internal/lsp: invalidate package on go.mod change with go.work

If a go.mod file is updated, the packages
in that module may have updated type check
errors since the go version can affect errors.

Fixes golang/go#51732

Change-Id: I3a8cd8b9ab267336ccc5c841a14c5ec5f6c986e5
Reviewed-on: https://go-review.googlesource.com/c/tools/+/393534
Trust: Suzy Mueller <suzmue@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

gopls/internal/regtest/diagnostics/diagnostics_test.go

@@ -2199,7 +2199,41 @@ package main
 func F[T any](_ T) {
 }
 `
-	Run(t, files, func(t *testing.T, env *Env) { // Create a new workspace-level directory and empty file.
+	Run(t, files, func(_ *testing.T, env *Env) { // Create a new workspace-level directory and empty file.
+		var d protocol.PublishDiagnosticsParams
+		env.Await(
+			OnceMet(
+				env.DiagnosticAtRegexpWithMessage("main.go", `T any`, "type parameters require"),
+				ReadDiagnostics("main.go", &d),
+			),
+		)
+
+		env.ApplyQuickFixes("main.go", d.Diagnostics)
+
+		env.Await(
+			EmptyDiagnostics("main.go"),
+		)
+	})
+}
+
+func TestEditGoDirectiveWorkspace(t *testing.T) {
+	testenv.NeedsGo1Point(t, 18)
+	const files = `
+-- go.mod --
+module mod.com
+
+go 1.16
+-- go.work --
+go 1.18
+
+use .
+-- main.go --
+package main
+
+func F[T any](_ T) {
+}
+`
+	Run(t, files, func(_ *testing.T, env *Env) { // Create a new workspace-level directory and empty file.
 		var d protocol.PublishDiagnosticsParams
 		env.Await(
 			OnceMet(

internal/lsp/cache/workspace.go

@@ -301,27 +301,27 @@ func (w *workspace) invalidate(ctx context.Context, changes map[span.URI]*fileCh
 	// we need to either re-read it if it exists or walk the filesystem if it
 	// has been deleted. go.work should override the gopls.mod if both exist.
 	changed, reload = handleWorkspaceFileChanges(ctx, result, changes, fs)
-	// Next, handle go.mod changes that could affect our workspace. If we're
-	// reading our tracked modules from the gopls.mod, there's nothing to do
-	// here.
-	if result.moduleSource != goplsModWorkspace && result.moduleSource != goWorkWorkspace {
-		for uri, change := range changes {
-			// Otherwise, we only care about go.mod files in the workspace directory.
-			if change.isUnchanged || !isGoMod(uri) || !source.InDir(result.root.Filename(), uri.Filename()) {
-				continue
-			}
-			changed = true
-			active := result.moduleSource != legacyWorkspace || source.CompareURI(modURI(w.root), uri) == 0
-			reload = reload || (active && change.fileHandle.Saved())
-			if change.exists {
-				result.knownModFiles[uri] = struct{}{}
-				if active {
-					result.activeModFiles[uri] = struct{}{}
-				}
-			} else {
-				delete(result.knownModFiles, uri)
-				delete(result.activeModFiles, uri)
+	// Next, handle go.mod changes that could affect our workspace.
+	for uri, change := range changes {
+		// Otherwise, we only care about go.mod files in the workspace directory.
+		if change.isUnchanged || !isGoMod(uri) || !source.InDir(result.root.Filename(), uri.Filename()) {
+			continue
+		}
+		changed = true
+		active := result.moduleSource != legacyWorkspace || source.CompareURI(modURI(w.root), uri) == 0
+		reload = reload || (active && change.fileHandle.Saved())
+		// Don't mess with the list of mod files if using go.work or gopls.mod.
+		if result.moduleSource == goplsModWorkspace || result.moduleSource == goWorkWorkspace {
+			continue
+		}
+		if change.exists {
+			result.knownModFiles[uri] = struct{}{}
+			if active {
+				result.activeModFiles[uri] = struct{}{}
 			}
+		} else {
+			delete(result.knownModFiles, uri)
+			delete(result.activeModFiles, uri)
 		}
 	}