Description of the bug
PyMuPDF raises pymupdf.mupdf.FzErrorFormat: code=7: cycle in resources when it loads or processes a page containing a Widget annotation whose /Parent entry points to itself. The malformed form-field relationship makes the complete page unusable, including operations unrelated to forms.
This seems to be distinct from #4986: the page tree is valid here. The cycle is contained in the annotation/form field graph.
Concretely, for the attached reproducer:
- Page 0 lives at xref 4 and correctly declares
/Parent 2 0 R, a /Pages node.
- Page 0 declares
/Annots [7 0 R 8 0 R].
- Widget 7 declares
/Parent 7 0 R, i.e. itself.
7 0 obj
<<
/Type /Annot
/Subtype /Widget
/P 4 0 R
/Parent 7 0 R
...
>>
endobj
The error fires immediately when the page is loaded.
Besides, it also occurs through Document._do_links(): insert_pdf(..., annots=False, widgets=False, links=False) can rebuild the page, but links=True fails even with annots=False and widgets=False.
The source has no actual links. The link-copy pass still loads every source page to ask for its links, which triggers the cyclic Widget-parent traversal.
How to reproduce the bug
import pymupdf
source = pymupdf.open("repro_widget_parent_cycle.pdf")
print(f"Pages: {source.page_count}")
source.load_page(0) # raises FzErrorFormat: code=7: cycle in resourcesThe same failure occurs during link copying:
destination = pymupdf.open()
destination.insert_pdf(
source,
annots=False,
widgets=False,
links=True,
)
# raises FzErrorFormat: code=7: cycle in resourcesrepro_widget_parent_cycle.pdf is a synthetic, one-page reproducer derived from the original PDF.
PyMuPDF version
1.28.2
Operating system
Linux
Python version
3.13
Description of the bug
PyMuPDF raises
pymupdf.mupdf.FzErrorFormat: code=7: cycle in resourceswhen it loads or processes a page containing a Widget annotation whose/Parententry points to itself. The malformed form-field relationship makes the complete page unusable, including operations unrelated to forms.This seems to be distinct from #4986: the page tree is valid here. The cycle is contained in the annotation/form field graph.
Concretely, for the attached reproducer:
/Parent 2 0 R, a/Pagesnode./Annots [7 0 R 8 0 R]./Parent 7 0 R, i.e. itself.The error fires immediately when the page is loaded.
Besides, it also occurs through
Document._do_links():insert_pdf(..., annots=False, widgets=False, links=False)can rebuild the page, butlinks=Truefails even withannots=Falseandwidgets=False.The source has no actual links. The link-copy pass still loads every source page to ask for its links, which triggers the cyclic Widget-parent traversal.
How to reproduce the bug
The same failure occurs during link copying:
repro_widget_parent_cycle.pdf is a synthetic, one-page reproducer derived from the original PDF.
PyMuPDF version
1.28.2
Operating system
Linux
Python version
3.13