BLI_path: remove trailing NULL argument to BLI_path_join

Using varargs had the disadvantages, replace with a macro which has
some advantages.

- Arguments are type checked.
- Less verbose.
- Unintended NULL arguments would silently terminate joining paths.
- Passing in a NULL argument warns with GCC.

23 files changed, 184 insertions, 111 deletions

diff --git a/intern/mantaflow/intern/MANTA_main.cpp b/intern/mantaflow/intern/MANTA_main.cpp
index f5f22dc700b..ae584e6e590 100644
--- a/intern/mantaflow/intern/MANTA_main.cpp
+++ b/intern/mantaflow/intern/MANTA_main.cpp
@@ -1507,13 +1507,9 @@ bool MANTA::bakeData(FluidModifierData *fmd, int framenr)
 
   string volume_format = getCacheFileEnding(fds->cache_data_format);
 
+  BLI_path_join(cacheDirData, sizeof(cacheDirData), fds->cache_directory, FLUID_DOMAIN_DIR_DATA);
   BLI_path_join(
-      cacheDirData, sizeof(cacheDirData), fds->cache_directory, FLUID_DOMAIN_DIR_DATA, nullptr);
-  BLI_path_join(cacheDirGuiding,
-                sizeof(cacheDirGuiding),
-                fds->cache_directory,
-                FLUID_DOMAIN_DIR_GUIDE,
-                nullptr);
+      cacheDirGuiding, sizeof(cacheDirGuiding), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE);
   BLI_path_make_safe(cacheDirData);
   BLI_path_make_safe(cacheDirGuiding);
 
@@ -1540,7 +1536,7 @@ bool MANTA::bakeNoise(FluidModifierData *fmd, int framenr)
   string volume_format = getCacheFileEnding(fds->cache_data_format);
 
   BLI_path_join(
-      cacheDirNoise, sizeof(cacheDirNoise), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE, nullptr);
+      cacheDirNoise, sizeof(cacheDirNoise), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE);
   BLI_path_make_safe(cacheDirNoise);
 
   ss.str("");
@@ -1566,8 +1562,7 @@ bool MANTA::bakeMesh(FluidModifierData *fmd, int framenr)
   string volume_format = getCacheFileEnding(fds->cache_data_format);
   string mesh_format = getCacheFileEnding(fds->cache_mesh_format);
 
-  BLI_path_join(
-      cacheDirMesh, sizeof(cacheDirMesh), fds->cache_directory, FLUID_DOMAIN_DIR_MESH, nullptr);
+  BLI_path_join(cacheDirMesh, sizeof(cacheDirMesh), fds->cache_directory, FLUID_DOMAIN_DIR_MESH);
   BLI_path_make_safe(cacheDirMesh);
 
   ss.str("");
@@ -1596,8 +1591,7 @@ bool MANTA::bakeParticles(FluidModifierData *fmd, int framenr)
   BLI_path_join(cacheDirParticles,
                 sizeof(cacheDirParticles),
                 fds->cache_directory,
-                FLUID_DOMAIN_DIR_PARTICLES,
-                nullptr);
+                FLUID_DOMAIN_DIR_PARTICLES);
   BLI_path_make_safe(cacheDirParticles);
 
   ss.str("");
@@ -1623,11 +1617,8 @@ bool MANTA::bakeGuiding(FluidModifierData *fmd, int framenr)
   string volume_format = getCacheFileEnding(fds->cache_data_format);
   string resumable_cache = !(fds->flags & FLUID_DOMAIN_USE_RESUMABLE_CACHE) ? "False" : "True";
 
-  BLI_path_join(cacheDirGuiding,
-                sizeof(cacheDirGuiding),
-                fds->cache_directory,
-                FLUID_DOMAIN_DIR_GUIDE,
-                nullptr);
+  BLI_path_join(
+      cacheDirGuiding, sizeof(cacheDirGuiding), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE);
   BLI_path_make_safe(cacheDirGuiding);
 
   ss.str("");
@@ -1678,13 +1669,11 @@ bool MANTA::exportSmokeScript(FluidModifierData *fmd)
 
   FluidDomainSettings *fds = fmd->domain;
 
-  BLI_path_join(
-      cacheDir, sizeof(cacheDir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT, nullptr);
+  BLI_path_join(cacheDir, sizeof(cacheDir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT);
   BLI_path_make_safe(cacheDir);
   /* Create 'script' subdir if it does not exist already */
   BLI_dir_create_recursive(cacheDir);
-  BLI_path_join(
-      cacheDirScript, sizeof(cacheDirScript), cacheDir, FLUID_DOMAIN_SMOKE_SCRIPT, nullptr);
+  BLI_path_join(cacheDirScript, sizeof(cacheDirScript), cacheDir, FLUID_DOMAIN_SMOKE_SCRIPT);
   BLI_path_make_safe(cacheDir);
 
   bool noise = fds->flags & FLUID_DOMAIN_USE_NOISE;
@@ -1791,13 +1780,11 @@ bool MANTA::exportLiquidScript(FluidModifierData *fmd)
 
   FluidDomainSettings *fds = fmd->domain;
 
