Add type checking (#1930)

.github/workflows/tests.yml

@@ -67,6 +67,7 @@ jobs:
       - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
       -  name: Run Linters
          run: |
+          hatch run typing:test
           hatch run lint:style
           pipx run interrogate -v .
           pipx run doc8 --max-line-length=200  --ignore-path=docs/source/other/full-config.rst

nbconvert/conftest.py

@@ -3,4 +3,4 @@
 import os
 
 if os.name == "nt":
-    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())  # type:ignore

nbconvert/exporters/exporter.py

@@ -11,10 +11,10 @@
 import datetime
 import os
 import sys
-from typing import Optional
+import typing as t
 
 import nbformat
-from nbformat import validator
+from nbformat import NotebookNode, validator
 from traitlets import Bool, HasTraits, List, TraitError, Unicode
 from traitlets.config import Config
 from traitlets.config.configurable import LoggingConfigurable
@@ -75,7 +75,7 @@ class Exporter(LoggingConfigurable):
 
     # Should this converter be accessible from the notebook front-end?
     # If so, should be a friendly name to display (and possibly translated).
-    export_from_notebook = None
+    export_from_notebook: str = None  # type:ignore
 
     # Configurability, allows the user to easily add filters and preprocessors.
     preprocessors = List(help="""List of preprocessors, by name or namespace, to enable.""").tag(
@@ -126,7 +126,9 @@ def __init__(self, config=None, **kw):
     def default_config(self):
         return Config()
 
-    def from_notebook_node(self, nb, resources=None, **kw):
+    def from_notebook_node(
+        self, nb: NotebookNode, resources: t.Optional[t.Any] = None, **kw: t.Any
+    ) -> t.Tuple[NotebookNode, t.Dict]:
         """
         Convert a notebook from a notebook node instance.
 
@@ -157,7 +159,9 @@ def from_notebook_node(self, nb, resources=None, **kw):
         self._nb_metadata[notebook_name] = nb_copy.metadata
         return nb_copy, resources
 
-    def from_filename(self, filename: str, resources: Optional[dict] = None, **kw):
+    def from_filename(
+        self, filename: str, resources: t.Optional[dict] = None, **kw: t.Any
+    ) -> t.Tuple[NotebookNode, t.Dict]:
         """
         Convert a notebook from a notebook file.
 
@@ -193,7 +197,9 @@ def from_filename(self, filename: str, resources: Optional[dict] = None, **kw):
         with open(filename, encoding="utf-8") as f:
             return self.from_file(f, resources=resources, **kw)
 
-    def from_file(self, file_stream, resources=None, **kw):
+    def from_file(
+        self, file_stream: t.Any, resources: t.Optional[dict] = None, **kw: t.Any
+    ) -> t.Tuple[NotebookNode, dict]:
         """
         Convert a notebook from a notebook file.
 

nbconvert/exporters/html.py

@@ -8,6 +8,7 @@
 import mimetypes
 import os
 from pathlib import Path
+from typing import Any, Dict, Optional, Tuple
 
 import jinja2
 import markupsafe
@@ -16,11 +17,12 @@
 from traitlets.config import Config
 
 if tuple(int(x) for x in jinja2.__version__.split(".")[:3]) < (3, 0, 0):
-    from jinja2 import contextfilter
+    from jinja2 import contextfilter  # type:ignore
 else:
     from jinja2 import pass_context as contextfilter
 
 from jinja2.loaders import split_template_path
+from nbformat import NotebookNode
 
 from nbconvert.filters.highlight import Highlight2HTML
 from nbconvert.filters.markdown_mistune import IPythonRenderer, MarkdownWithMath
@@ -208,7 +210,9 @@ def default_filters(self):
         yield from super().default_filters()
         yield ("markdown2html", self.markdown2html)
 
