Rebuild only the necessary ReST files.

[xmo-odoo]

Currently sphinx_js basically rebuilds the documentation every time as it hooks on env-before-read-docs and expands docs to process to all found_docs[0]. The docstring of the callback specifically notes that this is done "because we have no way of telling which ones reference JS code that might have changed".

Turns out, as I somehow managed to find out for an other project Sphinx actually has the tools for that: BuildEnvironment.note_dependency.

Just invoke it with the relevant source file(s) during directive processing and it will add the source file as a dependency of the current rST document, and will remember that during the next (incremental) build.

[0] incidentally a simpler version might have been to hook onto env-get-outdated and return found_docs, anything returned by the env-get-outdated handler is considered a changed file.

[erikrose]

Good find! I think that should be pretty easy to do. We'd just have to tread carefully when doing something like autoclass, which can pull things in from multiple files when documenting its members, via JSDoc tags like @lends.