-  BLI_path_join(
-      cacheDir, sizeof(cacheDir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT, nullptr);
+  BLI_path_join(cacheDir, sizeof(cacheDir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT);
   BLI_path_make_safe(cacheDir);
   /* Create 'script' subdir if it does not exist already */
   BLI_dir_create_recursive(cacheDir);
-  BLI_path_join(
-      cacheDirScript, sizeof(cacheDirScript), cacheDir, FLUID_DOMAIN_LIQUID_SCRIPT, nullptr);
+  BLI_path_join(cacheDirScript, sizeof(cacheDirScript), cacheDir, FLUID_DOMAIN_LIQUID_SCRIPT);
   BLI_path_make_safe(cacheDirScript);
 
   bool mesh = fds->flags & FLUID_DOMAIN_USE_MESH;
@@ -2323,8 +2310,7 @@ bool MANTA::hasGuiding(FluidModifierData *fmd, int framenr, bool sourceDomain)
 string MANTA::getDirectory(FluidModifierData *fmd, string subdirectory)
 {
   char directory[FILE_MAX];
-  BLI_path_join(
-      directory, sizeof(directory), fmd->domain->cache_directory, subdirectory.c_str(), nullptr);
+  BLI_path_join(directory, sizeof(directory), fmd->domain->cache_directory, subdirectory.c_str());
   BLI_path_make_safe(directory);
   return directory;
 }
diff --git a/source/blender/blenkernel/intern/appdir.c b/source/blender/blenkernel/intern/appdir.c
index b2f1e75cd1d..21750980b53 100644
--- a/source/blender/blenkernel/intern/appdir.c
+++ b/source/blender/blenkernel/intern/appdir.c
@@ -191,7 +191,7 @@ bool BKE_appdir_folder_documents(char *dir)
 
   char try_documents_path[FILE_MAXDIR];
   /* Own attempt at getting a valid Documents path. */
-  BLI_path_join(try_documents_path, sizeof(try_documents_path), home_path, N_("Documents"), NULL);
+  BLI_path_join(try_documents_path, sizeof(try_documents_path), home_path, N_("Documents"));
   if (!BLI_is_dir(try_documents_path)) {
     return false;
   }
@@ -214,11 +214,11 @@ bool BKE_appdir_folder_caches(char *r_path, const size_t path_len)
 
 #ifdef WIN32
   BLI_path_join(
-      r_path, path_len, caches_root_path, "Blender Foundation", "Blender", "Cache", SEP_STR, NULL);
+      r_path, path_len, caches_root_path, "Blender Foundation", "Blender", "Cache", SEP_STR);
 #elif defined(__APPLE__)
-  BLI_path_join(r_path, path_len, caches_root_path, "Blender", SEP_STR, NULL);
+  BLI_path_join(r_path, path_len, caches_root_path, "Blender", SEP_STR);
 #else /* __linux__ */
-  BLI_path_join(r_path, path_len, caches_root_path, "blender", SEP_STR, NULL);
+  BLI_path_join(r_path, path_len, caches_root_path, "blender", SEP_STR);
 #endif
 
   return true;
@@ -281,7 +281,9 @@ static bool test_path(char *targetpath,
 
   /* Only the last argument should be NULL. */
   BLI_assert(!(folder_name == NULL && (subfolder_name != NULL)));
-  BLI_path_join(targetpath, targetpath_len, path_base, folder_name, subfolder_name, NULL);
+  const char *path_array[] = {path_base, folder_name, subfolder_name};
+  const int path_array_num = (folder_name ? (subfolder_name ? 3 : 2) : 1);
+  BLI_path_join_array(targetpath, targetpath_len, path_array, path_array_num);
   if (check_is_dir == false) {
     CLOG_INFO(&LOG, 3, "using without test: '%s'", targetpath);
     return true;
@@ -365,7 +367,9 @@ static bool get_path_local_ex(char *targetpath,
             STR_OR_FALLBACK(subfolder_name));
 
   if (folder_name) { /* `subfolder_name` may be NULL. */
-    BLI_path_join(relfolder, sizeof(relfolder), folder_name, subfolder_name, NULL);
+    const char *path_array[] = {folder_name, subfolder_name};
+    const int path_array_num = subfolder_name ? 2 : 1;
+    BLI_path_join_array(relfolder, sizeof(relfolder), path_array, path_array_num);
   }
   else {
     relfolder[0] = '\0';
@@ -379,8 +383,7 @@ static bool get_path_local_ex(char *targetpath,
    * we must move the blender_version dir with contents to Resources.
    * Add 4 + 9 for the temporary `/../` path & `Resources`. */
   char osx_resourses[FILE_MAX + 4 + 9];
-  BLI_path_join(
-      osx_resourses, sizeof(osx_resourses), g_app.program_dirname, "..", "Resources", NULL);
+  BLI_path_join(osx_resourses, sizeof(osx_resourses), g_app.program_dirname, "..", "Resources");
   /* Remove the '/../' added above. */
   BLI_path_normalize(NULL, osx_resourses);
   path_base = osx_resourses;
@@ -525,7 +528,9 @@ static bool get_path_system_ex(char *targetpath,
   char relfolder[FILE_MAX];
 
   if (folder_name) { /* `subfolder_name` may be NULL. */
-    BLI_path_join(relfolder, sizeof(relfolder), folder_name, subfolder_name, NULL);
+    const char *path_array[] = {folder_name, subfolder_name};
+    const int path_array_num = subfolder_name ? 2 : 1;
+    BLI_path_join_array(relfolder, sizeof(relfolder), path_array, path_array_num);
   }
   else {
     relfolder[0] = '\0';
@@ -1041,8 +1046,7 @@ bool BKE_appdir_app_template_has_userpref(const char *app_template)
   }
 
   char userpref_path[FILE_MAX];
-  BLI_path_join(
-      userpref_path, sizeof(userpref_path), app_template_path, BLENDER_USERPREF_FILE, NULL);
+  BLI_path_join(userpref_path, sizeof(userpref_path), app_template_path, BLENDER_USERPREF_FILE);
   return BLI_exists(userpref_path);
 }
 
diff --git a/source/blender/blenkernel/intern/asset_catalog.cc b/source/blender/blenkernel/intern/asset_catalog.cc
index f7b14cc3479..cedb0d8b4bf 100644
--- a/source/blender/blenkernel/intern/asset_catalog.cc
+++ b/source/blender/blenkernel/intern/asset_catalog.cc
@@ -515,8 +515,7 @@ CatalogFilePath AssetCatalogService::find_suitable_cdf_path_for_writing(
     BLI_path_join(asset_lib_cdf_path,
                   sizeof(asset_lib_cdf_path),
                   suitable_root_path,
-                  DEFAULT_CATALOG_FILENAME.c_str(),
-                  nullptr);
+                  DEFAULT_CATALOG_FILENAME.c_str());
     return asset_lib_cdf_path;
   }
 
