Fix T87489: Text Data-Blocks get deleted on Recursive Purge

Text data block were not considered special in the recursive purge
function.  So they would get deleted if they had no actual users.

To fix this we instead make text data block use "fake user" so that
addon authors can specify script files that should be removed if nothing
is using it anymore.

Per default, new text object have "fake user" set. So functionality
wise, the user has to explicitly specify that they want the text object
to be purge-able.

Reviewed By: Bastien

Differential Revision: http://developer.blender.org/D10983

3 files changed, 35 insertions, 15 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index b4623425582..24501adcb90 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -2912,7 +2912,7 @@ static void lib_link_workspace_layout_restore(struct IDNameLib_Map *id_map,
         else if (sl->spacetype == SPACE_TEXT) {
           SpaceText *st = (SpaceText *)sl;
 
-          st->text = restore_pointer_by_name(id_map, (ID *)st->text, USER_REAL);
+          st->text = restore_pointer_by_name(id_map, (ID *)st->text, USER_IGNORE);
           if (st->text == NULL) {
             st->text = newmain->texts.first;
           }
diff --git a/source/blender/blenloader/intern/versioning_290.c b/source/blender/blenloader/intern/versioning_290.c
index 916c4bf0cad..2b6f44c694b 100644
--- a/source/blender/blenloader/intern/versioning_290.c
+++ b/source/blender/blenloader/intern/versioning_290.c
@@ -48,6 +48,7 @@
 #include "DNA_screen_types.h"
 #include "DNA_shader_fx_types.h"
 #include "DNA_space_types.h"
+#include "DNA_text_types.h"
 #include "DNA_tracking_types.h"
 #include "DNA_workspace_types.h"
 
@@ -686,6 +687,15 @@ void do_versions_after_linking_290(Main *bmain, ReportList *UNUSED(reports))
     }
   }
 
+  if (!MAIN_VERSION_ATLEAST(bmain, 293, 20)) {
+    /* Set zero user text objects to have a fake user. */
+    LISTBASE_FOREACH (Text *, text, &bmain->texts) {
+      if (text->id.us == 0) {
+        id_fake_user_set(&text->id);
+      }
+    }
+  }
+
   /**
    * Versioning code until next subversion bump goes here.
    *
diff --git a/source/blender/blenloader/intern/versioning_300.c b/source/blender/blenloader/intern/versioning_300.c
index 6b13b21f057..ee38ad707a4 100644
--- a/source/blender/blenloader/intern/versioning_300.c
+++ b/source/blender/blenloader/intern/versioning_300.c
@@ -25,14 +25,24 @@
 
 #include "DNA_genfile.h"
 #include "DNA_modifier_types.h"
+#include "DNA_text_types.h"
 
+#include "BKE_lib_id.h"
 #include "BKE_main.h"
 
 #include "BLO_readfile.h"
 #include "readfile.h"
 
-void do_versions_after_linking_300(Main *UNUSED(bmain), ReportList *UNUSED(reports))
+void do_versions_after_linking_300(Main *bmain, ReportList *UNUSED(reports))
 {
+  if (MAIN_VERSION_ATLEAST(bmain, 300, 0) && !MAIN_VERSION_ATLEAST(bmain, 300, 1)) {
+    /* Set zero user text objects to have a fake user. */
+    LISTBASE_FOREACH (Text *, text, &bmain->texts) {
+      if (text->id.us == 0) {
+        id_fake_user_set(&text->id);
+      }
+    }
+  }
   /**
    * Versioning code until next subversion bump goes here.
    *
@@ -51,19 +61,7 @@ void do_versions_after_linking_300(Main *UNUSED(bmain), ReportList *UNUSED(repor
 /* NOLINTNEXTLINE: readability-function-size */
 void blo_do_versions_300(FileData *fd, Library *UNUSED(lib), Main *bmain)
 {
-
-  /**
-   * Versioning code until next subversion bump goes here.
-   *
-   * \note Be sure to check when bumping the version:
-   * - "versioning_userdef.c", #blo_do_versions_userdef
-   * - "versioning_userdef.c", #do_versions_theme
-   *
-   * \note Keep this message at the bottom of the function.
-   */
-  {
-    /* Keep this block, even when empty. */
-
+  if (!MAIN_VERSION_ATLEAST(bmain, 300, 1)) {
     /* Set default value for the new bisect_threshold parameter in the mirror modifier. */
     if (!DNA_struct_elem_find(fd->filesdna, "MirrorModifierData", "float", "bisect_threshold")) {
       LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
@@ -77,4 +75,16 @@ void blo_do_versions_300(FileData *fd, Library *UNUSED(lib), Main *bmain)
       }
     }
   }
+  /**
+   * Versioning code until next subversion bump goes here.
+   *
+   * \note Be sure to check when bumping the version:
+   * - "versioning_userdef.c", #blo_do_versions_userdef
+   * - "versioning_userdef.c", #do_versions_theme
+   *
+   * \note Keep this message at the bottom of the function.
+   */
+  {
+    /* Keep this block, even when empty. */
+  }
 }