Configuration errors are reported in the console and/or in Jupyter

CHANGELOG.md

@@ -1,6 +1,9 @@
 1.6.1-dev (2020-09-??)
 ----------------------
 
+**Added**
+- Configuration errors are reported in the console and/or in Jupyter (#613)
+
 **Fixed**
 - Freeze optional dependency on `sphinx-gallery` to version `~=0.7.0` (#614)
 

jupytext/config.py

@@ -4,13 +4,19 @@
 from traitlets import Unicode, Float, Bool, Enum
 from traitlets.config import Configurable
 from traitlets.config.loader import JSONFileConfigLoader, PyFileConfigLoader
+from traitlets.traitlets import TraitError
 from .formats import (
     NOTEBOOK_EXTENSIONS,
     long_form_one_format,
     long_form_multiple_formats,
     rearrange_jupytext_metadata,
 )
 
+
+class JupytextConfigurationError(ValueError):
+    """Error in the specification of the format for the text notebook"""
+
+
 JUPYTEXT_CONFIG_FILES = [
     "jupytext",
     "jupytext.toml",
@@ -287,25 +293,28 @@ def find_jupytext_configuration_file(path, search_parent_dirs=True):
 def load_jupytext_configuration_file(jupytext_config_file):
     """Read a Jupytext config file, and return a JupytextConfig object"""
 
-    if jupytext_config_file.endswith((".toml", "jupytext")):
-        import toml
+    try:
+        if jupytext_config_file.endswith((".toml", "jupytext")):
+            import toml
 
-        config = toml.load(jupytext_config_file)
-        return JupytextConfiguration(**config)
+            config = toml.load(jupytext_config_file)
+            return config
 
-    if jupytext_config_file.endswith((".yml", ".yaml")):
-        with open(jupytext_config_file) as stream:
-            config = yaml.safe_load(stream)
-        return JupytextConfiguration(**config)
+        if jupytext_config_file.endswith((".yml", ".yaml")):
+            with open(jupytext_config_file) as stream:
+                config = yaml.safe_load(stream)
+            return config
 
-    if jupytext_config_file.endswith(".py"):
-        return JupytextConfiguration(
-            **PyFileConfigLoader(jupytext_config_file).load_config()
-        )
+        if jupytext_config_file.endswith(".py"):
+            return PyFileConfigLoader(jupytext_config_file).load_config()
 
-    return JupytextConfiguration(
-        **JSONFileConfigLoader(jupytext_config_file).load_config()
-    )
+        return JSONFileConfigLoader(jupytext_config_file).load_config()
+    except (ValueError, NameError) as err:
+        raise JupytextConfigurationError(
+            "The Jupytext configuration file {} is incorrect: {}".format(
+                jupytext_config_file, err
+            )
+        )
 
 
 def load_jupytext_config(nb_file):
@@ -315,7 +324,25 @@ def load_jupytext_config(nb_file):
         return None
     if os.path.isfile(nb_file) and os.path.samefile(config_file, nb_file):
         return None
-    return load_jupytext_configuration_file(config_file)
+    config_values = load_jupytext_configuration_file(config_file)
+    try:
+        config = JupytextConfiguration(**config_values)
+    except TraitError as err:
+        raise JupytextConfigurationError(
+            "The Jupytext configuration file {} is incorrect: {}".format(
+                config_file, err
+            )
+        )
+    invalid_options = set(config_values).difference(dir(JupytextConfiguration()))
+    if any(invalid_options):
+        raise JupytextConfigurationError(
+            "The Jupytext configuration file {} is incorrect: options {} are not supported".format(
+                config_file, ",".join(invalid_options)
+            )
+        )
+    return config
+
+    return
 
 
 def prepare_notebook_for_save(nbk, config, path):

jupytext/contentsmanager.py

@@ -33,6 +33,7 @@
 from .kernels import set_kernelspec_from_language
 from .config import (
     JupytextConfiguration,
+    JupytextConfigurationError,
     preferred_format,
     load_jupytext_config,
     prepare_notebook_for_save,
@@ -435,9 +436,12 @@ def get_config(self, path, use_cache=False):
                     self.cached_config.timestamp + timedelta(seconds=1) < datetime.now()
                 )
             ):
-                self.cached_config.path = parent_dir
-                self.cached_config.timestamp = datetime.now()
-                self.cached_config.config = load_jupytext_config(parent_dir)
+                try:
+                    self.cached_config.path = parent_dir
+                    self.cached_config.timestamp = datetime.now()
+                    self.cached_config.config = load_jupytext_config(parent_dir)
+                except JupytextConfigurationError as err:
+                    raise HTTPError(400, "{}".format(err))
 
             return self.cached_config.config or self
 

tests/test_cm_config.py

@@ -6,6 +6,8 @@
     import mock
 from nbformat.v4.nbbase import new_notebook, new_markdown_cell, new_code_cell
 from nbformat import read
+import pytest
+from tornado.web import HTTPError
 import jupytext
 
 SAMPLE_NOTEBOOK = new_notebook(
@@ -64,4 +66,39 @@ def test_pairing_through_config_leaves_ipynb_unmodified(tmpdir):
     assert py_file.isfile()
 
     nb = read(nb_file, as_version=4)
-    assert 'jupytext' not in nb.metadata
+    assert "jupytext" not in nb.metadata
+
+
+@pytest.mark.parametrize(
+    "cfg_file,cfg_text",
+    [
+        # Should be false, not False
+        ("jupytext.toml", "hide_notebook_metadata = False"),
+        ("jupytext.toml", 'hide_notebook_metadata = "False"'),
+        ("jupytext.toml", "not_a_jupytext_option = true"),
+        ("jupytext.json", '{"notebook_metadata_filter":"-all",}'),
+        (".jupytext.py", "c.not_a_jupytext_option = True"),
+        (".jupytext.py", "c.hide_notebook_metadata = true"),
+    ],
+)
+def test_incorrect_config_message(tmpdir, cfg_file, cfg_text):
+    cm = jupytext.TextFileContentsManager()
+    cm.root_dir = str(tmpdir)
+
+    cfg_file = tmpdir.join(cfg_file)
+    cfg_file.write(cfg_text)
+
+    tmpdir.join("empty.ipynb").write("{}")
+
+    expected_message = "The Jupytext configuration file {} is incorrect".format(
+        cfg_file
+    )
+
+    # This is a regexp so we have to escape the path separator on Windows
+    expected_message = expected_message.replace("\\", "\\\\")
+
+    with pytest.raises(HTTPError, match=expected_message):
+        cm.get("empty.ipynb", type="notebook", content=False)
+
+    with pytest.raises(HTTPError, match=expected_message):
+        cm.save(dict(type="notebook", content=SAMPLE_NOTEBOOK), "notebook.ipynb")

tests/test_config.py

@@ -3,6 +3,7 @@
 from jupytext.config import (
     find_jupytext_configuration_file,
     load_jupytext_configuration_file,
+    JupytextConfiguration,
 )
 
 
@@ -83,6 +84,7 @@ def test_load_jupytext_configuration_file(tmpdir, config_file):
         )
 
     config = load_jupytext_configuration_file(str(full_config_path))
+    config = JupytextConfiguration(**config)
     assert config.default_jupytext_formats == "ipynb,py:percent"
     assert config.default_notebook_metadata_filter == "all"
     assert config.default_cell_metadata_filter == "all"