diff --git a/source/blender/blenkernel/intern/blendfile.c b/source/blender/blenkernel/intern/blendfile.c
index 6546659f6cd..85a43b7c479 100644
--- a/source/blender/blenkernel/intern/blendfile.c
+++ b/source/blender/blenkernel/intern/blendfile.c
@@ -737,7 +737,7 @@ bool BKE_blendfile_userdef_write_all(ReportList *reports)
 
   if ((cfgdir = BKE_appdir_folder_id_create(BLENDER_USER_CONFIG, NULL))) {
     bool ok_write;
-    BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_USERPREF_FILE, NULL);
+    BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_USERPREF_FILE);
 
     printf("Writing userprefs: '%s' ", filepath);
     if (use_template_userpref) {
@@ -764,7 +764,7 @@ bool BKE_blendfile_userdef_write_all(ReportList *reports)
   if (use_template_userpref) {
     if ((cfgdir = BKE_appdir_folder_id_create(BLENDER_USER_CONFIG, U.app_template))) {
       /* Also save app-template prefs */
-      BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_USERPREF_FILE, NULL);
+      BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_USERPREF_FILE);
 
       printf("Writing userprefs app-template: '%s' ", filepath);
       if (BKE_blendfile_userdef_write(filepath, reports) != 0) {
diff --git a/source/blender/blenkernel/intern/fluid.c b/source/blender/blenkernel/intern/fluid.c
index 0a39207184a..5470231cd07 100644
--- a/source/blender/blenkernel/intern/fluid.c
+++ b/source/blender/blenkernel/intern/fluid.c
@@ -327,17 +327,17 @@ void BKE_fluid_cache_free(FluidDomainSettings *fds, Object *ob, int cache_map)
 
   if (cache_map & FLUID_DOMAIN_OUTDATED_DATA) {
     flags &= ~(FLUID_DOMAIN_BAKING_DATA | FLUID_DOMAIN_BAKED_DATA | FLUID_DOMAIN_OUTDATED_DATA);
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_CONFIG, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_CONFIG);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
     }
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_DATA, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_DATA);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
     }
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
@@ -346,7 +346,7 @@ void BKE_fluid_cache_free(FluidDomainSettings *fds, Object *ob, int cache_map)
   }
   if (cache_map & FLUID_DOMAIN_OUTDATED_NOISE) {
     flags &= ~(FLUID_DOMAIN_BAKING_NOISE | FLUID_DOMAIN_BAKED_NOISE | FLUID_DOMAIN_OUTDATED_NOISE);
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
@@ -355,7 +355,7 @@ void BKE_fluid_cache_free(FluidDomainSettings *fds, Object *ob, int cache_map)
   }
   if (cache_map & FLUID_DOMAIN_OUTDATED_MESH) {
     flags &= ~(FLUID_DOMAIN_BAKING_MESH | FLUID_DOMAIN_BAKED_MESH | FLUID_DOMAIN_OUTDATED_MESH);
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_MESH, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_MESH);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
@@ -365,8 +365,7 @@ void BKE_fluid_cache_free(FluidDomainSettings *fds, Object *ob, int cache_map)
   if (cache_map & FLUID_DOMAIN_OUTDATED_PARTICLES) {
     flags &= ~(FLUID_DOMAIN_BAKING_PARTICLES | FLUID_DOMAIN_BAKED_PARTICLES |
                FLUID_DOMAIN_OUTDATED_PARTICLES);
-    BLI_path_join(
-        temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_PARTICLES, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_PARTICLES);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
@@ -375,7 +374,7 @@ void BKE_fluid_cache_free(FluidDomainSettings *fds, Object *ob, int cache_map)
   }
   if (cache_map & FLUID_DOMAIN_OUTDATED_GUIDE) {
     flags &= ~(FLUID_DOMAIN_BAKING_GUIDE | FLUID_DOMAIN_BAKED_GUIDE | FLUID_DOMAIN_OUTDATED_GUIDE);
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE);
     BLI_path_abs(temp_dir, relbase);
     if (BLI_exists(temp_dir)) {
       BLI_delete(temp_dir, true, true);
diff --git a/source/blender/blenkernel/intern/image_save.cc b/source/blender/blenkernel/intern/image_save.cc
index e227f9cba5e..4e47e71fb2b 100644
--- a/source/blender/blenkernel/intern/image_save.cc
+++ b/source/blender/blenkernel/intern/image_save.cc
@@ -175,12 +175,12 @@ bool BKE_image_save_options_init(ImageSaveOptions *opts,
           BLI_strncpy(opts->filepath, G.ima, sizeof(opts->filepath));
         }
         else {
-          BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", DATA_("untitled"), nullptr);
+          BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", DATA_("untitled"));
           BLI_path_abs(opts->filepath, BKE_main_blendfile_path(bmain));
         }
       }
       else {
-        BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", ima->id.name + 2, nullptr);
+        BLI_path_join(opts->filepath, sizeof(opts->filepath), "//", ima->id.name + 2);
         BLI_path_make_safe(opts->filepath);
         BLI_path_abs(opts->filepath, is_prev_save ? G.ima : BKE_main_blendfile_path(bmain));
       }
diff --git a/source/blender/blenkernel/intern/packedFile.c b/source/blender/blenkernel/intern/packedFile.c
index 901b42ac0b2..0c9d9f5b048 100644
--- a/source/blender/blenkernel/intern/packedFile.c
+++ b/source/blender/blenkernel/intern/packedFile.c
@@ -545,7 +545,7 @@ static void unpack_generate_paths(const char *name,
         break;
     }
     if (dir_name) {
-      BLI_path_join(r_relpath, relpathlen, "//", dir_name, tempname, NULL);
+      BLI_path_join(r_relpath, relpathlen, "//", dir_name, tempname);
     }
   }
 
diff --git a/source/blender/blenkernel/intern/preferences.c b/source/blender/blenkernel/intern/preferences.c
index b2e795901fb..dd76f9eddc1 100644
--- a/source/blender/blenkernel/intern/preferences.c
+++ b/source/blender/blenkernel/intern/preferences.c
@@ -115,8 +115,7 @@ void BKE_preferences_asset_library_default_add(UserDef *userdef)
       userdef, DATA_(BKE_PREFS_ASSET_LIBRARY_DEFAULT_NAME), NULL);
 
