Implement a "from" to config files that loads other files

instruction.go

@@ -20,6 +20,7 @@ type LinkInstruction struct {
 
 type YAMLConfig struct {
 	Links []LinkInstruction `yaml:"links"`
+	From  []string          `yaml:"from,omitempty"`
 }
 
 func (instruction *LinkInstruction) Tidy() {
@@ -318,9 +319,76 @@ func ParseYAMLFile(filename, workdir string) ([]LinkInstruction, error) {
 	return expanded, nil
 }
 
+// ParseYAMLFileRecursive parses a YAML file and recursively processes any "From" references
+func ParseYAMLFileRecursive(filename, workdir string) ([]LinkInstruction, error) {
+	visited := make(map[string]bool)
+	return parseYAMLFileRecursive(filename, workdir, visited)
+}
+
+// parseYAMLFileRecursive is the internal recursive function that tracks visited files to prevent cycles
+func parseYAMLFileRecursive(filename, workdir string, visited map[string]bool) ([]LinkInstruction, error) {
+	// Normalize the filename to prevent cycles with different path representations
+	normalizedFilename, err := filepath.Abs(filename)
+	if err != nil {
+		return nil, fmt.Errorf("error normalizing filename: %w", err)
+	}
+
+	// Check for cycles
+	if visited[normalizedFilename] {
+		return nil, fmt.Errorf("circular reference detected: %s", filename)
+	}
+	visited[normalizedFilename] = true
+	defer delete(visited, normalizedFilename)
+
+	// Parse the current file
+	instructions, err := ParseYAMLFile(filename, workdir)
+	if err != nil {
+		return nil, err
+	}
+
+	// Read the file to check for "From" references
+	data, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("error reading YAML file: %w", err)
+	}
+
+	var config YAMLConfig
+	err = yaml.Unmarshal(data, &config)
+	if err != nil {
+		// If parsing as YAMLConfig fails, there are no "From" references to process
+		return instructions, nil
+	}
+
+	// Process "From" references
+	for _, fromFile := range config.From {
+		// Convert relative paths to absolute paths based on the current file's directory
+		fromPath := fromFile
+		if !filepath.IsAbs(fromPath) {
+			currentDir := filepath.Dir(filename)
+			fromPath = filepath.Join(currentDir, fromPath)
+		}
+
+		// Normalize the path
+		fromPath = filepath.Clean(fromPath)
+
+		// Recursively parse the referenced file
+		// Use the directory of the referenced file as the workdir for pattern expansion
+		fromWorkdir := filepath.Dir(fromPath)
+		fromInstructions, err := parseYAMLFileRecursive(fromPath, fromWorkdir, visited)
+		if err != nil {
+			return nil, fmt.Errorf("error parsing referenced file %s: %w", fromFile, err)
+		}
+
+		// Append the instructions from the referenced file
+		instructions = append(instructions, fromInstructions...)
+	}
+
+	return instructions, nil
+}
+
 func ExpandPattern(source, workdir, target string) (links []LinkInstruction, err error) {
 	static, pattern := doublestar.SplitPattern(source)
-	if static == "" {
+	if static == "" || static == "." {
 		static = workdir
 	}
 	LogInfo("Static part: %s", static)