[elastic] [WIP] Try invoke 'go list ...' again if we get nothing from the previous 'go list ...' invoke

The original 'go list ...' invoke has strict limitations about the load
mode, once 'go list ...' failed, we will get nothing about the packages.

For this case, try to invoke 'go list ...' with weaker limitations, like
without any dependency related information query.

Author: Henry Wong

go/packages/golist.go

@@ -653,6 +653,12 @@ func golistDriverLRUCached(cfg *Config, rootsDirs func() *goInfo, words ...strin
 	h.Write([]byte(cfg.Dir))
 	h.Write([]byte(words[len(words)-1]))
 	hashKey := h.Sum32()
+	// If this is a temporary `go list ...` invoke, i.e. without deps information query. Separate it from the cache
+	// mechanism.
+	if cfg.Mode&(NeedImports|NeedTypes|NeedSyntax|NeedTypesInfo) != 0 {
+		res, err := golistDriver(cfg, rootsDirs, words...)
+		return res, err
+	}
 	if val, ok := goListLRUCache.Get(hashKey); ok {
 		res := val.(goListResult)
 		return res.response, res.err

internal/lsp/cache/load.go

@@ -86,6 +86,16 @@ func (v *view) checkMetadata(ctx context.Context, f *goFile) (map[packageID]*met
 	ctx, done := trace.StartSpan(ctx, "packages.Load", telemetry.File.Of(f.filename()))
 	defer done()
 	pkgs, err := packages.Load(v.Config(ctx), fmt.Sprintf("file=%s", f.filename()))
+	// Give another try to load the packages for current file. This time won't parse the imports and anything related to
+	// the dependencies.
+	if len(pkgs) == 0 {
+		cfg := v.Config(ctx)
+		cfg.Tests = false
+		cfg.Mode = packages.NeedName |
+			packages.NeedFiles |
+			packages.NeedCompiledGoFiles
+		pkgs, err = packages.Load(cfg, fmt.Sprintf("file=%s", f.filename()))
+	}
 	if len(pkgs) == 0 {
 		if err == nil {
 			err = errors.Errorf("go/packages.Load: no packages found for %s", f.filename())