   /* Add new "Default" library under '[doc_path]/Blender/Assets'. */
-  BLI_path_join(
-      library->path, sizeof(library->path), documents_path, N_("Blender"), N_("Assets"), NULL);
+  BLI_path_join(library->path, sizeof(library->path), documents_path, N_("Blender"), N_("Assets"));
 }
 
 /** \} */
diff --git a/source/blender/blenlib/BLI_path_util.h b/source/blender/blenlib/BLI_path_util.h
index 1e45e76afe1..739b894eafe 100644
--- a/source/blender/blenlib/BLI_path_util.h
+++ b/source/blender/blenlib/BLI_path_util.h
@@ -7,7 +7,9 @@
  */
 
 #include "BLI_compiler_attrs.h"
+#include "BLI_compiler_compat.h"
 #include "BLI_utildefines.h"
+#include "BLI_utildefines_variadic.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -81,6 +83,14 @@ void BLI_join_dirfile(char *__restrict dst,
                       const char *__restrict dir,
                       const char *__restrict file) ATTR_NONNULL();
 /**
+ * See #BLI_path_join doc-string.
+ */
+size_t BLI_path_join_array(char *__restrict dst,
+                           const size_t dst_len,
+                           const char *path_array[],
+                           const int path_array_num);
+
+/**
  * Join multiple strings into a path, ensuring only a single path separator between each,
  * and trailing slash is kept.
  *
@@ -95,8 +105,94 @@ void BLI_join_dirfile(char *__restrict dst,
  * \note If you want a trailing slash, add `SEP_STR` as the last path argument,
  * duplicate slashes will be cleaned up.
  */
-size_t BLI_path_join(char *__restrict dst, size_t dst_len, const char *path, ...)
-    ATTR_NONNULL(1, 3) ATTR_SENTINEL(0);
+#define BLI_path_join(...) VA_NARGS_CALL_OVERLOAD(_BLI_path_join_, __VA_ARGS__)
+
+#define _BLI_PATH_JOIN_ARGS_1 char *__restrict dst, size_t dst_len, const char *a
+#define _BLI_PATH_JOIN_ARGS_2 _BLI_PATH_JOIN_ARGS_1, const char *b
+#define _BLI_PATH_JOIN_ARGS_3 _BLI_PATH_JOIN_ARGS_2, const char *c
+#define _BLI_PATH_JOIN_ARGS_4 _BLI_PATH_JOIN_ARGS_3, const char *d
+#define _BLI_PATH_JOIN_ARGS_5 _BLI_PATH_JOIN_ARGS_4, const char *e
+#define _BLI_PATH_JOIN_ARGS_6 _BLI_PATH_JOIN_ARGS_5, const char *f
+#define _BLI_PATH_JOIN_ARGS_7 _BLI_PATH_JOIN_ARGS_6, const char *g
+#define _BLI_PATH_JOIN_ARGS_8 _BLI_PATH_JOIN_ARGS_7, const char *h
+#define _BLI_PATH_JOIN_ARGS_9 _BLI_PATH_JOIN_ARGS_8, const char *i
+#define _BLI_PATH_JOIN_ARGS_10 _BLI_PATH_JOIN_ARGS_9, const char *j
+#define _BLI_PATH_JOIN_ARGS_11 _BLI_PATH_JOIN_ARGS_10, const char *k
+
+BLI_INLINE size_t _BLI_path_join_3(_BLI_PATH_JOIN_ARGS_1) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_4(_BLI_PATH_JOIN_ARGS_2) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_5(_BLI_PATH_JOIN_ARGS_3) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_6(_BLI_PATH_JOIN_ARGS_4) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_7(_BLI_PATH_JOIN_ARGS_5) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_8(_BLI_PATH_JOIN_ARGS_6) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_9(_BLI_PATH_JOIN_ARGS_7) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_10(_BLI_PATH_JOIN_ARGS_8) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_11(_BLI_PATH_JOIN_ARGS_9) ATTR_NONNULL();
+BLI_INLINE size_t _BLI_path_join_12(_BLI_PATH_JOIN_ARGS_10) ATTR_NONNULL();
+
+BLI_INLINE size_t _BLI_path_join_3(_BLI_PATH_JOIN_ARGS_1)
+{
+  const char *path_array[] = {a};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_4(_BLI_PATH_JOIN_ARGS_2)
+{
+  const char *path_array[] = {a, b};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_5(_BLI_PATH_JOIN_ARGS_3)
+{
+  const char *path_array[] = {a, b, c};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_6(_BLI_PATH_JOIN_ARGS_4)
+{
+  const char *path_array[] = {a, b, c, d};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_7(_BLI_PATH_JOIN_ARGS_5)
+{
+  const char *path_array[] = {a, b, c, d, e};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_8(_BLI_PATH_JOIN_ARGS_6)
+{
+  const char *path_array[] = {a, b, c, d, e, f};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_9(_BLI_PATH_JOIN_ARGS_7)
+{
+  const char *path_array[] = {a, b, c, d, e, f, g};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_10(_BLI_PATH_JOIN_ARGS_8)
+{
+  const char *path_array[] = {a, b, c, d, e, f, g, h};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_11(_BLI_PATH_JOIN_ARGS_9)
+{
+  const char *path_array[] = {a, b, c, d, e, f, g, h, i};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+BLI_INLINE size_t _BLI_path_join_12(_BLI_PATH_JOIN_ARGS_10)
+{
+  const char *path_array[] = {a, b, c, d, e, f, g, h, i, j};
+  return BLI_path_join_array(dst, dst_len, path_array, ARRAY_SIZE(path_array));
+}
+
+#undef _BLI_PATH_JOIN_ARGS_1
+#undef _BLI_PATH_JOIN_ARGS_2
+#undef _BLI_PATH_JOIN_ARGS_3
+#undef _BLI_PATH_JOIN_ARGS_4
+#undef _BLI_PATH_JOIN_ARGS_5
+#undef _BLI_PATH_JOIN_ARGS_6
+#undef _BLI_PATH_JOIN_ARGS_7
+#undef _BLI_PATH_JOIN_ARGS_8
+#undef _BLI_PATH_JOIN_ARGS_9
+#undef _BLI_PATH_JOIN_ARGS_10
+#undef _BLI_PATH_JOIN_ARGS_11
+
 /**
  * Like Python's `os.path.basename()`
  *
diff --git a/source/blender/blenlib/intern/path_util.c b/source/blender/blenlib/intern/path_util.c
index 6ff4d57aecb..0a6e39504df 100644
--- a/source/blender/blenlib/intern/path_util.c
+++ b/source/blender/blenlib/intern/path_util.c
@@ -1490,14 +1490,20 @@ void BLI_join_dirfile(char *__restrict dst,
   BLI_strncpy(dst + dirlen, file, maxlen - dirlen);
 }
 
