tree 3e016108150bb710ce0d6f890d43d0597038560d
parent a9663296b157820bf8a4c5470082285cf955da61
author Rob Findley <rfindley@google.com> 1605213021 -0500
committer Robert Findley <rfindley@google.com> 1606231329 +0000

internal/lsp: track diagnostics by reporting source

Our handling of diagnostics has gotten complicated and has recently been
a source of bugs. Heschi and I took a step back and refactored the
diagnostic pass, starting with a new data structure for tracking
diagnostics.

The LSP server now holds a map of URI to collection of diagnostic
reports, which is used to track diagnostics as they are computed by
multiple sources. Additionally, this collection holds a hash of the
last published diagnostic set.

This new information allows us to implement an algorithm for
incrementally updating diagnostics on the server: diagnostics reports
are stored as they are computed for a snapshot, and then published in
(possibly multiple) passes, with the last pass for a snapshot being
marked as 'final'.  In non-final passes, 'publishReports' publishes any
diagnostics that have already been computed for the snapshot, but does
nothing with URIs for which no diagnostics have been computed. In final
passes all diagnostics are reported, with empty diagnostics being
published for any URIs with no diagnostic reports. Any URIs for which no
diagnostic reports were computed are pruned from the diagnostic set. In
all cases, tracking the hash of published diagnostics prevents us from
duplicate publication.

This enables some simplifications of the existing diagnostic logic.
Computing new diagnostics and tracking send diagnostics is now handled
by the same algorithm, avoiding some bookkeeping. It is also no longer
necessary to explicitly clear diagnostics for deletions. This fixes some
previously broken edge cases, for example when packages go out of scope
due to go.mod or gopls.mod changes.

Fixes golang/go#42198

Change-Id: Id0d8d0f7a60f6ffa8c33f0ae41763461f61dab7b
Reviewed-on: https://go-review.googlesource.com/c/tools/+/269677
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Trust: Robert Findley <rfindley@google.com>