Show exception cause/context when printing an exception.

.github/workflows/test.yaml

@@ -10,28 +10,26 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Setup Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v1
+      - uses: actions/checkout@v4
+
+      - uses: astral-sh/setup-uv@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install Dependencies
         run: |
-          sudo apt remove python3-pip
-          python -m pip install --upgrade pip
-          python -m pip install . ruff mypy pytest readme_renderer
-          pip list
+          uv pip install . ruff mypy pytest readme_renderer
+          uv pip list
       - name: Type Checker
         run: |
           mypy ptpython
           ruff check .
           ruff format --check .
       - name: Run Tests
         run: |
-          ./tests/run_tests.py
+          pytest tests/
       - name: Validate README.md
         # Ensure that the README renders correctly (required for uploading to PyPI).
         run: |

examples/asyncio-python-embed.py

@@ -25,7 +25,7 @@ async def print_counter() -> None:
     Coroutine that prints counters and saves it in a global variable.
     """
     while True:
-        print("Counter: %i" % counter[0])
+        print(f"Counter: {counter[0]}")
         counter[0] += 1
         await asyncio.sleep(3)
 

examples/asyncio-ssh-python-embed.py

@@ -44,8 +44,8 @@ async def main(port: int = 8222) -> None:
     def create_server() -> MySSHServer:
         return MySSHServer(lambda: environ)
 
-    print("Listening on :%i" % port)
-    print('To connect, do "ssh localhost -p %i"' % port)
+    print(f"Listening on: {port}")
+    print(f'To connect, do "ssh localhost -p {port}"')
 
     await asyncssh.create_server(
         create_server, "", port, server_host_keys=["/etc/ssh/ssh_host_dsa_key"]

ptpython/entry_points/run_ptpython.py

@@ -30,26 +30,25 @@
 import os
 import pathlib
 import sys
+from importlib import metadata
 from textwrap import dedent
-from typing import IO
+from typing import Protocol
 
 import appdirs
 from prompt_toolkit.formatted_text import HTML
 from prompt_toolkit.shortcuts import print_formatted_text
 
 from ptpython.repl import PythonRepl, embed, enable_deprecation_warnings, run_config
 
-try:
-    from importlib import metadata  # type: ignore
-except ImportError:
-    import importlib_metadata as metadata  # type: ignore
+__all__ = ["create_parser", "get_config_and_history_file", "run"]
 
 
-__all__ = ["create_parser", "get_config_and_history_file", "run"]
+class _SupportsWrite(Protocol):
+    def write(self, s: str, /) -> object: ...
 
 
 class _Parser(argparse.ArgumentParser):
-    def print_help(self, file: IO[str] | None = None) -> None:
+    def print_help(self, file: _SupportsWrite | None = None) -> None:
         super().print_help()
         print(
             dedent(

ptpython/layout.py

@@ -108,7 +108,7 @@ def append_category(category: OptionCategory[Any]) -> None:
             tokens.extend(
                 [
                     ("class:sidebar", "  "),
-                    ("class:sidebar.title", "   %-36s" % category.title),
+                    ("class:sidebar.title", f"   {category.title:36}"),
                     ("class:sidebar", "\n"),
                 ]
             )
@@ -130,7 +130,7 @@ def goto_next(mouse_event: MouseEvent) -> None:
             sel = ",selected" if selected else ""
 
             tokens.append(("class:sidebar" + sel, " >" if selected else "  "))
-            tokens.append(("class:sidebar.label" + sel, "%-24s" % label, select_item))
+            tokens.append(("class:sidebar.label" + sel, f"{label:24}", select_item))
             tokens.append(("class:sidebar.status" + sel, " ", select_item))
             tokens.append(("class:sidebar.status" + sel, f"{status}", goto_next))
 
@@ -332,7 +332,7 @@ def get_continuation(
             width: int, line_number: int, is_soft_wrap: bool
         ) -> StyleAndTextTuples:
             if python_input.show_line_numbers and not is_soft_wrap:
-                text = ("%i " % (line_number + 1)).rjust(width)
+                text = f"{line_number + 1} ".rjust(width)
                 return [("class:line-number", text)]
             else:
                 return to_formatted_text(get_prompt_style().in2_prompt(width))
@@ -368,8 +368,7 @@ def get_text_fragments() -> StyleAndTextTuples:
         append(
             (
                 TB,
-                "%i/%i "
-                % (python_buffer.working_index + 1, len(python_buffer._working_lines)),
+                f"{python_buffer.working_index + 1}/{len(python_buffer._working_lines)} ",
             )
         )
 
