orgmode latex export: How to create repeatable labels?

Question

Every time I export org-mode document to LaTeX, most sections get new and unique labels, e.g.,

\section{Introduction}
\label{sec:orge0665da}

The next time I export the document, the label will change, e.g.,

 \section{Introduction}
 \label{sec:orgcd0c5bf}

If I want to do a diff of the LaTeX documents to a previous version, I get a ton of changed labels that hide the changes I have made to the text. Sometimes this confuses latexdiff as well.

Is there a way to ensure that the exported labels are the same between exports? At least for as long as the number of (sub)sections does not change? Set a seed to a random number generator? Write a hook function that returns a label given a section?

I am aware of Is there a way to suggest label names in org-mode latex export?, that solves the problem for a specific label, but not the (in org-mode) un-labelled sections.

Answer 1

I think you hit on the solution yourself:

Set a seed to a random number generator?

That seems to work just fine in my limited testing. The function org-export-new-reference in ox.el does indeed call random to generate the reference label.

To seed the random number generator, call random with some string (it seeds the generator with some value computed from the string). If you want the generator seeded before every single export use the org-export-before-processing-hook:

(defun seed-random-generator (_) (random "a fixed and unchanging string"))
(add-hook 'org-export-before-processing-hook #'seed-random-generator)

(To be honest, I don't really understand why you'd want to diff the generated LaTeX files instead of diffing the original org files. At least you're not diffing PDFs. :P)