"fitz.mupdf.FzErrorArgument: code=4: source object number out of range" after "add_redact_annot"

[bsdcpp]

Description of the bug

Hi, there.
Here's the situation: I'm trying to hide certain content in a PDF, so I used the following code. It seems like the code can only handle PDF files with one page, as it throws an error similar to the one mentioned above when dealing with more than one page.

from __future__ import print_function
import fitz, sys

src = fitz.open(sys.argv[1])
doc = fitz.open()

for spage in src:
    r = spage.rect
    redact_area = fitz.Rect(100, 100, 200, 200)
    spage.add_redact_annot(redact_area)
    spage.apply_redactions()  # clears areas to exclude

    page = doc.new_page(-1, width=r.width, height=r.height)
    page.show_pdf_page(
        page.rect,
        src,
        spage.number,
        clip=r,
    )

doc.save("output.pdf", garbage=4, deflate=True)

The code runs without errors if I comment out these two lines:

spage.add_redact_annot((0, 0, 100, 100))
spage.apply_redactions()  # clears areas to exclude

How to reproduce the bug

Any PDF file can be used to test the error code. I've tried several versions of PyMuPDF, and they all have this problem.
problem.pdf
No_problem.pdf

PyMuPDF version

1.24.2

Operating system

MacOS, Linux

Python version

3.11, 3.8

[JorjMcKie]

Applying redactions massively changes the structure of a PDF page.

As always in similar cases, this should be done outside a loop that iterates over the same objects. The following modified script works:

import fitz, sys

src = fitz.open(sys.argv[1])
doc = fitz.open()
for spage in src:
    redact_area = fitz.Rect(100, 100, 200, 200)
    spage.add_redact_annot(redact_area)
    spage.apply_redactions()  # clears areas to exclude

for spage in src:
    w, h = spage.rect.br
    page = doc.new_page(width=w, height=h)
    page.show_pdf_page(page.rect, src, spage.number, clip=spage.rect)

doc.ez_save(src.name.replace(".pdf", "-redacted.pdf"), garbage=4)

[JorjMcKie]

We will consider documenting an according caveat.

[bsdcpp]

Thanks a lot for your answer, amazing, it works.