-size_t BLI_path_join(char *__restrict dst, const size_t dst_len, const char *path, ...)
+size_t BLI_path_join_array(char *__restrict dst,
+                           const size_t dst_len,
+                           const char *path_array[],
+                           const int path_array_num)
 {
+  BLI_assert(path_array_num > 0);
 #ifdef DEBUG_STRSIZE
   memset(dst, 0xff, sizeof(*dst) * dst_len);
 #endif
   if (UNLIKELY(dst_len == 0)) {
     return 0;
   }
+  const char *path = path_array[0];
+
   const size_t dst_last = dst_len - 1;
   size_t ofs = BLI_strncpy_rlen(dst, path, dst_len);
 
@@ -1519,9 +1525,8 @@ size_t BLI_path_join(char *__restrict dst, const size_t dst_len, const char *pat
     has_trailing_slash = (path[len] != '\0');
   }
 
-  va_list args;
-  va_start(args, path);
-  while ((path = (const char *)va_arg(args, const char *))) {
+  for (int path_index = 1; path_index < path_array_num; path_index++) {
+    path = path_array[path_index];
     has_trailing_slash = false;
     const char *path_init = path;
     while (ELEM(path[0], SEP, ALTSEP)) {
@@ -1556,7 +1561,6 @@ size_t BLI_path_join(char *__restrict dst, const size_t dst_len, const char *pat
       has_trailing_slash = (path_init != path);
     }
   }
-  va_end(args);
 
   if (has_trailing_slash) {
     if ((ofs != dst_last) && (ofs != 0) && (ELEM(dst[ofs - 1], SEP, ALTSEP) == 0)) {
diff --git a/source/blender/blenlib/tests/BLI_path_util_test.cc b/source/blender/blenlib/tests/BLI_path_util_test.cc
index 2d415534693..89e537235db 100644
--- a/source/blender/blenlib/tests/BLI_path_util_test.cc
+++ b/source/blender/blenlib/tests/BLI_path_util_test.cc
@@ -207,7 +207,7 @@ TEST(path_util, NameAtIndex_NoneComplexNeg)
     char result[(out_size) + 1024]; \
     /* check we don't write past the last byte */ \
     result[out_size] = '\0'; \
-    BLI_path_join(result, out_size, __VA_ARGS__, NULL); \
+    BLI_path_join(result, out_size, __VA_ARGS__); \
     /* simplify expected string */ \
     BLI_str_replace_char(result, '\\', '/'); \
     EXPECT_STREQ(result, expect); \
diff --git a/source/blender/blenloader/tests/blendfile_loading_base_test.cc b/source/blender/blenloader/tests/blendfile_loading_base_test.cc
index 615e30a728e..b657970d45f 100644
--- a/source/blender/blenloader/tests/blendfile_loading_base_test.cc
+++ b/source/blender/blenloader/tests/blendfile_loading_base_test.cc
@@ -117,7 +117,7 @@ bool BlendfileLoadingBaseTest::blendfile_load(const char *filepath)
   }
 
   char abspath[FILENAME_MAX];
-  BLI_path_join(abspath, sizeof(abspath), test_assets_dir.c_str(), filepath, nullptr);
+  BLI_path_join(abspath, sizeof(abspath), test_assets_dir.c_str(), filepath);
 
   BlendFileReadReport bf_reports = {nullptr};
   bfile = BLO_read_from_file(abspath, BLO_READ_SKIP_NONE, &bf_reports);
diff --git a/source/blender/editors/physics/physics_fluid.c b/source/blender/editors/physics/physics_fluid.c
index 07e8f5c5743..314796e96e4 100644
--- a/source/blender/editors/physics/physics_fluid.c
+++ b/source/blender/editors/physics/physics_fluid.c
@@ -368,7 +368,7 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
   BKE_spacedata_draw_locks(true);
 
   if (fluid_is_bake_noise(job) || fluid_is_bake_all(job)) {
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_NOISE);
     BLI_path_abs(temp_dir, relbase);
     BLI_dir_create_recursive(temp_dir); /* Create 'noise' subdir if it does not exist already */
     fds->cache_flag &= ~(FLUID_DOMAIN_BAKED_NOISE | FLUID_DOMAIN_OUTDATED_NOISE);
@@ -376,7 +376,7 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
     job->pause_frame = &fds->cache_frame_pause_noise;
   }
   if (fluid_is_bake_mesh(job) || fluid_is_bake_all(job)) {
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_MESH, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_MESH);
     BLI_path_abs(temp_dir, relbase);
     BLI_dir_create_recursive(temp_dir); /* Create 'mesh' subdir if it does not exist already */
     fds->cache_flag &= ~(FLUID_DOMAIN_BAKED_MESH | FLUID_DOMAIN_OUTDATED_MESH);
@@ -384,8 +384,7 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
     job->pause_frame = &fds->cache_frame_pause_mesh;
   }
   if (fluid_is_bake_particle(job) || fluid_is_bake_all(job)) {
-    BLI_path_join(
-        temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_PARTICLES, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_PARTICLES);
     BLI_path_abs(temp_dir, relbase);
 
