Fix T84935: boolean custom data layers not saved correctly

The issue was that boolean custom data layers were not written to files,
because the dna struct name `bool` does not exist. Adding a struct that
just contains a `bool/uint8_t` does not seem to be possible, it looks like
the minimum dna struct size is 4 bytes.

The proposed solution has two parts:

1. Write the custom data layer using `BLO_write_raw` instead of
   `BLO_write_struct_array_by_name`.
2. When loading a file, reinitialize any custom data layer that was
   not saved correctly (this is just a fix for existing files).

Differential Revision: https://developer.blender.org/D10194

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/customdata.c b/source/blender/blenkernel/intern/customdata.c
index 5d61b1165ed..446ef12574d 100644
--- a/source/blender/blenkernel/intern/customdata.c
+++ b/source/blender/blenkernel/intern/customdata.c
@@ -5104,6 +5104,10 @@ void CustomData_blend_write(BlendWriter *writer,
       const int *layer_data = layer->data;
       BLO_write_raw(writer, sizeof(*layer_data) * count, layer_data);
     }
+    else if (layer->type == CD_PROP_BOOL) {
+      const bool *layer_data = layer->data;
+      BLO_write_raw(writer, sizeof(*layer_data) * count, layer_data);
+    }
     else {
       const char *structname;
       int structnum;
@@ -5193,6 +5197,16 @@ void CustomData_blend_read(BlendDataReader *reader, CustomData *data, int count)
 
     if (CustomData_verify_versions(data, i)) {
       BLO_read_data_address(reader, &layer->data);
+      if (layer->data == NULL) {
+        /* Usually this should never happen, except when a custom data layer has not been written
+         * to a file correctly. */
+        CLOG_WARN(&LOG, "Reallocating custom data layer that was not saved correctly.");
+        const LayerTypeInfo *info = layerType_getInfo(layer->type);
+        layer->data = MEM_calloc_arrayN((size_t)count, info->size, layerType_getName(layer->type));
+        if (info->set_default) {
+          info->set_default(layer->data, count);
+        }
+      }
       if (layer->type == CD_MDISPS) {
         blend_read_mdisps(reader, count, layer->data, layer->flag & CD_FLAG_EXTERNAL);
       }