Paint: prevent RenderResults and Viewers where unappropriate

Using a RenderResult (or a Viewer) was never really working (think you
cant get a real ImBuff from these) -- cannot use it as a clone, stencil
or canvas [Single Image paint texture slot].

In the case of using it as a 2D paint clone image this would also crash
[due to the Image Editor drawing refactor in 2.91].

Now [in the spirit of T73182 / D11179], prevent using these where
unappropriate by using rna pointer polling functions.

Also add a security check for the 2D paint clone image crash in case a
stencil ImBuff cannot be provided for some reason, but generally old
files are now patched in do_versions_after_linking_300 (thx @brecht!).

Fixes T91625.

Maniphest Tasks: T91625

Differential Revision: https://developer.blender.org/D12609

1 files changed, 22 insertions, 0 deletions

diff --git a/source/blender/blenloader/intern/versioning_300.c b/source/blender/blenloader/intern/versioning_300.c
index 9908e231452..0d333ac2edc 100644
--- a/source/blender/blenloader/intern/versioning_300.c
+++ b/source/blender/blenloader/intern/versioning_300.c
@@ -518,6 +518,28 @@ void do_versions_after_linking_300(Main *bmain, ReportList *UNUSED(reports))
   {
     /* Keep this block, even when empty. */
     do_versions_idproperty_ui_data(bmain);
+
+    LISTBASE_FOREACH (Scene *, scene, &bmain->scenes) {
+      ToolSettings *tool_settings = scene->toolsettings;
+      ImagePaintSettings *imapaint = &tool_settings->imapaint;
+      if (imapaint->canvas != NULL &&
+          ELEM(imapaint->canvas->type, IMA_TYPE_R_RESULT, IMA_TYPE_COMPOSITE)) {
+        imapaint->canvas = NULL;
+      }
+      if (imapaint->stencil != NULL &&
+          ELEM(imapaint->stencil->type, IMA_TYPE_R_RESULT, IMA_TYPE_COMPOSITE)) {
+        imapaint->stencil = NULL;
+      }
+      if (imapaint->clone != NULL &&
+          ELEM(imapaint->clone->type, IMA_TYPE_R_RESULT, IMA_TYPE_COMPOSITE)) {
+        imapaint->clone = NULL;
+      }
+    }
+    LISTBASE_FOREACH (Brush *, brush, &bmain->brushes) {
+      if (brush->clone.image != NULL && ELEM(brush->clone.image->type, IMA_TYPE_R_RESULT,
+                                             IMA_TYPE_COMPOSITE)) { brush->clone.image = NULL;
+      }
+    }
   }
 }