     /* Create 'particles' subdir if it does not exist already */
@@ -396,7 +395,7 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
     job->pause_frame = &fds->cache_frame_pause_particles;
   }
   if (fluid_is_bake_guiding(job) || fluid_is_bake_all(job)) {
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_GUIDE);
     BLI_path_abs(temp_dir, relbase);
     BLI_dir_create_recursive(temp_dir); /* Create 'guiding' subdir if it does not exist already */
     fds->cache_flag &= ~(FLUID_DOMAIN_BAKED_GUIDE | FLUID_DOMAIN_OUTDATED_GUIDE);
@@ -404,11 +403,11 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
     job->pause_frame = &fds->cache_frame_pause_guide;
   }
   if (fluid_is_bake_data(job) || fluid_is_bake_all(job)) {
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_CONFIG, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_CONFIG);
     BLI_path_abs(temp_dir, relbase);
     BLI_dir_create_recursive(temp_dir); /* Create 'config' subdir if it does not exist already */
 
-    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_DATA, NULL);
+    BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_DATA);
     BLI_path_abs(temp_dir, relbase);
     BLI_dir_create_recursive(temp_dir); /* Create 'data' subdir if it does not exist already */
     fds->cache_flag &= ~(FLUID_DOMAIN_BAKED_DATA | FLUID_DOMAIN_OUTDATED_DATA);
@@ -416,8 +415,7 @@ static void fluid_bake_startjob(void *customdata, short *stop, short *do_update,
     job->pause_frame = &fds->cache_frame_pause_data;
 
     if (fds->flags & FLUID_DOMAIN_EXPORT_MANTA_SCRIPT) {
-      BLI_path_join(
-          temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT, NULL);
+      BLI_path_join(temp_dir, sizeof(temp_dir), fds->cache_directory, FLUID_DOMAIN_DIR_SCRIPT);
       BLI_path_abs(temp_dir, relbase);
       BLI_dir_create_recursive(temp_dir); /* Create 'script' subdir if it does not exist already */
     }
diff --git a/source/blender/editors/space_file/file_ops.c b/source/blender/editors/space_file/file_ops.c
index f7fd910d6e9..63aa71e9855 100644
--- a/source/blender/editors/space_file/file_ops.c
+++ b/source/blender/editors/space_file/file_ops.c
@@ -2457,8 +2457,7 @@ static void file_expand_directory(bContext *C)
     else if (params->dir[0] == '~') {
       char tmpstr[sizeof(params->dir) - 1];
       BLI_strncpy(tmpstr, params->dir + 1, sizeof(tmpstr));
-      BLI_path_join(
-          params->dir, sizeof(params->dir), BKE_appdir_folder_default_or_root(), tmpstr, NULL);
+      BLI_path_join(params->dir, sizeof(params->dir), BKE_appdir_folder_default_or_root(), tmpstr);
     }
 
     else if (params->dir[0] == '\0')
diff --git a/source/blender/editors/space_file/fsmenu.c b/source/blender/editors/space_file/fsmenu.c
index 35ce7ef364c..a6c5e0f1734 100644
--- a/source/blender/editors/space_file/fsmenu.c
+++ b/source/blender/editors/space_file/fsmenu.c
@@ -113,10 +113,10 @@ static GHash *fsmenu_xdg_user_dirs_parse(const char *home)
     char filepath[FILE_MAX];
     const char *xdg_config_home = getenv("XDG_CONFIG_HOME");
     if (xdg_config_home != NULL) {
-      BLI_path_join(filepath, sizeof(filepath), xdg_config_home, "user-dirs.dirs", NULL);
+      BLI_path_join(filepath, sizeof(filepath), xdg_config_home, "user-dirs.dirs");
     }
     else {
-      BLI_path_join(filepath, sizeof(filepath), home, ".config", "user-dirs.dirs", NULL);
+      BLI_path_join(filepath, sizeof(filepath), home, ".config", "user-dirs.dirs");
     }
     fp = BLI_fopen(filepath, "r");
     if (!fp) {
@@ -147,7 +147,7 @@ static GHash *fsmenu_xdg_user_dirs_parse(const char *home)
            * Based on the 'user-dirs.dirs' man page,
            * there is no need to resolve arbitrary environment variables. */
           if (STRPREFIX(l_value, "$HOME" SEP_STR)) {
-            BLI_path_join(l_value_expanded, sizeof(l_value_expanded), home, l_value + 6, NULL);
+            BLI_path_join(l_value_expanded, sizeof(l_value_expanded), home, l_value + 6);
             l_value_final = l_value_expanded;
           }
 
@@ -186,7 +186,7 @@ static void fsmenu_xdg_insert_entry(GHash *xdg_map,
   char xdg_path_buf[FILE_MAXDIR];
   const char *xdg_path = xdg_map ? BLI_ghash_lookup(xdg_map, key) : NULL;
   if (xdg_path == NULL) {
-    BLI_path_join(xdg_path_buf, sizeof(xdg_path_buf), home, default_path, NULL);
+    BLI_path_join(xdg_path_buf, sizeof(xdg_path_buf), home, default_path);
     xdg_path = xdg_path_buf;
   }
   fsmenu_insert_entry(
diff --git a/source/blender/editors/util/ed_util.c b/source/blender/editors/util/ed_util.c
index 12e77c6ef00..92d65688bf1 100644
--- a/source/blender/editors/util/ed_util.c
+++ b/source/blender/editors/util/ed_util.c
@@ -374,7 +374,7 @@ void unpack_menu(bContext *C,
     char local_name[FILE_MAXDIR + FILE_MAX], fi[FILE_MAX];
 
