Seems reasonable.

I would add a _bool_eval check in _fill_gallery_conf_defaults for the new config.

I think we could add a test in test_gen_gallery.py, using @pytest.mark.add_conf to set the config. Note that the tests here use sphinx_app_wrapper which builds the docs in sphinx_gallery/tests/testconfs/src

done

Another note to myself - I should improve the documentation. I did not realise text block links are added by sphinx and are thus dictated by sphinx intersphinx config. We only add the code block links and by default will add for all modules in intersphinx, but check modules in reference_url first. We need to add local module to reference_url, to add links to local module in code.

I think I need help to write a test

From #1409 (comment) also instead of a pure boolean I wonder if we should let this be a regex string with default .* for things to link. If you set it to an empty string it links nothing. For @drammock's use case it might be r"mne\..*" for example to link only to MNE objects or whatever

I think I need help to write a test

I had a quick play and something like this should work:

@pytest.mark.add_conf(
    content=r"""
import sys

intersphinx_mapping = {
    "python": (f"https://docs.python.org/{sys.version_info.major}", None),
}
sphinx_gallery_conf = {
    'examples_dirs': 'src',
    'gallery_dirs': 'ex',
    'embed_code_links': True,
}"""
)
def test_embed_code_links(sphinx_app_wrapper):
    """Check `embed_code_links` works."""
    sphinx_app = sphinx_app_wrapper.build_sphinx_app()
    built_example = Path(sphinx_app.outdir, "ex", "plot_1.html")

    with open(built_example, "r", encoding="utf-8") as fid:
        html = fid.read()
    print(html) # Check link has/has not been added in html

I thought that since I added python to intersphinx, print function in example plot_1.py would be linked but it wasn't? Looking at the SG docs themselves, print calls in our examples are also not linked, but variables that are built-ins e.g., string or list are. Maybe I've mis-understood something though?

thanks @lucyleeow I added all in one commit

@jschueller sorry not sure what you added? AFAICT the test still is just a print ?

Also I think @larsoner 's suggestion of having the config be more flexible with a regex would be nice:
#1410 (comment)