-    def from_notebook_node(self, nb, resources=None, **kw):
+    def from_notebook_node(  # type:ignore
+        self, nb: NotebookNode, resources: Optional[Dict] = None, **kw: Any
+    ) -> Tuple[str, Dict]:
         """Convert from notebook node."""
         langinfo = nb.metadata.get("language_info", {})
         lexer = langinfo.get("pygments_lexer", langinfo.get("name", None))
@@ -247,11 +251,9 @@ def resources_include_lab_theme(name):
                     # Replace asset url by a base64 dataurl
                     with open(theme_path / asset, "rb") as assetfile:
                         base64_data = base64.b64encode(assetfile.read())
-                        base64_data = base64_data.replace(b"\n", b"").decode("ascii")
+                        base64_str = base64_data.replace(b"\n", b"").decode("ascii")
 
-                        data = data.replace(
-                            local_url, f"url(data:{mime_type};base64,{base64_data})"
-                        )
+                        data = data.replace(local_url, f"url(data:{mime_type};base64,{base64_str})")
 
             code = """<style type="text/css">\n%s</style>""" % data
             return markupsafe.Markup(code)

nbconvert/exporters/pdf.py

@@ -122,7 +122,7 @@ def run_command(self, command_list, filename, count, log_function, raise_on_fail
 
         shell = sys.platform == "win32"
         if shell:
-            command = subprocess.list2cmdline(command)
+            command = subprocess.list2cmdline(command)  # type:ignore
         env = os.environ.copy()
         prepend_to_env_search_path("TEXINPUTS", self.texinputs, env)
         prepend_to_env_search_path("BIBINPUTS", self.texinputs, env)
@@ -144,17 +144,13 @@ def run_command(self, command_list, filename, count, log_function, raise_on_fail
                     if self.verbose:
                         # verbose means I didn't capture stdout with PIPE,
                         # so it's already been displayed and `out` is None.
-                        out = ""
+                        out_str = ""
                     else:
-                        out = out.decode("utf-8", "replace")
+                        out_str = out.decode("utf-8", "replace")
                     log_function(command, out)
-                    self._captured_output.append(out)
+                    self._captured_output.append(out_str)
                     if raise_on_failure:
-                        raise raise_on_failure(
-                            'Failed to run "{command}" command:\n{output}'.format(
-                                command=command, output=out
-                            )
-                        )
+                        raise raise_on_failure(f'Failed to run "{command}" command:\n{out_str}')
                     return False  # failure
         return True  # success
 

nbconvert/exporters/qt_exporter.py

@@ -12,6 +12,7 @@ class QtExporter(HTMLExporter):
     """A qt exporter."""
 
     paginate = None
+    format = ""
 
     @default("file_extension")
     def _file_extension_default(self):

nbconvert/exporters/qt_screenshot.py

@@ -2,10 +2,10 @@
 import os
 
 try:
-    from PyQt5 import QtCore
-    from PyQt5.QtGui import QPageLayout, QPageSize
-    from PyQt5.QtWebEngineWidgets import QWebEngineSettings, QWebEngineView
-    from PyQt5.QtWidgets import QApplication
+    from PyQt5 import QtCore  # type:ignore
+    from PyQt5.QtGui import QPageLayout, QPageSize  # type:ignore
+    from PyQt5.QtWebEngineWidgets import QWebEngineSettings, QWebEngineView  # type:ignore
+    from PyQt5.QtWidgets import QApplication  # type:ignore
 
     QT_INSTALLED = True
 except ModuleNotFoundError:
@@ -40,7 +40,7 @@ def capture(self, url, output_file, paginate):
 
                 def cleanup(*args):
                     """Cleanup the app."""
-                    self.app.quit()
+                    self.app.quit()  # type:ignore
                     self.get_data()
 
                 self.page().pdfPrintingFinished.connect(cleanup)
@@ -49,7 +49,7 @@ def cleanup(*args):
             else:
                 raise RuntimeError(f"Export file extension not supported: {output_file}")
             self.show()
-            self.app.exec()
+            self.app.exec()  # type:ignore
 
         def on_loaded(self):
             """Handle app load."""
@@ -76,7 +76,7 @@ def export_pdf(self):
         def export_png(self):
             """Export to png."""
             self.grab().save(self.output_file, "PNG")
-            self.app.quit()
+            self.app.quit()  # type:ignore
             self.get_data()
 
         def get_data(self):

