Bug#1077836: latexdiff: processing 13-page document takes indefinite time (11 hours so far)

[Manny]

Package: latexdiff
Version: 1.3.2-1
Severity: important
Tags: upstream
X-Debbugs-Cc: frederik.tilmann at gfz-potsdam.de, debbug.latexdiff at sideload.33mail.com

This was executed:

  $ latexdiff report_old.tex report_new.tex > report_diff.tex

After 11 hours the process is still running hard with CPU pegged
around 99% according to /top/. CPU fan is running which also indicates
hard work is being done. There is no output to indicate how much
progress has been made.

When compiled, the document yields 13 pages in PDF form. I do not
imagine that 11+ hours is reasonable for that volume. Bug fixes and
enhancements are needed.

 ① There is likely some kind of faulty logic such as an endless loop
 ② A progress indicator is needed
 ③ A detailed debug log is needed
 ④ Periodic assessments should be made throughout the processing as to
    whether reasonable progress is being made. If an hour is spent on a
    normal sized paragraph, the tool should abort and perhaps give an
    indication of which segment of text is exceeding time
    thresholds. This should be configurable but many users don’t know
    what to expect so there should be a reasonable default.

I’ve seen latexdiff take forever in past executions and had to give up
and kill it. The document latexdiff struggles with at the moment is a
bilingual document that uses parcolumns to produce a left and right
column.

-- System Information:
Debian Release: 12.5
  APT prefers stable-updates
  APT policy: (990, 'stable-updates'), (990, 'stable-security'), (990, 'stable'), (500, 'oldstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.10.0-28-amd64 (SMP w/2 CPU threads)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages latexdiff depends on:
ii  perl  5.36.0-7+deb12u1

Versions of packages latexdiff recommends:
ii  texlive-latex-base         2022.20230122-3
ii  texlive-latex-extra        2022.20230122-4
ii  texlive-latex-recommended  2022.20230122-3
ii  texlive-plain-generic      2022.20230122-4

Versions of packages latexdiff suggests:
ii  git  1:2.39.2-1.1

-- no debconf information