From e2a38c836335266bbd5f77dd95b90b60396304f2 Mon Sep 17 00:00:00 2001
From: Rebecca Stambler <rstambler@golang.org>
Date: Mon, 10 Feb 2020 14:45:18 -0500
Subject: [PATCH] internal/lsp: propagate file invalidations to all views

We were previously only invalidating files if they were contained within
a subdirectory of a view, but we should really be invalidating all files
that are known to a view.

Fixes golang/go#34955

Change-Id: I2eb1476e6b5f74a64dbb6d47459f4009648c720d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/218859
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---
 internal/lsp/cache/session.go | 17 +++++++----------
 internal/lsp/cache/view.go    | 11 ++++++++---
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/internal/lsp/cache/session.go b/internal/lsp/cache/session.go
index 8763c4de6e..77d19f3463 100644
--- a/internal/lsp/cache/session.go
+++ b/internal/lsp/cache/session.go
@@ -290,19 +290,16 @@ func (s *session) DidModifyFiles(ctx context.Context, changes []source.FileModif
 		if s.isOpen(c.URI) && c.OnDisk {
 			continue
 		}
-		for _, view := range s.viewsOf(c.URI) {
+		// Look through all of the session's views, invalidating the file for
+		// all of the views to which it is known.
+		for _, view := range s.views {
 			if view.Ignore(c.URI) {
 				return nil, errors.Errorf("ignored file %v", c.URI)
 			}
-			// If the file change is on-disk and not a create,
-			// make sure the file is known to the view already.
-			if c.OnDisk {
-				switch c.Action {
-				case source.Change, source.Delete:
-					if !view.knownFile(c.URI) {
-						continue
-					}
-				}
+			// Don't propagate changes that are outside of the view's scope
+			// or knowledge.
+			if !view.relevantChange(c) {
+				continue
 			}
 			// Make sure that the file is added to the view.
 			if _, err := view.getFile(c.URI); err != nil {
diff --git a/internal/lsp/cache/view.go b/internal/lsp/cache/view.go
index c034ea5f77..542dedc208 100644
--- a/internal/lsp/cache/view.go
+++ b/internal/lsp/cache/view.go
@@ -391,12 +391,17 @@ func basename(filename string) string {
 	return strings.ToLower(filepath.Base(filename))
 }
 
-// knownFile returns true if the given URI is already a part of the view.
-func (v *view) knownFile(uri span.URI) bool {
+func (v *view) relevantChange(c source.FileModification) bool {
+	if v.contains(c.URI) {
+		return true
+	}
+
+	// Check if the view is already aware of this file.
+	// If so, the change is relevant.
 	v.mu.Lock()
 	defer v.mu.Unlock()
 
-	f, err := v.findFile(uri)
+	f, err := v.findFile(c.URI)
 	return f != nil && err == nil
 }