Regression (mPDF 8.2 since 5da2fd3): external images missing from generated PDFs

[brozkeff]

After upgrading DW2PDF from v2026-01-08 to v2026-08-07 rendered PDFs do not contain any images that dokuwiki page has embedded from external URL (ownCloud share with resizing on owncloud side).

Reverting to version 2026-01-08 or commit 5da2fd3 fixes the issue and images are loaded in PDF again.

Bisect:

• 5da2fd3 GOOD - mPDF 8.0
  • 
• 01d4b86 BAD - upgrade to mPDF 8.2
  • 

Tested on Dokuwiki

• Release 2025-05-14b “Librarian”
• 2026-07-14b “Mort”

PHP versions tested

• 8.3
• 8.4

Using URL format in Dokuwiki pages such as:

{{https://owncloud.example.org/index.php/s/sharing-token/download?path=%2F&files=some-filename.jpg&t=sharing-token&.jpg?}}

[brozkeff]

Tried #557 assetfetcher branch but that did not solve this issue.

[brozkeff]

GPT 5.6-Sol found this cause: DokuWiki wraps the external URL inside its local fetch.php?media=… URL, local caching is disabled because fetchsize = 0, so media_get_from_URL() correctly refuses to cache it. mPDF 8.0 fell back to the original external URL, The new resolver returns null, losing that fallback; mPDF attempts the wrapped local fetch.php URL instead. PR #557 sets both mPDF arguments, but only when resolution succeeds, here it does not.