fix [#30865] Crash when browsing last operators in outliner (or by Python API)

Operator descriptions can be NULL pointers,
fix this by making use of PROP_NEVER_NULL flag, when its not set, generated string funcs will test for NULL.

5 files changed, 30 insertions, 1 deletions

diff --git a/source/blender/makesrna/RNA_types.h b/source/blender/makesrna/RNA_types.h
index 8a668f68761..8f3e2c1f104 100644
--- a/source/blender/makesrna/RNA_types.h
+++ b/source/blender/makesrna/RNA_types.h
@@ -180,6 +180,9 @@ typedef enum PropertyFlag {
 	/* disallow assigning a variable to its self, eg an object tracking its self
 	 * only apply this to types that are derived from an ID ()*/
 	PROP_ID_SELF_CHECK = 1<<20,
+	/* use for...
+	 * - pointers: in the UI and python so unsetting or setting to None won't work
+	 * - strings: so our internal generated get/length/set functions know to do NULL checks before access [#30865] */
 	PROP_NEVER_NULL = 1<<18,
 	/* currently only used for UI, this is similar to PROP_NEVER_NULL
 	 * except that the value may be NULL at times, used for ObData, where an Empty's will be NULL
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 02917f1bce8..87f00dc835d 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -539,6 +539,14 @@ static char *rna_def_property_get_func(FILE *f, StructRNA *srna, PropertyRNA *pr
 				            "BLI_strncpy" : "BLI_strncpy_utf8";
 
 				rna_print_data_get(f, dp);
+
+				if (!(prop->flag & PROP_NEVER_NULL)) {
+					fprintf(f, "	if (data->%s == NULL) {\n", dp->dnaname);
+					fprintf(f, "		*value = '\\0';\n");
+					fprintf(f, "		return;\n");
+					fprintf(f, "	}\n");
+				}
+
 				if (sprop->maxlength)
 					fprintf(f, "	%s(value, data->%s, %d);\n", string_copy_func, dp->dnaname, sprop->maxlength);
 				else
@@ -781,6 +789,13 @@ static char *rna_def_property_set_func(FILE *f, StructRNA *srna, PropertyRNA *pr
 				            "BLI_strncpy" : "BLI_strncpy_utf8";
 
 				rna_print_data_get(f, dp);
+
+				if (!(prop->flag & PROP_NEVER_NULL)) {
+					fprintf(f, "	if (data->%s == NULL) {\n", dp->dnaname);
+					fprintf(f, "		return;\n");
+					fprintf(f, "	}\n");
+				}
+
 				if (sprop->maxlength)
 					fprintf(f, "	%s(data->%s, value, %d);\n", string_copy_func, dp->dnaname, sprop->maxlength);
 				else
@@ -956,6 +971,9 @@ static char *rna_def_property_length_func(FILE *f, StructRNA *srna, PropertyRNA
 		}
 		else {
 			rna_print_data_get(f, dp);
+			if (!(prop->flag & PROP_NEVER_NULL)) {
+				fprintf(f, "	if (data->%s == NULL) return 0;\n", dp->dnaname);
+			}
 			fprintf(f, "	return strlen(data->%s);\n", dp->dnaname);
 		}
 		fprintf(f, "}\n\n");
diff --git a/source/blender/makesrna/intern/rna_define.c b/source/blender/makesrna/intern/rna_define.c
index e106f8236c9..abaf598d4cc 100644
--- a/source/blender/makesrna/intern/rna_define.c
+++ b/source/blender/makesrna/intern/rna_define.c
@@ -949,7 +949,6 @@ PropertyRNA *RNA_def_property(StructOrFunctionRNA *cont_, const char *identifier
 			StringPropertyRNA *sprop = (StringPropertyRNA*)prop;
 
 			sprop->defaultvalue = "";
-			sprop->maxlength = 0;
 			break;
 		}
 		case PROP_ENUM:
@@ -983,6 +982,12 @@ PropertyRNA *RNA_def_property(StructOrFunctionRNA *cont_, const char *identifier
 			prop->flag |= PROP_ANIMATABLE;
 	}
 
+	if (type == PROP_STRING) {
+		/* used so generated 'get/length/set' functions skip a NULL check
+		 * in some cases we want it */
+		RNA_def_property_flag(prop, PROP_NEVER_NULL);
+	}
+
 	if (DefRNA.preprocess) {
 		switch (type) {
 			case PROP_BOOLEAN:
diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index a70eac58142..635dfb48b27 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -840,6 +840,7 @@ static void rna_def_menu(BlenderRNA *brna)
 	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_Menu_bl_description_set");
 	/* RNA_def_property_clear_flag(prop, PROP_EDITABLE); */
 	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
+	RNA_def_property_clear_flag(prop, PROP_NEVER_NULL); /* check for NULL */
 
 	RNA_define_verify_sdna(1);
 }
diff --git a/source/blender/makesrna/intern/rna_wm.c b/source/blender/makesrna/intern/rna_wm.c
index 80dad69f124..db77be8dc31 100644
--- a/source/blender/makesrna/intern/rna_wm.c
+++ b/source/blender/makesrna/intern/rna_wm.c
@@ -1296,6 +1296,7 @@ static void rna_def_operator(BlenderRNA *brna)
 	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_Operator_bl_description_set");
 	/* RNA_def_property_clear_flag(prop, PROP_EDITABLE); */
 	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
+	RNA_def_property_clear_flag(prop, PROP_NEVER_NULL); /* check for NULL */
 
 	prop = RNA_def_property(srna, "bl_options", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "type->flag");
@@ -1362,6 +1363,7 @@ static void rna_def_macro_operator(BlenderRNA *brna)
 	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_Operator_bl_description_set");
 	/* RNA_def_property_clear_flag(prop, PROP_EDITABLE); */
 	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
+	RNA_def_property_clear_flag(prop, PROP_NEVER_NULL); /* check for NULL */
 
 	prop = RNA_def_property(srna, "bl_options", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "type->flag");