[Solved] can't install it on the heroku-20 stack

[did]

It complains about not finding the Python config tool while building the gobject-introspection lib.
...

Fortunately, I've found a much easier solution to get poppler working in my rails app:

1/ I added the apt buildpack (https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku-community/apt.tgz) to my Heroku app (must be in first position).

2/ My Aptfile file (stored at the root of my app) contains the following content:

gir1.2-poppler-0.18
libpoppler-dev
libpoppler-glib-dev
poppler-utils

[MattFenelon]

Great!

[MattFenelon]

You should be able to use Heroku's official apt buildpack https://github.com/heroku/heroku-buildpack-apt.