Added proper support for backwards compatibility templates (#1432)

* Added proper support for backwards compatibility templates

* Removed test for old name we don't support anymore

nbconvert/exporters/templateexporter.py

@@ -548,6 +548,14 @@ def _template_paths(self, prune=True, root_dirs=None):
 
         return self.extra_template_paths + additional_paths + paths
 
+    @classmethod
+    def get_compatibility_base_template_conf(cls, name):
+        # Hard-coded base template confs to use for backwards compatibility for 5.x-only templates
+        if name == 'display_priority':
+            return dict(base_template='base')
+        if name == 'full':
+            return dict(base_template='classic', mimetypes={"text/html": True})
+
     def get_template_names(self):
         # finds a list of template names where each successive template name is the base template
         template_names = []
@@ -575,8 +583,22 @@ def get_template_names(self):
                     with open(conf_file) as f:
                         conf = recursive_update(json.load(f), conf)
             if not found_at_least_one:
-                paths = "\n\t".join(root_dirs)
-                raise ValueError('No template sub-directory with name %r found in the following paths:\n\t%s' % (base_template, paths))
+                # Check for backwards compatibility template names
+                for root_dir in root_dirs:
+                    compatibility_file = base_template + '.tpl'
+                    compatibility_path = os.path.join(root_dir, 'nbconvert', 'templates', 'compatibility', compatibility_file)
+                    if os.path.exists(compatibility_path):
+                        found_at_least_one = True
+                        warnings.warn(
+                            f"5.x template name passed '{self.template_name}'. Use 'lab' or 'classic' for new template usage.",
+                            DeprecationWarning)
+                        self.template_file = compatibility_file
+                        conf = self.get_compatibility_base_template_conf(base_template)
+                        self.template_name = conf.get('base_template')
+                        break
+                if not found_at_least_one:
+                    paths = "\n\t".join(root_dirs)
+                    raise ValueError('No template sub-directory with name %r found in the following paths:\n\t%s' % (base_template, paths))
             merged_conf = recursive_update(dict(conf), merged_conf)
             base_template = conf.get('base_template')
         conf = merged_conf

nbconvert/exporters/tests/test_rst.py

@@ -36,15 +36,6 @@ def test_export(self):
         (output, resources) = RSTExporter().from_filename(self._get_notebook())
         assert len(output) > 0
 
-    @onlyif_cmds_exist('pandoc')
-    def test_export_nbformat_template_v5_name(self):
-        """
-        We support the nbconvert v5 filename, but with a deprecation warning.
-        """
-        with pytest.warns(DeprecationWarning):
-            (output, resources) = RSTExporter(template_file='rst.tpl').from_filename(self._get_notebook())
-        assert len(output) > 0
-
     @onlyif_cmds_exist('pandoc')
     def test_empty_code_cell(self):
         """No empty code cells in rst"""

nbconvert/exporters/tests/test_templateexporter.py

@@ -43,8 +43,6 @@ def _file_extension_default(self):
     def _template_name_default(self):
         return 'python'
 
-    output_mimetype = 'text/x-python'
-
 class TestExporter(ExportersTestsBase):
     """Contains test functions for exporter.py"""
 
@@ -198,6 +196,25 @@ def test_absolute_template_name_tpl_compatibility(self):
                 exporter = self._make_exporter(config=config)
             assert exporter.template.filename == template
             assert os.path.dirname(template) in exporter.template_paths
+
+    # Can't use @pytest.mark.parametrize without removing all self.assert calls in all tests... repeating some here
+    def absolute_template_name_5x_compatibility_test(self, template, mimetype=None):
+        config = Config()
+        # We're setting the template_name instead of the template_file
+        config.TemplateExporter.template_name = template
+        with pytest.warns(DeprecationWarning):
+            exporter = self._make_exporter(config=config)
+        template_dir, template_file = os.path.split(exporter.template.filename)
+        _, compat_dir = os.path.split(template_dir)
+        assert compat_dir == 'compatibility'
+        assert template_file == template + '.tpl'
+        assert template_dir in exporter.template_paths
+
+    def test_absolute_template_name_5x_compatibility_full(self):
+        self.absolute_template_name_5x_compatibility_test('full', 'text/html')
+
+    def test_absolute_template_name_5x_compatibility_display_priority(self):
+        self.absolute_template_name_5x_compatibility_test('display_priority')
 
     # Can't use @pytest.mark.parametrize without removing all self.assert calls in all tests... repeating some here
     def relative_template_test(self, template):

share/jupyter/nbconvert/templates/compatibility/display_priority.tpl

@@ -1,2 +1,2 @@
 {{ resources.deprecated("This template is deprecated, please use base/display_priority.j2") }}
-{%- extends 'base/display_priority.j2' -%}
+{%- extends 'display_priority.j2' -%}

share/jupyter/nbconvert/templates/compatibility/full.tpl

@@ -1,2 +1,2 @@
-{{ resources.deprecated("This template is deprecated, please use lab/index.html.j2") }}
-{%- extends 'classic/index.html.j2' -%}
+{{ resources.deprecated("This template is deprecated, please use classic/index.html.j2") }}
+{%- extends 'index.html.j2' -%}