5 files changed, 19 insertions, 7 deletions
diff --git a/source/blender/bmesh/bmesh_class.h b/source/blender/bmesh/bmesh_class.h
index 0246850123a..9d5737a5b71 100644
--- a/source/blender/bmesh/bmesh_class.h
+++ b/source/blender/bmesh/bmesh_class.h
@@ -265,8 +265,20 @@ typedef struct BMFace {
    * (the length of #BMFace.l_first circular linked list).
    */
   int len;
-  float no[3];  /* face normal */
-  short mat_nr; /* material index */
+  /**
+   * Face normal, see #BM_face_calc_normal.
+   */
+  float no[3];
+  /**
+   * Material index, typically >= 0 and < #Mesh.totcol although this isn't enforced
+   * Python for e.g. can set this to any positive value since scripts may create
+   * mesh data first and setup material slots later.
+   *
+   * When using to index into a material array it's range should be checked first,
+   * values exceeding the range should be ignored or treated as zero
+   * (if a material slot needs to be used - when drawing for e.g.)
+   */
+  short mat_nr;
   //  short _pad[3];
 } BMFace;
 
diff --git a/source/blender/bmesh/intern/bmesh_core.c b/source/blender/bmesh/intern/bmesh_core.c
index d6bf556f14b..4d84d558cd7 100644
--- a/source/blender/bmesh/intern/bmesh_core.c
+++ b/source/blender/bmesh/intern/bmesh_core.c
@@ -1460,7 +1460,7 @@ BMFace *bmesh_kernel_split_face_make_edge(BMesh *bm,
   }
   else {
     /* this code is not significant until holes actually work */
-    // printf("warning: call to split face euler without holes argument; holes will be tossed.\n");
+    // printf("WARNING: call to split face euler without holes argument; holes will be tossed.\n");
     for (lst = f->loops.last; lst != f->loops.first; lst = lst2) {
       lst2 = lst->prev;
       BLI_mempool_free(bm->looplistpool, lst);
diff --git a/source/blender/bmesh/intern/bmesh_mods.c b/source/blender/bmesh/intern/bmesh_mods.c
index 70710edea5c..8b56e08c22b 100644
--- a/source/blender/bmesh/intern/bmesh_mods.c
+++ b/source/blender/bmesh/intern/bmesh_mods.c
@@ -597,7 +597,7 @@ bool BM_face_validate(BMFace *face, FILE *err)
   bool ret = true;
 
   if (face->len == 2) {
-    fprintf(err, "warning: found two-edged face. face ptr: %p\n", face);
+    fprintf(err, "WARNING: found two-edged face. face ptr: %p\n", face);
     fflush(err);
   }
 
diff --git a/source/blender/bmesh/intern/bmesh_polygon.c b/source/blender/bmesh/intern/bmesh_polygon.c
index 9ea16c8b61c..6df446a377c 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.c
+++ b/source/blender/bmesh/intern/bmesh_polygon.c
@@ -415,7 +415,7 @@ void BM_face_calc_tangent_edge_diagonal(const BMFace *f, float r_tangent[3])
   /* In case of degenerate faces. */
   zero_v3(r_tangent);
 
-  /* warning: O(n^2) loop here, take care! */
+  /* WARNING: O(n^2) loop here, take care! */
   float dist_max_sq = 0.0f;
   do {
     BMLoop *l_iter_other = l_iter->next;
@@ -447,7 +447,7 @@ void BM_face_calc_tangent_vert_diagonal(const BMFace *f, float r_tangent[3])
   /* In case of degenerate faces. */
   zero_v3(r_tangent);
 
-  /* warning: O(n^2) loop here, take care! */
+  /* WARNING: O(n^2) loop here, take care! */
   float dist_max_sq = 0.0f;
   do {
     BMLoop *l_iter_other = l_iter->next;
diff --git a/source/blender/bmesh/tools/bmesh_bevel.c b/source/blender/bmesh/tools/bmesh_bevel.c
index 8f32f878c58..fa852cdd6da 100644
--- a/source/blender/bmesh/tools/bmesh_bevel.c
+++ b/source/blender/bmesh/tools/bmesh_bevel.c
@@ -5354,7 +5354,7 @@ static BMEdge *snap_edge_for_center_vmesh_vert(int i,
  * so the arguments bndv_rep_faces is an array of size n_bndv give the freps for each i,
  * and center_frep is the frep for the center.
  *
- * Note: this function is for edge bevels only, at the moment.
+ * NOTE: this function is for edge bevels only, at the moment.
  */
 static void snap_edges_for_vmesh_vert(int i,
                                       int j,