Do not override library edit history from XMP sidecar file when using darktable-cli

src/cli/main.c

@@ -95,6 +95,8 @@ fprintf(stderr, "darktable %s\n"
                 "                          multiple times instead of input file\n"
                 "   --library <path> read the history stack from library database\n"
                 "                    instead of XMP sidecar files\n"
+                "                    using ':memory:' for an empty in-memory library\n"
+                "                    is useless for darktable cli export\n"
                 "   --icc-type <type> specify icc type, default to NONE\n"
                 "                     use --help icc-type for list of supported types\n"
                 "   --icc-file <file> specify icc filename, default to NONE\n"
@@ -384,6 +386,13 @@ int main(int argc, char *arg[])
       {
         k++;
         library = arg[k];
+        if(!strcmp(library, ":memory:"))
+        {
+          fprintf(stderr, _("empty in-memory library is useless for darktable cli export\n"));
+          usage(arg[0]);
+          exit(1);
+        }
+
       }
       else if(!strcmp(arg[k], "--icc-type") && argc > k + 1)
       {
@@ -575,6 +584,9 @@ int main(int argc, char *arg[])
     exit(1);
   }
 
+  // When --library was provided, use the DB history; otherwise keep XMP override mode.
+  darktable.prefer_library_history = (library != NULL);
+
   GList *id_list = NULL;
 
   for(GList *l = inputs; l != NULL; l=g_list_next(l))

src/common/darktable.h

@@ -486,6 +486,9 @@ typedef struct darktable_t
   int32_t unmuted_signal_dbg_acts;
   gboolean unmuted_signal_dbg[DT_SIGNAL_COUNT];
   gboolean pipe_cache;
+  // Keep database history for known images rather than replacing it from XMP.
+  // Set by darktable-cli with explicit --library <db>; GUI and CLI use XMP by default.
+  gboolean prefer_library_history;
   int gui_running;		// atomic, access with g_atomic_int_*()
   GTimeZone *utc_tz;
   GDateTime *origin_gdt;

src/common/image.c

@@ -1874,8 +1874,13 @@ static dt_imgid_t _image_import_internal(const dt_filmid_t film_id,
     if(img)
       img->flags &= ~DT_IMAGE_REMOVE;
     dt_image_cache_write_release(img, DT_IMAGE_CACHE_RELAXED);
-    _image_read_duplicates(id, normalized_filename, raise_signals);
-    dt_image_synch_all_xmp(normalized_filename);
+    // Reconcile with XMP sidecars unless library history is preferred to avoid
+    // overwriting library edit history with potentially stale XMP history.
+    if(!darktable.prefer_library_history)
+    {
+      _image_read_duplicates(id, normalized_filename, raise_signals);
+      dt_image_synch_all_xmp(normalized_filename);
+    }
     g_free(ext);
     g_free(normalized_filename);
     if(raise_signals)