lib/scanner, lib/fs: Don't create file infos with abs paths (fixes #4799) (#4800)

lib/model/model.go

@@ -2784,7 +2784,12 @@ func unifySubs(dirs []string, exists func(dir string) bool) []string {
 	}
 	prev := "./" // Anything that can't be parent of a clean path
 	for i := 0; i < len(dirs); {
-		dir := filepath.Clean(dirs[i])
+		dir, err := fs.Canonicalize(dirs[i])
+		if err != nil {
+			l.Debugf("Skipping %v for scan: %s", dirs[i], err)
+			dirs = append(dirs[:i], dirs[i+1:]...)
+			continue
+		}
 		if dir == prev || strings.HasPrefix(dir, prev+string(fs.PathSeparator)) {
 			dirs = append(dirs[:i], dirs[i+1:]...)
 			continue

lib/model/model_test.go

@@ -2159,6 +2159,12 @@ func unifySubsCases() []unifySubsCase {
 			[]string{"foo"},
 			nil,
 		},
+		{
+			// 10. absolute path
+			[]string{"/foo"},
+			[]string{"foo"},
+			[]string{"foo"},
+		},
 	}
 
 	if runtime.GOOS == "windows" {