LSIF is a file format for precomputed code intelligence data. It provides fast and precise code intelligence, but needs to be periodically generated and uploaded to your Sourcegraph instance. LSIF is opt-in: repositories for which you have not uploaded LSIF data will continue to use the out-of-the-box code intelligence.
LSIF is supported in Sourcegraph 3.8 and up.
For users who have a language server deployed, LSIF will take priority over the language server when LSIF data exists for a repository.
You can upload LSIF data to a Sourcegraph instance using your existing continuous integration infrastructure, or using GitHub Actions.
Go to your global settings at https://sourcegraph.example.com/site-admin/global-settings and enable LSIF:
"codeIntel.lsif": true
After uploading LSIF files, your Sourcegraph instance will use these files to power code intelligence so that when you visit a file in that repository on your Sourcegraph instance, the code intelligence should be more precise than it was out-of-the-box.
When LSIF data does not exist for a particular file in a repository, Sourcegraph will fall back to out-of-the-box code intelligence.
LSIF code intelligence will be out-of-sync when you're viewing a file that has changed since the LSIF data was uploaded.
Global find-references is a resource-intensive operation that's sensitive to the number of packages for which you have uploaded LSIF data into your Sourcegraph instance. Improvements to this are planned for Sourcegraph 3.10 (see the RFC).
Do not upload more than 10-40 LSIF dumps to Sourcegraph instance or you risk harming other parts of Sourcegraph. We are working to validate its performance at scale and eliminate this concern.
To learn more, check out our lightning talk about LSIF from GopherCon 2019 or the introductory blog post: