Resolve flag aliases in failed command routes

internal/commandmeta/metadata.go

@@ -130,9 +130,12 @@ type Result struct {
 
 // ParseOptions makes parser context and streams explicit.
 type ParseOptions struct {
-	Context     context.Context
-	In          io.Reader
-	Out         io.Writer
-	Err         io.Writer
-	FlagAliases []FlagAlias
+	// FlagAliasesForPath selects aliases for the actual parser context when
+	// routing has not already selected one. It overrides FlagAliases when set.
+	FlagAliasesForPath func([]string) []FlagAlias
+	Context            context.Context
+	In                 io.Reader
+	Out                io.Writer
+	Err                io.Writer
+	FlagAliases        []FlagAlias
 }