Review changes

Signed-off-by: Chris Mark <chrismarkou92@gmail.com>

pkg/commands/edit/add/flagsandargs.go

@@ -54,12 +54,28 @@ func (a *flagsAndArgs) Validate(args []string) error {
 	return nil
 }
 
+// ExpandFileSource normalizes a string list, possibly
+// containing globs, into a validated, globless list.
+// For example, this list:
+//     some/path
+//     some/dir/a*
+//     bfile=some/dir/b*
+// becomes:
+//     some/path
+//     some/dir/airplane
+//     some/dir/ant
+//     some/dir/apple
+//     bfile=some/dir/banana
+// i.e. everything is converted to a key=value pair,
+// where the value is always a relative file path,
+// and the key, if missing, is the same as the value.
+// In the case where the key is explicitly declared,
+// the globbing, if present, must have exactly one match.
 func (a *flagsAndArgs) ExpandFileSource(fSys fs.FileSystem) error {
 	var results []string
-	var key string
 	for _, pattern := range a.FileSources {
 		var patterns []string
-		key = ""
+		key := ""
 		// check if the pattern is in `--from-file=[key=]source` format
 		// and if so split it to send only the file-pattern to glob function
 		s := strings.Split(pattern, "=")
@@ -77,8 +93,8 @@ func (a *flagsAndArgs) ExpandFileSource(fSys fs.FileSystem) error {
 		// and extend it with the `key=` prefix
 		if key != "" {
 			if len(result) != 1 {
-				msg := fmt.Sprintf("%s pattern should not catch more than one file", pattern)
-				return fmt.Errorf(msg)
+				return fmt.Errorf(
+					"'pattern '%s' catches files %v, should catch only one.", pattern, result)
 			}
 			fileSource := fmt.Sprintf("%s=%s", key, result[0])
 			results = append(results, fileSource)