raise errors when ambiguous env id uses legacy format

cmd/esc/cli/env_clone.go

@@ -37,17 +37,23 @@ func newEnvCloneCmd(env *envCommand) *cobra.Command {
 				return err
 			}
 
-			ref := env.parseRef(args[0])
-			if ref.isUsingLegacyID {
-				return errors.New("invalid source environment ID")
+			ref, args, err := env.getExistingEnvRef(ctx, args)
+			// An error will arise if an environment reference is ambiguous and can't be
+			// resolved to a single environment. The ref for the non-legacy environment will
+			// also be returned in this case.
+			// If the original ref is using a legacy ID of just env name return an error
+			// Otherwise we will ignore any conflict errors and assume the user meant <project-name>/<env-name>
+			if (err != nil && ref.isUsingLegacyID) || ref.isUsingLegacyID {
+				return errors.New("source environment ID must be at least <project-name>/<env-name>")
 			}
+
 			if ref.version != "" {
 				return errors.New("the clone command does not accept versions")
 			}
 
 			var destProject string
-			destName := args[1]
-			if project, name, hasDelimiter := strings.Cut(args[1], "/"); hasDelimiter {
+			destName := args[0]
+			if project, name, hasDelimiter := strings.Cut(args[0], "/"); hasDelimiter {
 				destProject = project
 				destName = name
 			}