gopls/internal/lsp/cache: use specific mutexes for module data

View.mu was documented as protecting "most mutable state", but in fact
only protected module upgrades and vulns. To be consistent, use specific
mutexes for this data.

Change-Id: I7454ca7548a1f9c9db786eafbb9cbef3961194dd
Reviewed-on: https://go-review.googlesource.com/c/tools/+/459791
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>

gopls/internal/lsp/cache/view.go

@@ -64,19 +64,16 @@ type View struct {
 	explicitGowork       span.URI // explicitGowork: if non-empty, a user-specified go.work location (TODO: deprecate)
 	workspaceInformation          // grab-bag of Go environment information (TODO: cleanup)
 
-	// mu protects most mutable state of the view.
-	//
-	// TODO(rfindley): specify exactly which mutable state is guarded.
-	mu sync.Mutex
-
 	importsState *importsState
 
 	// moduleUpgrades tracks known upgrades for module paths in each modfile.
 	// Each modfile has a map of module name to upgrade version.
-	moduleUpgrades map[span.URI]map[string]string
+	moduleUpgradesMu sync.Mutex
+	moduleUpgrades   map[span.URI]map[string]string
 
 	// vulns maps each go.mod file's URI to its known vulnerabilities.
-	vulns map[span.URI]*govulncheck.Result
+	vulnsMu sync.Mutex
+	vulns   map[span.URI]*govulncheck.Result
 
 	// filesByURI maps URIs to the canonical URI for the file it denotes.
 	// We also keep a set of candidates for a given basename
@@ -997,8 +994,8 @@ func (v *View) IsGoPrivatePath(target string) bool {
 }
 
 func (v *View) ModuleUpgrades(modfile span.URI) map[string]string {
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.moduleUpgradesMu.Lock()
+	defer v.moduleUpgradesMu.Unlock()
 
 	upgrades := map[string]string{}
 	for mod, ver := range v.moduleUpgrades[modfile] {
@@ -1013,8 +1010,8 @@ func (v *View) RegisterModuleUpgrades(modfile span.URI, upgrades map[string]stri
 		return
 	}
 
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.moduleUpgradesMu.Lock()
+	defer v.moduleUpgradesMu.Unlock()
 
 	m := v.moduleUpgrades[modfile]
 	if m == nil {
@@ -1027,8 +1024,8 @@ func (v *View) RegisterModuleUpgrades(modfile span.URI, upgrades map[string]stri
 }
 
 func (v *View) ClearModuleUpgrades(modfile span.URI) {
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.moduleUpgradesMu.Lock()
+	defer v.moduleUpgradesMu.Unlock()
 
 	delete(v.moduleUpgrades, modfile)
 }
@@ -1039,8 +1036,8 @@ var timeNow = time.Now                        // for testing
 func (v *View) Vulnerabilities(modfiles ...span.URI) map[span.URI]*govulncheck.Result {
 	m := make(map[span.URI]*govulncheck.Result)
 	now := timeNow()
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.vulnsMu.Lock()
+	defer v.vulnsMu.Unlock()
 
 	if len(modfiles) == 0 { // empty means all modfiles
 		for modfile := range v.vulns {
@@ -1059,8 +1056,8 @@ func (v *View) Vulnerabilities(modfiles ...span.URI) map[span.URI]*govulncheck.R
 }
 
 func (v *View) SetVulnerabilities(modfile span.URI, vulns *govulncheck.Result) {
-	v.mu.Lock()
-	defer v.mu.Unlock()
+	v.vulnsMu.Lock()
+	defer v.vulnsMu.Unlock()
 
 	v.vulns[modfile] = vulns
 }