     BLI_split_file_part(abs_name, fi, sizeof(fi));
-    BLI_path_join(local_name, sizeof(local_name), "//", folder, fi, NULL);
+    BLI_path_join(local_name, sizeof(local_name), "//", folder, fi);
     if (!STREQ(abs_name, local_name)) {
       switch (BKE_packedfile_compare_to_file(blendfile_path, local_name, pf)) {
         case PF_CMP_NOFILE:
diff --git a/source/blender/io/common/intern/path_util.cc b/source/blender/io/common/intern/path_util.cc
index 18632b410f8..63ff6cf29ee 100644
--- a/source/blender/io/common/intern/path_util.cc
+++ b/source/blender/io/common/intern/path_util.cc
@@ -28,8 +28,7 @@ std::string path_reference(StringRefNull filepath,
   }
   else if (mode == PATH_REFERENCE_COPY) {
     char filepath_cpy[PATH_MAX];
-    BLI_path_join(
-        filepath_cpy, PATH_MAX, base_dst.c_str(), BLI_path_basename(filepath_abs), nullptr);
+    BLI_path_join(filepath_cpy, PATH_MAX, base_dst.c_str(), BLI_path_basename(filepath_abs));
     copy_set->add(std::make_pair(filepath_abs, filepath_cpy));
     BLI_strncpy(filepath_abs, filepath_cpy, PATH_MAX);
     mode = PATH_REFERENCE_RELATIVE;
diff --git a/source/blender/io/usd/intern/usd_writer_material.cc b/source/blender/io/usd/intern/usd_writer_material.cc
index c195bf0e0bd..75abae79519 100644
--- a/source/blender/io/usd/intern/usd_writer_material.cc
+++ b/source/blender/io/usd/intern/usd_writer_material.cc
@@ -380,7 +380,7 @@ static void export_in_memory_texture(Image *ima,
   BKE_image_path_ensure_ext_from_imformat(file_name, &imageFormat);
 
   char export_path[FILE_MAX];
-  BLI_path_join(export_path, FILE_MAX, export_dir.c_str(), file_name, nullptr);
+  BLI_path_join(export_path, FILE_MAX, export_dir.c_str(), file_name);
 
   if (!allow_overwrite && BLI_exists(export_path)) {
     return;
@@ -576,7 +576,7 @@ static std::string get_tex_image_asset_path(bNode *node,
     BLI_split_file_part(path.c_str(), file_path, FILE_MAX);
 
     if (export_params.relative_paths) {
-      BLI_path_join(exp_path, FILE_MAX, ".", "textures", file_path, nullptr);
+      BLI_path_join(exp_path, FILE_MAX, ".", "textures", file_path);
     }
     else {
       /* Create absolute path in the textures directory. */
@@ -588,7 +588,7 @@ static std::string get_tex_image_asset_path(bNode *node,
 
       char dir_path[FILE_MAX];
       BLI_split_dir_part(stage_path.c_str(), dir_path, FILE_MAX);
-      BLI_path_join(exp_path, FILE_MAX, dir_path, "textures", file_path, nullptr);
+      BLI_path_join(exp_path, FILE_MAX, dir_path, "textures", file_path);
     }
     BLI_str_replace_char(exp_path, '\\', '/');
     return exp_path;
@@ -645,7 +645,7 @@ static void copy_tiled_textures(Image *ima,
     BLI_split_file_part(src_tile_path, dest_filename, sizeof(dest_filename));
 
     char dest_tile_path[FILE_MAX];
-    BLI_path_join(dest_tile_path, FILE_MAX, dest_dir.c_str(), dest_filename, nullptr);
+    BLI_path_join(dest_tile_path, FILE_MAX, dest_dir.c_str(), dest_filename);
 
     if (!allow_overwrite && BLI_exists(dest_tile_path)) {
       continue;
@@ -680,7 +680,7 @@ static void copy_single_file(Image *ima, const std::string &dest_dir, const bool
   BLI_split_file_part(source_path, file_name, FILE_MAX);
 
   char dest_path[FILE_MAX];
-  BLI_path_join(dest_path, FILE_MAX, dest_dir.c_str(), file_name, nullptr);
+  BLI_path_join(dest_path, FILE_MAX, dest_dir.c_str(), file_name);
 
   if (!allow_overwrite && BLI_exists(dest_path)) {
     return;
@@ -726,7 +726,7 @@ static void export_texture(bNode *node,
   BLI_split_dir_part(stage_path.c_str(), usd_dir_path, FILE_MAX);
 
   char tex_dir_path[FILE_MAX];
-  BLI_path_join(tex_dir_path, FILE_MAX, usd_dir_path, "textures", SEP_STR, nullptr);
+  BLI_path_join(tex_dir_path, FILE_MAX, usd_dir_path, "textures", SEP_STR);
 
   BLI_dir_create_recursive(tex_dir_path);
 
diff --git a/source/blender/io/usd/intern/usd_writer_volume.cc b/source/blender/io/usd/intern/usd_writer_volume.cc
index 8cc3c65ee70..c6a27c5f663 100644
--- a/source/blender/io/usd/intern/usd_writer_volume.cc
+++ b/source/blender/io/usd/intern/usd_writer_volume.cc
@@ -152,7 +152,7 @@ std::optional<std::string> USDVolumeWriter::construct_vdb_file_path(const Volume
   strcat(vdb_file_name, ".vdb");
 
   char vdb_file_path[FILE_MAX];
-  BLI_path_join(vdb_file_path, sizeof(vdb_file_path), vdb_directory_path, vdb_file_name, nullptr);
+  BLI_path_join(vdb_file_path, sizeof(vdb_file_path), vdb_directory_path, vdb_file_name);
 
   return vdb_file_path;
 }
diff --git a/source/blender/io/usd/tests/usd_tests_common.cc b/source/blender/io/usd/tests/usd_tests_common.cc
index 9f18a289433..ea4e704006d 100644
--- a/source/blender/io/usd/tests/usd_tests_common.cc
+++ b/source/blender/io/usd/tests/usd_tests_common.cc
@@ -29,7 +29,7 @@ std::string register_usd_plugins_for_tests()
   }
 
   const size_t path_len = BLI_path_join(
-      usd_datafiles_dir, FILE_MAX, release_dir.c_str(), "datafiles", "usd", nullptr);
+      usd_datafiles_dir, FILE_MAX, release_dir.c_str(), "datafiles", "usd");
 