nbconvert/exporters/templateexporter.py

@@ -9,6 +9,7 @@
 import html
 import json
 import os
+import typing as t
 import uuid
 import warnings
 from pathlib import Path
@@ -22,6 +23,7 @@
     TemplateNotFound,
 )
 from jupyter_core.paths import jupyter_path
+from nbformat import NotebookNode
 from traitlets import Bool, Dict, HasTraits, List, Unicode, default, observe, validate
 from traitlets.config import Config
 from traitlets.utils.importstring import import_item
@@ -221,7 +223,7 @@ def _template_name_validate(self, change):
     def _template_file_changed(self, change):
         new = change["new"]
         if new == "default":
-            self.template_file = self.default_template
+            self.template_file = self.default_template  # type:ignore
             return
         # check if template_file is a file path
         # rather than a name already on template_path
@@ -374,7 +376,21 @@ def _load_template(self):
         self.log.debug("    template_paths: %s", os.pathsep.join(self.template_paths))
         return self.environment.get_template(template_file)
 
-    def from_notebook_node(self, nb, resources=None, **kw):
+    def from_filename(  # type:ignore
+        self, filename: str, resources: t.Optional[dict] = None, **kw: t.Any
+    ) -> t.Tuple[str, dict]:
+        """Convert a notebook from a filename."""
+        return super().from_filename(filename, resources, **kw)  # type:ignore
+
+    def from_file(  # type:ignore
+        self, file_stream: t.Any, resources: t.Optional[dict] = None, **kw: t.Any
+    ) -> t.Tuple[str, dict]:
+        """Convert a notebook from a file."""
+        return super().from_file(file_stream, resources, **kw)  # type:ignore
+
+    def from_notebook_node(  # type:ignore
+        self, nb: NotebookNode, resources: t.Optional[dict] = None, **kw: t.Any
+    ) -> t.Tuple[str, dict]:
         """
         Convert a notebook from a notebook node instance.
 
@@ -515,7 +531,7 @@ def _init_preprocessors(self):
         #  * We rely on recursive_update, which can only merge dicts, lists will be overwritten
         #  * We can use the key with numerical prefixing to guarantee ordering (/etc/*.d/XY-file style)
         #  * We can disable preprocessors by overwriting the value with None
-        for _, preprocessor in sorted(preprocessors.items(), key=lambda x: x[0]):
+        for _, preprocessor in sorted(preprocessors.items(), key=lambda x: x[0]):  # type:ignore
             if preprocessor is not None:
                 kwargs = preprocessor.copy()
                 preprocessor_cls = kwargs.pop("type")
@@ -526,7 +542,7 @@ def _init_preprocessors(self):
                 self.register_preprocessor(preprocessor)
 
     def _get_conf(self):
-        conf = {}  # the configuration once all conf files are merged
+        conf: dict = {}  # the configuration once all conf files are merged
         for path in map(Path, self.template_paths):
             conf_path = path / "conf.json"
             if conf_path.exists():
@@ -583,10 +599,10 @@ def get_template_names(self):
         template_names = []
         root_dirs = self.get_prefix_root_dirs()
         base_template = self.template_name
-        merged_conf = {}  # the configuration once all conf files are merged
+        merged_conf: dict = {}  # the configuration once all conf files are merged
         while base_template is not None:
             template_names.append(base_template)
-            conf = {}
+            conf: dict = {}
             found_at_least_one = False
             for base_dir in self.extra_template_basedirs:
                 template_dir = os.path.join(base_dir, base_template)

nbconvert/exporters/tests/test_asciidoc.py

@@ -30,7 +30,7 @@
 class TestASCIIDocExporter(ExportersTestsBase):
     """Tests for ASCIIDocExporter"""
 
-    exporter_class = ASCIIDocExporter
+    exporter_class = ASCIIDocExporter  # type:ignore
 
     def test_constructor(self):
         """

nbconvert/exporters/tests/test_html.py

@@ -15,8 +15,8 @@
 class TestHTMLExporter(ExportersTestsBase):
     """Tests for HTMLExporter"""
 
