Arch Linux

Description:
Recent update from Ghostscript 9.26-2 to 9.27-1 breaks CUPS printing PDF documents with foomatic-rip (from cups-filters). Any attempt to print PDF document ends up with “Filter failure” message in CUPS web frontend job list. The same kind of error, although described in greater detail, is present in /var/log/cups/error_log, given the appropriate LogLevel is set. error_log shows that the source of the problem is a failure of Ghostscript which, in turn, leads foomatic-rip to fail to properly read number of pages in given PDF document (reported numer of pages is “-1”).

Further investigation leads to filter/foomatic-rip/pdf.c file in cups-filters source code. In this file, function pdf_count_pages invokes Ghostscript with a couple of PostScript commands to get number of pages in PDF file. This piece of code is actually quite helpful for testing purposes. It can be conveniently run directly from command line. For example, if sample PDF file is “sampl.pdf”, we can run:

gs -dNODISPLAY -q -c '/pdffile (sample.pdf) (r) file def pdfdict begin pdffile pdfopen begin (PageCount: ) print pdfpagecount == flush currentdict pdfclose end end quit'

The expected output should look (depending on actual number of pages) something like:

PageCount: 23

It is exactly so for Ghostscript 9.26-2, while for 9.27-1 the output is:

Error: /undefined in pdfdict
Operand stack:

Execution stack:
%interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval--
Dictionary stack:
--dict:731/1123(ro)(G)-- --dict:0/20(G)-- --dict:76/200(L)--
Current allocation mode is local
GPL Ghostscript 9.27: Unrecoverable error, exit code 1

This leads to pdf_count_pages to return -1 and effectively stop foomatic-rip altogether.

Both versions, however, are able to properly execute the following PostScript code, which gives exactly the same results:

gs -dNODISPLAY -q -c '/pdffile (sample.pdf) (r) file runpdfbegin (PageCount: ) print pdfpagecount = quit'

Unfortunately, I lack time to properly investigate what changes were done to Ghostscript since 9.26-2, so I can't be sure if, by a chance, the problem is caused by some planned deprecation. In that case the bug would be on foomatic-rip's side. It is certain, however, that some change in Ghostcript is responsible for the situation.

Additional info:
* Package version: 9.27-1

Steps to reproduce:

* Install newest Ghostscript 9.27-1, cups and cups-filters from repositories.
* Set up a printer.
* Attempt to print a PDF document