Optionally import XMP files on copy & import

data/darktableconfig.xml.in

@@ -1164,6 +1164,13 @@
     <shortdescription>recursive directory</shortdescription>
     <longdescription>recursive directory traversal when importing filmrolls</longdescription>
   </dtconfig>
+  <dtconfig ui="yes">
+    <name>ui_last/import_copy_source_xmp</name>
+    <type>bool</type>
+    <default>false</default>
+    <shortdescription>import XMP sidecar files</shortdescription>
+    <longdescription>if XMP sidecar files are found next to the source images (darktable 'image.ext.xmp' or Lightroom 'image.xmp' naming), import their metadata - replacing any default import metadata - and write darktable XMP files alongside the copied images</longdescription>
+  </dtconfig>
   <dtconfig ui="yes">
     <name>ui_last/import_last_creator</name>
     <type>string</type>

src/control/jobs/control_jobs.c

@@ -2798,6 +2798,73 @@ void dt_control_write_sidecar_files()
                                           FALSE));
 }
 
+static void _import_copy_sidecar_file(const char *src,
+                                      const char *dest)
+{
+  char *content = NULL;
+  gsize size = 0;
+  GError *error = NULL;
+  if(!g_file_get_contents(src, &content, &size, &error)
+     || !g_file_set_contents(dest, content, size, &error))
+  {
+    dt_print(DT_DEBUG_CONTROL, "[import_from] failed to copy sidecar `%s` to `%s`: %s",
+             src, dest, error ? error->message : "unknown error");
+    g_clear_error(&error);
+  }
+  g_free(content);
+}
+
+static void _import_copy_source_sidecars(const char *filename,
+                                         const char *output)
+{
+  if(!dt_conf_get_bool("ui_last/import_copy_source_xmp")
+     || dt_image_get_xmp_mode() != DT_WRITE_XMP_ALWAYS)
+    return;
+
+  const char *ext = strrchr(filename, '.');
+  const size_t ext_offset = ext ? (size_t)(ext - filename) : strlen(filename);
+
+  GList *sidecars = dt_image_find_duplicates(filename);
+  if(sidecars)
+  {
+    // darktable-form sidecars: file.ext.xmp and versioned file_NN.ext.xmp
+    const char *oext = strrchr(output, '.');
+    for(GList *iter = sidecars; iter; iter = g_list_next(iter))
+    {
+      const char *src_xmp = iter->data;
+      // the version suffix ("" or "_NN") sits at the source extension position
+      const char *sfx_start = src_xmp + ext_offset;
+      const char *sfx_end = strchr(sfx_start, '.');
+      gchar *sfx = g_strndup(sfx_start, sfx_end ? (gsize)(sfx_end - sfx_start) : 0);
+      gchar *dest_xmp = oext
+        ? g_strdup_printf("%.*s%s%s.xmp", (int)(oext - output), output, sfx, oext)
+        : g_strconcat(output, sfx, ".xmp", NULL);
+      _import_copy_sidecar_file(src_xmp, dest_xmp);
+      g_free(sfx);
+      g_free(dest_xmp);
+    }
+    g_list_free_full(sidecars, g_free);
+    return;
+  }
+
+  // Lightroom-form fallback: source extension replaced by .xmp / .XMP
+  if(!ext) return;
+  static const char *xmp_ext[] = { ".xmp", ".XMP" };
+  for(int i = 0; i < 2; i++)
+  {
+    gchar *cand = g_strdup_printf("%.*s%s", (int)ext_offset, filename, xmp_ext[i]);
+    const gboolean found = g_file_test(cand, G_FILE_TEST_IS_REGULAR);
+    if(found)
+    {
+      gchar *dest_xmp = g_strconcat(output, ".xmp", NULL);
+      _import_copy_sidecar_file(cand, dest_xmp);
+      g_free(dest_xmp);
+    }
+    g_free(cand);
+    if(found) break;
+  }
+}
+
 static int _control_import_image_copy(const char *filename,
                                       char **prev_filename,
                                       char **prev_output,
@@ -2872,6 +2939,8 @@ static int _control_import_image_copy(const char *filename,
     utimes(output, times); // set origin file timestamps
 #endif
 
+    _import_copy_source_sidecars(filename, output);
+
     const dt_imgid_t imgid = dt_image_import(dt_import_session_film_id(session),
                                              output, FALSE, FALSE);
     if(!dt_is_valid_imgid(imgid)) dt_control_log(_("error loading file `%s'"), output);

src/libs/import.c

@@ -20,6 +20,7 @@
 #include "common/darktable.h"
 #include "common/file_location.h"
 #include "common/exif.h"
+#include "common/image.h"
 #include "common/metadata.h"
 #include "common/datetime.h"
 #include "control/conf.h"
@@ -2079,6 +2080,12 @@ static void _import_from_dialog_new(dt_lib_module_t* self)
     g_signal_connect(G_OBJECT(d->recursive), "toggled",
                      G_CALLBACK(_recursive_toggled), self);
   }
+  if(d->import_case == DT_IMPORT_COPY
+     && dt_image_get_xmp_mode() == DT_WRITE_XMP_ALWAYS)
+  {
+    dt_gui_preferences_bool(grid, "ui_last/import_copy_source_xmp", col++, line, TRUE);
+    gtk_widget_set_hexpand(gtk_grid_get_child_at(grid, col++, line), TRUE);
+  }
   GtkWidget *ignore_nonraws =
     dt_gui_preferences_bool(grid, "ui_last/import_ignore_nonraws", col++, line, TRUE);
   gtk_widget_set_hexpand(gtk_grid_get_child_at(grid, col++, line++), TRUE);