@@ -492,8 +491,7 @@ def toggle_sidebar(mouse_event: MouseEvent) -> None:
         ("class:status-toolbar", " - "),
         (
             "class:status-toolbar.python-version",
-            "%s %i.%i.%i"
-            % (platform.python_implementation(), version[0], version[1], version[2]),
+            f"{platform.python_implementation()} {version[0]}.{version[1]}.{version[2]}",
         ),
         ("class:status-toolbar", " "),
     ]

ptpython/printer.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import sys
 import traceback
 from dataclasses import dataclass
 from enum import Enum
@@ -254,8 +253,7 @@ def _apply_soft_wrapping(
                     columns_in_buffer += width
                     current_line.append((style, c))
 
-            if len(current_line) > 0:
-                yield current_line
+            yield current_line
 
     def _print_paginated_formatted_text(
         self, lines: Iterable[StyleAndTextTuples]
@@ -323,14 +321,20 @@ def show_pager() -> None:
     def _format_exception_output(
         self, e: BaseException, highlight: bool
     ) -> Generator[OneStyleAndTextTuple, None, None]:
-        # Instead of just calling ``traceback.format_exc``, we take the
-        # traceback and skip the bottom calls of this framework.
-        t, v, tb = sys.exc_info()
-
-        # Required for pdb.post_mortem() to work.
-        sys.last_type, sys.last_value, sys.last_traceback = t, v, tb
-
-        tblist = list(traceback.extract_tb(tb))
+        if e.__cause__:
+            yield from self._format_exception_output(e.__cause__, highlight=highlight)
+            yield (
+                "",
+                "\nThe above exception was the direct cause of the following exception:\n\n",
+            )
+        elif e.__context__:
+            yield from self._format_exception_output(e.__context__, highlight=highlight)
+            yield (
+                "",
+                "\nDuring handling of the above exception, another exception occurred:\n\n",
+            )
+
+        tblist = list(traceback.extract_tb(e.__traceback__))
 
         for line_nr, tb_tuple in enumerate(tblist):
             if tb_tuple[0] == "<stdin>":
@@ -340,7 +344,7 @@ def _format_exception_output(
         tb_list = traceback.format_list(tblist)
         if tb_list:
             tb_list.insert(0, "Traceback (most recent call last):\n")
-        tb_list.extend(traceback.format_exception_only(t, v))
+        tb_list.extend(traceback.format_exception_only(type(e), e))
 
         tb_str = "".join(tb_list)
 

ptpython/repl.py

@@ -362,7 +362,7 @@ async def eval_async(self, line: str) -> object:
 
     def _store_eval_result(self, result: object) -> None:
         locals: dict[str, Any] = self.get_locals()
-        locals["_"] = locals["_%i" % self.current_statement_index] = result
+        locals["_"] = locals[f"_{self.current_statement_index}"] = result
 
     def get_compiler_flags(self) -> int:
         return super().get_compiler_flags() | PyCF_ALLOW_TOP_LEVEL_AWAIT
@@ -378,6 +378,10 @@ def _compile_with_flags(self, code: str, mode: str) -> Any:
         )
 
     def _handle_exception(self, e: BaseException) -> None:
+        # Required for pdb.post_mortem() to work.
+        t, v, tb = sys.exc_info()
+        sys.last_type, sys.last_value, sys.last_traceback = t, v, tb
+
         self._get_output_printer().display_exception(
             e,
             highlight=self.enable_syntax_highlighting,

setup.py

@@ -27,22 +27,21 @@
     package_data={"ptpython": ["py.typed"]},
     install_requires=[
         "appdirs",
-        "importlib_metadata;python_version<'3.8'",
         "jedi>=0.16.0",
         # Use prompt_toolkit 3.0.43, because of `OneStyleAndTextTuple` import.
         "prompt_toolkit>=3.0.43,<3.1.0",
         "pygments",
     ],
-    python_requires=">=3.7",
+    python_requires=">=3.8",
     classifiers=[
         "License :: OSI Approved :: BSD License",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
+        "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3 :: Only",
         "Programming Language :: Python",
     ],

tests/test_dummy.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+from __future__ import annotations
+
+import ptpython.completer
+import ptpython.eventloop
+import ptpython.filters
+import ptpython.history_browser
+import ptpython.key_bindings
+import ptpython.layout
+import ptpython.python_input
+import ptpython.repl
+import ptpython.style
+import ptpython.utils
+import ptpython.validator
+
+# For now there are no tests here.
+# However this is sufficient to do at least a syntax check.
+
+
+def test_dummy() -> None:
+    assert ptpython.completer
+    assert ptpython.eventloop
+    assert ptpython.filters
+    assert ptpython.history_browser
+    assert ptpython.key_bindings
+    assert ptpython.layout
+    assert ptpython.python_input
+    assert ptpython.repl
+    assert ptpython.style
+    assert ptpython.utils
+    assert ptpython.validator