Handle FieldError during import via Admin UI

docs/changelog.rst

@@ -20,6 +20,7 @@ Changelog
   (#1735)
 - Updated Admin integration documentation to clarify how to save custom form values (#1746)
 - Updated test coverage to include error row when ``collect_failed_rows`` is ``True`` (#1753)
+- Fixed handling of :attr:`~import_export.exceptions.FieldError` during Admin import (#1755)
 
 4.0.0-beta.2 (2023-12-09)
 -------------------------

import_export/admin.py

@@ -18,6 +18,7 @@
 from django.utils.translation import gettext_lazy as _
 from django.views.decorators.http import require_POST
 
+from .exceptions import FieldError
 from .forms import ConfirmImportForm, ImportForm, SelectableFieldsExportForm
 from .mixins import BaseExportMixin, BaseImportMixin
 from .results import RowResult
@@ -502,21 +503,27 @@ def import_action(self, request, *args, **kwargs):
                     imp_kwargs = self.get_import_data_kwargs(
                         request, *args, form=import_form, **kwargs
                     )
-                    result = resource.import_data(
-                        dataset,
-                        dry_run=True,
-                        raise_errors=False,
-                        file_name=import_file.name,
-                        user=request.user,
-                        **imp_kwargs,
-                    )
+                    try:
+                        result = resource.import_data(
+                            dataset,
+                            dry_run=True,
+                            raise_errors=False,
+                            file_name=import_file.name,
+                            user=request.user,
+                            **imp_kwargs,
+                        )
+                        context["result"] = result
 
-                    context["result"] = result
+                        if (
+                            not result.has_errors()
+                            and not result.has_validation_errors()
+                        ):
+                            context["confirm_form"] = self.create_confirm_form(
+                                request, import_form=import_form
+                            )
+                    except FieldError as e:
+                        messages.error(request, str(e))
 
-                    if not result.has_errors() and not result.has_validation_errors():
-                        context["confirm_form"] = self.create_confirm_form(
-                            request, import_form=import_form
-                        )
         else:
             res_kwargs = self.get_import_resource_kwargs(
                 request, form=import_form, **kwargs

tests/core/tests/admin_integration/test_import.py

@@ -19,6 +19,7 @@
 from django.utils.translation import gettext_lazy as _
 
 from import_export.admin import ExportMixin
+from import_export.exceptions import FieldError
 from import_export.formats import base_formats
 from import_export.formats.base_formats import XLSX
 from import_export.resources import ModelResource
@@ -202,6 +203,17 @@ def test_import_action_handles_ValueError_as_form_error(self):
         else:
             self.assertFormError(response, "form", "import_file", target_msg)
 
+    def test_import_action_handles_FieldError(self):
+        # issue 1722
+        with mock.patch(
+            "import_export.resources.Resource._check_import_id_fields"
+        ) as mock_check_import_id_fields:
+            mock_check_import_id_fields.side_effect = FieldError("some unknown error")
+            response = self._do_import_post(self.book_import_url, "books.csv")
+        self.assertEqual(response.status_code, 200)
+        target_msg = "Some unknown error"
+        self.assertIn(target_msg, str(response.content))
+
     @override_settings(LANGUAGE_CODE="es")
     def test_import_action_handles_ValueError_as_form_error_with_translation(self):
         with mock.patch(