From aa62c1b5d1d57977442786b7676ea3f36b4ffe33 Mon Sep 17 00:00:00 2001
From: Hans Goudey <hans@blender.org>
Date: Sun, 3 Nov 2024 10:48:39 +0100
Subject: [PATCH] Fix #129741: Two issues creating GPU shader from Python

1. Log printing casted a span of `StringRefNull` to a span of `char **`
2. Creating the shader tried to create `StringRefNull` from `nullptr`.
---
 source/blender/gpu/intern/gpu_shader_log.cc | 11 ++++++-----
 source/blender/python/gpu/gpu_py_shader.cc  | 20 ++++++++++++++------
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/source/blender/gpu/intern/gpu_shader_log.cc b/source/blender/gpu/intern/gpu_shader_log.cc
index 6b8a9c49a1d..01ef65dc1aa 100644
--- a/source/blender/gpu/intern/gpu_shader_log.cc
+++ b/source/blender/gpu/intern/gpu_shader_log.cc
@@ -21,6 +21,8 @@
 
 #include "CLG_log.h"
 
+#include "fmt/format.h"
+
 static CLG_LogRef LOG = {"gpu.shader"};
 
 namespace blender::gpu {
@@ -48,7 +50,7 @@ void Shader::print_log(Span<StringRefNull> sources,
   char warn_col[] = "\033[33;1m";
   char info_col[] = "\033[0;2m";
   char reset_col[] = "\033[0;0m";
-  char *sources_combined = BLI_string_join_arrayN((const char **)sources.data(), sources.size());
+  std::string sources_combined = fmt::to_string(fmt::join(sources, ""));
   DynStr *dynstr = BLI_dynstr_new();
 
   if (!CLG_color_support_get(&LOG)) {
@@ -106,7 +108,7 @@ void Shader::print_log(Span<StringRefNull> sources,
     }
 
     GPULogItem log_item;
-    log_line = parser->parse_line(sources_combined, log_line, log_item);
+    log_line = parser->parse_line(sources_combined.c_str(), log_line, log_item);
 
     /* Empty line, skip. */
     if ((log_item.cursor.row == -1) && ELEM(log_line[0], '\n', '\0')) {
@@ -126,7 +128,7 @@ void Shader::print_log(Span<StringRefNull> sources,
       found_line_id = false;
     }
 
-    const char *src_line = sources_combined;
+    const char *src_line = sources_combined.c_str();
 
     /* Separate from previous block. */
     if (previous_location.source != log_item.cursor.source ||
@@ -251,14 +253,13 @@ void Shader::print_log(Span<StringRefNull> sources,
       (severity >= CLG_SEVERITY_WARN))
   {
     if (DEBUG_LOG_SHADER_SRC_ON_ERROR && error) {
-      CLG_log_str(LOG.type, severity, this->name, stage, sources_combined);
+      CLG_log_str(LOG.type, severity, this->name, stage, sources_combined.c_str());
     }
     const char *_str = BLI_dynstr_get_cstring(dynstr);
     CLG_log_str(LOG.type, severity, this->name, stage, _str);
     MEM_freeN((void *)_str);
   }
 
-  MEM_freeN(sources_combined);
   BLI_dynstr_free(dynstr);
 }
 
diff --git a/source/blender/python/gpu/gpu_py_shader.cc b/source/blender/python/gpu/gpu_py_shader.cc
index db2e6f1c589..f9f4928e815 100644
--- a/source/blender/python/gpu/gpu_py_shader.cc
+++ b/source/blender/python/gpu/gpu_py_shader.cc
@@ -97,6 +97,14 @@ static int pygpu_shader_uniform_location_get(GPUShader *shader,
 /** \name Shader Type
  * \{ */
 
+static std::optional<blender::StringRefNull> c_str_to_stringref_opt(const char *str)
+{
+  if (!str) {
+    return std::nullopt;
+  }
+  return blender::StringRefNull(str);
+}
+
 static PyObject *pygpu_shader__tp_new(PyTypeObject * /*type*/, PyObject *args, PyObject *kwds)
 {
   BPYGPU_IS_INIT_OR_ERROR_OBJ;
@@ -138,12 +146,12 @@ static PyObject *pygpu_shader__tp_new(PyTypeObject * /*type*/, PyObject *args, P
     return nullptr;
   }
 
-  GPUShader *shader = GPU_shader_create_from_python(params.vertexcode,
-                                                    params.fragcode,
-                                                    params.geocode,
-                                                    params.libcode,
-                                                    params.defines,
-                                                    params.name);
+  GPUShader *shader = GPU_shader_create_from_python(c_str_to_stringref_opt(params.vertexcode),
+                                                    c_str_to_stringref_opt(params.fragcode),
+                                                    c_str_to_stringref_opt(params.geocode),
+                                                    c_str_to_stringref_opt(params.libcode),
+                                                    c_str_to_stringref_opt(params.defines),
+                                                    c_str_to_stringref_opt(params.name));
 
   if (shader == nullptr) {
     PyErr_SetString(PyExc_Exception, "Shader Compile Error, see console for more details");