   /* #BLI_path_join removes trailing slashes, but the USD library requires one in order to
    * recognize the path as directory. */
diff --git a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
index 0781028c880..7d5f023af4b 100644
--- a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
+++ b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc
@@ -765,7 +765,7 @@ MTLParser::MTLParser(StringRefNull mtl_library, StringRefNull obj_filepath)
 {
   char obj_file_dir[FILE_MAXDIR];
   BLI_split_dir_part(obj_filepath.data(), obj_file_dir, FILE_MAXDIR);
-  BLI_path_join(mtl_file_path_, FILE_MAX, obj_file_dir, mtl_library.data(), nullptr);
+  BLI_path_join(mtl_file_path_, FILE_MAX, obj_file_dir, mtl_library.data());
   BLI_split_dir_part(mtl_file_path_, mtl_dir_path_, FILE_MAXDIR);
 }
 
diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index 7ac55b2c27a..a3593a33bae 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -1166,12 +1166,10 @@ void wm_homefile_read_ex(bContext *C,
   const char *const cfgdir = BKE_appdir_folder_id(BLENDER_USER_CONFIG, NULL);
   if (!use_factory_settings) {
     if (cfgdir) {
-      BLI_path_join(
-          filepath_startup, sizeof(filepath_startup), cfgdir, BLENDER_STARTUP_FILE, NULL);
+      BLI_path_join(filepath_startup, sizeof(filepath_startup), cfgdir, BLENDER_STARTUP_FILE);
       filepath_startup_is_factory = false;
       if (use_userdef) {
-        BLI_path_join(
-            filepath_userdef, sizeof(filepath_startup), cfgdir, BLENDER_USERPREF_FILE, NULL);
+        BLI_path_join(filepath_userdef, sizeof(filepath_startup), cfgdir, BLENDER_USERPREF_FILE);
       }
     }
     else {
@@ -1214,12 +1212,9 @@ void wm_homefile_read_ex(bContext *C,
     /* note that the path is being set even when 'use_factory_settings == true'
      * this is done so we can load a templates factory-settings */
     if (!use_factory_settings) {
-      BLI_path_join(app_template_config, sizeof(app_template_config), cfgdir, app_template, NULL);
-      BLI_path_join(filepath_startup,
-                    sizeof(filepath_startup),
-                    app_template_config,
-                    BLENDER_STARTUP_FILE,
-                    NULL);
+      BLI_path_join(app_template_config, sizeof(app_template_config), cfgdir, app_template);
+      BLI_path_join(
+          filepath_startup, sizeof(filepath_startup), app_template_config, BLENDER_STARTUP_FILE);
       filepath_startup_is_factory = false;
       if (BLI_access(filepath_startup, R_OK) != 0) {
         filepath_startup[0] = '\0';
@@ -1230,11 +1225,8 @@ void wm_homefile_read_ex(bContext *C,
     }
 
     if (filepath_startup[0] == '\0') {
-      BLI_path_join(filepath_startup,
-                    sizeof(filepath_startup),
-                    app_template_system,
-                    BLENDER_STARTUP_FILE,
-                    NULL);
+      BLI_path_join(
+          filepath_startup, sizeof(filepath_startup), app_template_system, BLENDER_STARTUP_FILE);
       filepath_startup_is_factory = true;
 
       /* Update defaults only for system templates. */
@@ -1303,16 +1295,14 @@ void wm_homefile_read_ex(bContext *C,
     char temp_path[FILE_MAX];
     temp_path[0] = '\0';
     if (!use_factory_settings) {
-      BLI_path_join(
-          temp_path, sizeof(temp_path), app_template_config, BLENDER_USERPREF_FILE, NULL);
+      BLI_path_join(temp_path, sizeof(temp_path), app_template_config, BLENDER_USERPREF_FILE);
       if (BLI_access(temp_path, R_OK) != 0) {
         temp_path[0] = '\0';
       }
     }
 
     if (temp_path[0] == '\0') {
-      BLI_path_join(
-          temp_path, sizeof(temp_path), app_template_system, BLENDER_USERPREF_FILE, NULL);
+      BLI_path_join(temp_path, sizeof(temp_path), app_template_system, BLENDER_USERPREF_FILE);
     }
 
     if (use_userdef) {
@@ -2132,7 +2122,7 @@ static int wm_homefile_write_exec(bContext *C, wmOperator *op)
   /* update keymaps in user preferences */
   WM_keyconfig_update(wm);
 
-  BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_STARTUP_FILE, NULL);
+  BLI_path_join(filepath, sizeof(filepath), cfgdir, BLENDER_STARTUP_FILE);
 
   printf("Writing homefile: '%s' ", filepath);
 
diff --git a/source/blender/windowmanager/intern/wm_splash_screen.c b/source/blender/windowmanager/intern/wm_splash_screen.c
index 8fca3deef92..48325b28f5a 100644
--- a/source/blender/windowmanager/intern/wm_splash_screen.c
+++ b/source/blender/windowmanager/intern/wm_splash_screen.c
@@ -218,7 +218,7 @@ static uiBlock *wm_block_create_splash(bContext *C, ARegion *region, void *UNUSE
   const char *const cfgdir = BKE_appdir_folder_id(BLENDER_USER_CONFIG, NULL);
 
   if (cfgdir) {
-    BLI_path_join(userpref, sizeof(userpref), cfgdir, BLENDER_USERPREF_FILE, NULL);
+    BLI_path_join(userpref, sizeof(userpref), cfgdir, BLENDER_USERPREF_FILE);
   }
 
   /* Draw setup screen if no preferences have been saved yet. */