Fix T91197: marking assets from Python may crash

When using `asset_mark` function from a Python script and afterwards
updating the preview image, a crash might happen. The preview image is
generated by the `asset_mark` function. This may happen on a background
thread, introducing potential synchronization issues.

This patch fixes this by separating the preview generation
`ID.asset_generate_preview` from the mark as asset `ID.asset_mark`.

Note: this separation of "mark as asset" and "generate preview" also
applies to the `ED_asset_mark_id()` C function; if it is desired to have
previews rendered after marking as asset, a call to
`ED_asset_generate_preview()` is now also required.

Reviewed By: sybren

Maniphest Tasks: T91197

Differential Revision: https://developer.blender.org/D12922

1 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/editors/asset/ED_asset_mark_clear.h b/source/blender/editors/asset/ED_asset_mark_clear.h
index d8b8f15a109..bab1d1bf8a5 100644
--- a/source/blender/editors/asset/ED_asset_mark_clear.h
+++ b/source/blender/editors/asset/ED_asset_mark_clear.h
@@ -34,7 +34,14 @@ struct bContext;
  *
  * \return whether the datablock was marked as asset; false when it is not capable of becoming an
  * asset, or when it already was an asset. */
-bool ED_asset_mark_id(const struct bContext *C, struct ID *id);
+bool ED_asset_mark_id(struct ID *id);
+
+/**
+ * Generate preview image for the given datablock.
+ *
+ * The preview image might be generated using a background thread.
+ */
+void ED_asset_generate_preview(const struct bContext *C, struct ID *id);
 
 /**
  * Remove the asset metadata, turning the ID into a "normal" ID.