[gimp] Issue #1450 - Transform tools don't add an alpha channel in 'None' interpolation

[Michael Natterer <mitch src gnome org>]

commit 756fed0cc21be56ff7925da98622d7ca382ede38
Author: Michael Natterer <mitch gimp org>
Date:   Fri Jun 15 11:33:10 2018 +0200

    Issue #1450 - Transform tools don't add an alpha channel in 'None' interpolation
    
    Never add an alpha channel in gimp_layer_real_transform(), it was only
    added because our pre-GEGL transform code was shit. This is quite the
    opposite of what the bug reporter asked for, but IMO the more correct
    fix.
    
    This will NOT go to 2.10 because it changes behavior.

 app/core/gimplayer.c | 5 -----
 1 file changed, 5 deletions(-)
---
diff --git a/app/core/gimplayer.c b/app/core/gimplayer.c
index 0b25e79f1f..d19e1181b2 100644
--- a/app/core/gimplayer.c
+++ b/app/core/gimplayer.c
@@ -1654,11 +1654,6 @@ gimp_layer_real_transform (GimpLayer              *layer,
                            GimpTransformResize     clip_result,
                            GimpProgress           *progress)
 {
-  /* FIXME: make interpolated transformations work on layers without alpha */
-  if (interpolation_type != GIMP_INTERPOLATION_NONE &&
-      ! gimp_drawable_has_alpha (GIMP_DRAWABLE (layer)))
-    gimp_layer_add_alpha (layer);
-
   GIMP_ITEM_CLASS (parent_class)->transform (GIMP_ITEM (layer),
                                              context, matrix, direction,
                                              interpolation_type,