refactor: narrow BasicFile interface — apply ISP to Touch and Directory

Touch and Directory inherited content/from from BaseFile but had no use
for them. Directory worked around this by repurposing content() as a
source-directory path store, which was semantically misleading.

Changes:
- Move content/from down into BaseFile (only File and Symlink need them)
- Move evaluate_absent! up into BasicFile (Touch and Directory need it)
- Move UnsupportedOperation up into BasicFile (validate raises it there)
- Re-parent Touch and Directory to BasicFile directly
- Add Directory#source accessor to replace the content() misuse
- Update DSL#directory to call d.source(...) instead of d.content(...)

All 29 tests continue to pass.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

3 files changed, 53 insertions, 32 deletions

diff --git a/lib/dslkeywords/directory.rb b/lib/dslkeywords/directory.rb
index 402bead..6449d74 100644
--- a/lib/dslkeywords/directory.rb
+++ b/lib/dslkeywords/directory.rb
@@ -5,9 +5,15 @@ require_relative 'file'
 module RCM
   # Manages directories: create, delete/purge, or recursively copy from
   # a source directory. Backup is performed before destructive operations.
-  class Directory < BaseFile
+  # Extends BasicFile directly — Directory has no file content or sourcing,
+  # so it must not inherit content/from from BaseFile (ISP). The source
+  # directory for recursive copy is stored via the separate #source method.
+  class Directory < BasicFile
     def recursively = @recursively = true
 
+    # Set or get the source directory path used for recursive copy.
+    def source(path = nil) = path.nil? ? @source_path : @source_path = path
+
     def evaluate!
       return unless super
 
@@ -35,6 +41,8 @@ module RCM
       end
     end
 
+    # Override BasicFile#evaluate_absent! with directory-specific behaviour:
+    # optionally recursive removal and backup of the whole directory tree.
     def evaluate_absent!
       return unless ::File.directory?(@file_path)
 
@@ -51,20 +59,20 @@ module RCM
     end
 
     def evaluate_present_recursively!
-      source_path = content
-      raise "Source #{source_path} is not a directory!" unless ::File.directory?(source_path)
+      src = source
+      raise "Source #{src} is not a directory!" unless ::File.directory?(src)
 
       if ::File.exist?(@file_path)
         raise "Destination #{@file_path} is not a directory!" unless ::File.directory?(@file_path)
 
-        backup_recursively!(source_path, @file_path) unless @without_backup
+        backup_recursively!(src, @file_path) unless @without_backup
       end
 
-      do? "Copying #{source_path} -> #{@file_path} recursively" do
+      do? "Copying #{src} -> #{@file_path} recursively" do
         if ::File.directory?(@file_path)
-          Dir["#{source_path}/*"].each { FileUtils.cp_r(_1, @file_path) }
+          Dir["#{src}/*"].each { FileUtils.cp_r(_1, @file_path) }
         else
-          FileUtils.cp_r(source_path, @file_path)
+          FileUtils.cp_r(src, @file_path)
         end
       end
     end
@@ -96,7 +104,9 @@ module RCM
       return unless @conds_met
 
       d = Directory.new(file_path)
-      d.content(d.instance_eval(&block))
+      # Use source= for the recursive-copy source path rather than content=,
+      # keeping Directory's interface clean and purpose-named.
+      d.source(d.instance_eval(&block))
       self << d
       d
     end
diff --git a/lib/dslkeywords/file.rb b/lib/dslkeywords/file.rb
index 273968c..dc6f4d0 100644
--- a/lib/dslkeywords/file.rb
+++ b/lib/dslkeywords/file.rb
@@ -9,12 +9,18 @@ require_relative 'file_backup'
 module RCM
   # Base class shared by all file-system resources (files, symlinks,
   # touch, directories). Manages path, state (:present/:absent/:purged),
-  # permissions (mode/owner/group), parent-directory lifecycle, and the
-  # FileBackup mixin.
+  # permissions (mode/owner/group), and parent-directory lifecycle.
+  # Does NOT include content/templating — those belong in BaseFile so
+  # Touch and Directory (which have no file content) don't inherit them.
   class BasicFile < Resource
     include Chained
     include FileBackup
 
+    # Raised by validate when an unsupported DSL option is used.
+    # Defined here so BasicFile#validate can raise it even when the
+    # concrete class does not extend BaseFile.
+    class UnsupportedOperation < StandardError; end
+
     def initialize(file_path)
       super(file_path)
       @file_path = file_path
@@ -37,14 +43,6 @@ module RCM
       true
     end
 
-    def content(text = nil)
-      if text.nil?
-        text = @from == :sourcefile ? ::File.read(@content) : @content
-        return @from == :template ? ERB.new(text).result : text
-      end
-      @content = text.instance_of?(Array) ? text.join("\n") : text
-    end
-
     protected
 
     def permissions!(file_path = path)
@@ -63,6 +61,18 @@ module RCM
             "Unsupported '#{method}' operation #{what} (#{what.class})"
     end
 
+    # Delete the resource and optionally remove orphaned parent directories.
+    # Used by File, Symlink, and Touch; Directory overrides this.
+    def evaluate_absent!
+      if ::File.exist?(@file_path)
+        do? "Deleting #{@file_path}" do
+          backup!(@file_path)
+          ::File.delete(@file_path) if ::File.file?(@file_path)
+        end
+      end
+      cleanup_parent_directory! if @manage_directory
+    end
+
     def create_parent_directory!
       dirname = ::File.dirname(@file_path)
       return if ::File.directory?(dirname)
@@ -109,23 +119,22 @@ module RCM
     end
   end
 
-  # Intermediate base for resources that have file content and support
-  # :sourcefile / :template sourcing, and absent-state deletion.
+  # Intermediate base for resources that carry file content: regular files
+  # and symlinks. Adds content storage with optional ERB templating or
+  # sourcefile reading. Touch and Directory extend BasicFile directly so
+  # they are not burdened with content/from (ISP).
   class BaseFile < BasicFile
-    class UnsupportedOperation < StandardError; end
-
     def from(what) = @from = validate(__method__, what.to_sym, :sourcefile, :template)
 
-    protected
-
-    def evaluate_absent!
-      if ::File.exist?(@file_path)
-        do? "Deleting #{@file_path}" do
-          backup!(@file_path)
-          ::File.delete(@file_path) if ::File.file?(@file_path)
-        end
+    # Return or set the resource's content.
+    # Getter: resolves ERB templates or reads sourcefile on demand.
+    # Setter: stores plain text or joins an array with newlines.
+    def content(text = nil)
+      if text.nil?
+        text = @from == :sourcefile ? ::File.read(@content) : @content
+        return @from == :template ? ERB.new(text).result : text
       end
-      cleanup_parent_directory! if @manage_directory
+      @content = text.instance_of?(Array) ? text.join("\n") : text
     end
   end
 
diff --git a/lib/dslkeywords/touch.rb b/lib/dslkeywords/touch.rb
index d1073f2..27e691b 100644
--- a/lib/dslkeywords/touch.rb
+++ b/lib/dslkeywords/touch.rb
@@ -5,7 +5,9 @@ require_relative 'file'
 module RCM
   # Creates an empty file (touch semantics). Supports the additional
   # :updated state which re-touches the file even when it already exists.
-  class Touch < BaseFile
+  # Extends BasicFile directly — Touch has no file content or sourcing,
+  # so it must not inherit content/from from BaseFile (ISP).
+  class Touch < BasicFile
     def is(what) = @is = validate(__method__, what.to_sym, :present, :absent, :purged, :updated)
 
     def evaluate!