding'), which fails because PDFObject has no __toString() method.

Error:

Object of class Smalot\PdfParser\PDFObject could not be converted to string
in Font.php:97

PDF input

Minimal reproducer (included in the fix PR under samples/bugs/EncodingAsIndirectPDFObject.pdf).

The relevant PDF structure:

4 0 obj
<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica /Encoding 5 0 R >>
endobj

5 0 obj
<< /Differences [32 /space 65 /A /B /C /D /E /F /G /H /I /J] >>
endobj

Expected output & actual output

Expected: Font::getDetails() returns ['Encoding' => 'Ansi', ...] (or the BaseEncoding name if present) without throwing.

Actual: TypeError: Object of class Smalot\PdfParser\PDFObject could not be converted to string

Code

$parser = new \Smalot\PdfParser\Parser();
$pdf    = $parser->parseFile('EncodingAsIndirectPDFObject.pdf');

foreach ($pdf->getPages() as $page) {
    foreach ($page->getFonts() as $font) {
        $font->getDetails(); // throws TypeError
    }
}