[Dependency] smalot/pdfparser: Font::getDetails() throws TypeError for PDFs with indirect /Encoding objects (upstream fix available in #822/#823)

Bug Report

Note: This is not a bug in LibreSign itself, but a heads-up about a bug in a vendored dependency that affects LibreSign users.

Summary

When uploading certain PDF files (e.g. PDFs with Type1 fonts where is an indirect object reference), LibreSign throws a fatal error:

This originates in the vendored library at:

Root Cause

The PDF spec (Table 5.11) allows a font's entry to be either a name or an indirect reference to an encoding dictionary (). When it is an indirect reference, tried to cast the to string via , which throws a in PHP 8+ because has no .

The affected PDF is not corrupt — it is valid per the PDF specification.

Upstream Fix

This has been reported and fixed upstream in :

• Issue: https://github.com/smalot/pdfparser/issues/822
• Pull Request (merged/open): https://github.com/smalot/pdfparser/pull/823

The fix adds a type-safe branch in that handles encoding dictionaries by reading the header entry instead of casting to string.

Request

Please update the vendored in to a version that includes the upstream fix (once merged), so that LibreSign users are no longer affected by this error.

Environment

• Nextcloud version: 33.0.5.1
• LibreSign vendored pdfparser commit:
• PHP version: 8.x
• Triggered by: Uploading a EncodingAsIndirectPDFObject.pdf PDF with Type1 fonts using indirect references

Nextcloud Log

Workaround

Until the vendored library is updated, the fix can be applied manually to:
3rdparty/composer/smalot/pdfparser/src/Smalot/PdfParser/Font.php

Replace the Encoding line in getDetails() with:

\$encoding = \$this->has('Encoding') ? \$this->get('Encoding') : null;
if (\$encoding instanceof PDFObject) {
    \$baseEncoding = \$encoding->getHeader()->get('BaseEncoding');
    \$details['Encoding'] = (\$baseEncoding instanceof Element && (string) \$baseEncoding !== '')
        ? (string) \$baseEncoding
        : 'Ansi';
} elseif (\$encoding instanceof Element) {
    \$details['Encoding'] = (string) \$encoding;
} else {
    \$details['Encoding'] = 'Ansi';
}

Start with 3rdparty/composer/smalot/pdfparser/src/Smalot/PdfParser/Font.php and check the vendored smalot/pdfparser version or commit. Compare it with upstream issue #822 and pull request #823, then verify the dependency update against the supplied EncodingAsIndirectPDFObject.pdf case. Done means the vendored version includes the upstream fix and the PDF upload no longer throws the PHP 8 TypeError.