new_from_source should ref the source object

new_from_source needs to ref the ruby source wrapper, since the
underlying C object will only ref the C source object

also fix some issues in reference handling, and some lint errors

see #384

thanks taylorthurlow

Author: jcupitt

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## master
 
+* `new_from_source` keeps a ref to the source object [taylorthurlow]
+* some fixes to object references system
+
 ## Version 2.2.0 (2023-10-18)
 
 * add `draw_point!` [jcupitt]

VERSION

@@ -1 +1 @@
-2.2.0
+2.2.1

lib/vips/image.rb

@@ -458,7 +458,14 @@ def self.new_from_source source, option_string, **opts
       loader = Vips.vips_foreign_find_load_source source
       raise Vips::Error if loader.nil?
 
-      Vips::Operation.call loader, [source], opts, option_string
+      image = Vips::Operation.call loader, [source], opts, option_string
+
+      # keep a secret ref to the source object ... the libvips loader will
+      # keep a ref to the C source object, but we need the ruby wrapper object
+      # to stay alive too
+      image.references << source
+
+      image
     end
 
     def self.matrix_from_array width, height, array

lib/vips/interpolate.rb

@@ -49,10 +49,10 @@ class ManagedStruct < Vips::Object::ManagedStruct
 
     def initialize name
       name = name.to_s if name.is_a? Symbol
-      ptr = Vips.vips_interpolate_new name
-      raise Vips::Error if ptr.nil?
+      pointer = Vips.vips_interpolate_new name
+      raise Vips::Error if pointer.nil?
 
-      super ptr
+      super(pointer)
     end
   end
 end

lib/vips/mutableimage.rb

@@ -58,7 +58,7 @@ def initialize(image)
       # See also the comment on set_type! before changing this.
       pointer = copy_image.ptr
       ::GObject.g_object_ref pointer
-      super pointer
+      super(pointer)
 
       # and save the copy ready for when we finish mutating
       @image = copy_image

lib/vips/operation.rb

@@ -218,7 +218,7 @@ def initialize value
         raise Vips::Error if value.null?
       end
 
-      super value
+      super(value)
     end
 
     def build
@@ -283,7 +283,7 @@ def set name, value, match_image, flags, gtype, destructive
         value = value.map { |x| Operation.imageize match_image, x }
       end
 
-      super name, value
+      super(name, value)
     end
 
     public
@@ -440,14 +440,12 @@ def self.call name, supplied, optional = {}, option_string = ""
         end
       end
 
-      # collect a list of all input references here
-      references = Set.new
+      # dedupe all input references here
+      deduped_references = Set.new
 
       add_reference = lambda do |x|
         if x.is_a?(Vips::Image)
-          x.references.each do |i|
-            references << i
-          end
+          deduped_references.merge x.references
         end
         false
       end
@@ -482,20 +480,27 @@ def self.call name, supplied, optional = {}, option_string = ""
 
       op = op.build
 
+      # we need an array of references for output objects
+      references = deduped_references.to_a
+
       # attach all input refs to output x
       set_reference = lambda do |x|
+        # stop early if there are no refs to attach
+        return true if references == []
+
         if x.is_a? Vips::Image
-          x.references += references
+          references.each { |i| x.references << i }
         end
+
         false
       end
 
       # get all required results
       result = []
       required_output.each do |details|
-        value = details[:arg_name]
+        value = op.get(details[:arg_name])
         flat_find value, &set_reference
-        result << op.get(value)
+        result << value
       end
 
       # fetch all optional ones

lib/vips/region.rb

@@ -44,10 +44,10 @@ class ManagedStruct < Vips::Object::ManagedStruct
     end
 
     def initialize(name)
-      ptr = Vips.vips_region_new name
-      raise Vips::Error if ptr.null?
+      pointer = Vips.vips_region_new name
+      raise Vips::Error if pointer.null?
 
-      super ptr
+      super(pointer)
     end
 
     def width

lib/vips/sourcecustom.rb

@@ -47,7 +47,7 @@ def initialize
       pointer = Vips.vips_source_custom_new
       raise Vips::Error if pointer.null?
 
-      super pointer
+      super(pointer)
     end
 
     # The block is executed to read data from the source. The interface is

lib/vips/targetcustom.rb

@@ -47,7 +47,7 @@ def initialize
       pointer = Vips.vips_target_custom_new
       raise Vips::Error if pointer.null?
 
-      super pointer
+      super(pointer)
     end
 
     # The block is executed to write data to the source. The interface is

lib/vips/version.rb

@@ -1,3 +1,3 @@
 module Vips
-  VERSION = "2.2.0"
+  VERSION = "2.2.1"
 end