-    exporter_class = HTMLExporter
-    should_include_raw = ["html"]
+    exporter_class = HTMLExporter  # type:ignore
+    should_include_raw = ["html"]  # type:ignore
 
     def test_constructor(self):
         """
@@ -78,6 +78,7 @@ def test_png_metadata(self):
         )
         check_for_png = re.compile(r'<img src="[^"]*?"([^>]*?)>')
         result = check_for_png.search(output)
+        assert result
         attr_string = result.group(1)
         assert "width" in attr_string
         assert "height" in attr_string
@@ -104,6 +105,7 @@ def test_attachments(self):
         )
         check_for_png = re.compile(r'<img src="[^"]*?"([^>]*?)>')
         result = check_for_png.search(output)
+        assert result
         self.assertTrue(result.group(0).strip().startswith('<img src="data:image/png;base64,iVBOR'))
         self.assertTrue(result.group(1).strip().startswith('alt="image.png"'))
 

nbconvert/exporters/tests/test_latex.py

@@ -22,8 +22,8 @@
 class TestLatexExporter(ExportersTestsBase):
     """Contains test functions for latex.py"""
 
-    exporter_class = LatexExporter
-    should_include_raw = ["latex"]
+    exporter_class = LatexExporter  # type:ignore
+    should_include_raw = ["latex"]  # type:ignore
 
     def test_constructor(self):
         """

nbconvert/exporters/tests/test_markdown.py

@@ -23,8 +23,8 @@
 class TestMarkdownExporter(ExportersTestsBase):
     """Tests for MarkdownExporter"""
 
-    exporter_class = MarkdownExporter
-    should_include_raw = ["markdown", "html"]
+    exporter_class = MarkdownExporter  # type:ignore
+    should_include_raw = ["markdown", "html"]  # type:ignore
 
     def test_constructor(self):
         """

nbconvert/exporters/tests/test_notebook.py

@@ -16,26 +16,28 @@
 class TestNotebookExporter(ExportersTestsBase):
     """Contains test functions for notebook.py"""
 
-    exporter_class = NotebookExporter
+    exporter_class = NotebookExporter  # type:ignore
 
     def test_export(self):
         """
         Does the NotebookExporter return the file unchanged?
         """
         with open(self._get_notebook()) as f:
             file_contents = f.read()
-        (output, resources) = self.exporter_class().from_filename(self._get_notebook())
+        (output, resources) = self.exporter_class().from_filename(  # type:ignore
+            self._get_notebook()
+        )
         assert len(output) > 0
         assert_big_text_equal(output, file_contents)
 
     def test_downgrade_3(self):
-        exporter = self.exporter_class(nbformat_version=3)
+        exporter = self.exporter_class(nbformat_version=3)  # type:ignore
         (output, resources) = exporter.from_filename(self._get_notebook())
         nb = json.loads(output)
         validate(nb)
 
     def test_downgrade_2(self):
-        exporter = self.exporter_class(nbformat_version=2)
+        exporter = self.exporter_class(nbformat_version=2)  # type:ignore
         (output, resources) = exporter.from_filename(self._get_notebook())
         nb = json.loads(output)
         self.assertEqual(nb["nbformat"], 2)

nbconvert/exporters/tests/test_pdf.py

@@ -19,11 +19,11 @@
 class TestPDF(ExportersTestsBase):
     """Test PDF export"""
 
-    exporter_class = PDFExporter
+    exporter_class = PDFExporter  # type:ignore
 
     def test_constructor(self):
         """Can a PDFExporter be constructed?"""
-        self.exporter_class()
+        self.exporter_class()  # type:ignore
 
     @onlyif_cmds_exist("xelatex", "pandoc")
     def test_export(self):
@@ -32,7 +32,9 @@ def test_export(self):
             file_name = os.path.basename(self._get_notebook())
             newpath = os.path.join(td, file_name)
             shutil.copy(self._get_notebook(), newpath)
-            (output, resources) = self.exporter_class(latex_count=1).from_filename(newpath)
+            (output, resources) = self.exporter_class(latex_count=1).from_filename(  # type:ignore
+                newpath
+            )
             self.assertIsInstance(output, bytes)
             assert len(output) > 0
             # all temporary file should be cleaned up