🐛 Verify valid shows.yml

Fix nil pointer derference

convids/logic.go

@@ -18,6 +18,14 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+type ShowWalker func(show *Show, path string) error
+type GroupPrinter func(name string, group Shows)
+
+var ErrNoFiles = errors.New("no files processed")
+var ErrSkipped = errors.New("skipped")
+var ErrMissingConfig = errors.New("missing config")
+var ErrMissingShows = errors.New("missing shows")
+
 func NewData(path string) (*Data, error) {
 	//nolint:gosec // I don't care if this is user input
 	f, err := os.Open(path)
@@ -27,7 +35,17 @@ func NewData(path string) (*Data, error) {
 	ydec := yaml.NewDecoder(f)
 	var data Data
 	err = ydec.Decode(&data)
-	return &data, err
+	if err != nil {
+		return nil, err
+	}
+
+	if data.Config == nil {
+		return nil, ErrMissingConfig
+	}
+	if data.Shows == nil || len(*(data.Shows)) == 0 {
+		return nil, ErrMissingShows
+	}
+	return &data, nil
 }
 
 func ensureExtRe(c *Config) (err error) {
@@ -38,12 +56,6 @@ func ensureExtRe(c *Config) (err error) {
 	return
 }
 
-type ShowWalker func(show *Show, path string) error
-type GroupPrinter func(name string, group Shows)
-
-var ErrNoFiles = errors.New("no files processed")
-var ErrSkipped = errors.New("skipped")
-
 type processInput struct {
 	file   os.DirEntry
 	source string