implemented debug() editor function which lets you navigate in the stack frame

gdementen · gdementen · commit 69e657757de3 · 2019-10-21T12:05:09.000+02:00
run_editor_on_exception now uses debug so that we can navigate the traceback
diff --git a/doc/source/changes/version_0_32.rst.inc b/doc/source/changes/version_0_32.rst.inc
@@ -1,6 +1,11 @@
 ﻿.. py:currentmodule:: larray_editor
 
-.. _misc_editor:
+New features
+^^^^^^^^^^^^
+
+* added :py:obj:`debug()` function which opens an editor window with an extra widget to navigate back in the call
+  stack (the chain of functions called to reach the current line of code).
+
 
 Miscellaneous improvements
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -11,6 +16,9 @@ Miscellaneous improvements
 * Sizes of the main window and the resizable components are saved when closing the viewer and restored
   when the viewer is reopened (closes :editor_issue:`165`).
 
+* :py:obj:`run_editor_on_exception()` now uses :py:obj:`debug()` so that one can inspect what the state was in all
+  functions traversed to reach the code which triggered the exception.
+
 
 Fixes
 ^^^^^
diff --git a/larray_editor/api.py b/larray_editor/api.py
@@ -11,8 +11,9 @@
 import larray as la
 
 from larray_editor.editor import REOPEN_LAST_FILE, MappingEditor, ArrayEditor
+from larray_editor.traceback_tools import extract_stack, extract_tb, StackSummary
 
-__all__ = ['view', 'edit', 'compare', 'REOPEN_LAST_FILE', 'run_editor_on_exception']
+__all__ = ['view', 'edit', 'debug', 'compare', 'REOPEN_LAST_FILE', 'run_editor_on_exception']
 
 
 def qapplication():
@@ -104,7 +105,10 @@ def edit(obj=None, title='', minvalue=None, maxvalue=None, readonly=False, depth
     >>> # will open an editor for a1 only
     >>> edit(a1)                                                                                       # doctest: +SKIP
     """
-    install_except_hook()
+    # we don't use install_except_hook/restore_except_hook so that we can restore the hook actually used when
+    # this function is called instead of the one which was used when the module was loaded.
+    orig_except_hook = sys.excepthook
+    sys.excepthook = _qt_except_hook
 
     _app = QApplication.instance()
     if _app is None:
@@ -147,7 +151,7 @@ def edit(obj=None, title='', minvalue=None, maxvalue=None, readonly=False, depth
         dlg.show()
         _app.exec_()
 
-    restore_except_hook()
+    sys.excepthook = orig_except_hook
 
 
 def view(obj=None, title='', depth=0, display_caller_info=True):
@@ -182,6 +186,45 @@ def view(obj=None, title='', depth=0, display_caller_info=True):
     edit(obj, title=title, readonly=True, depth=depth + 1, display_caller_info=display_caller_info)
 
 
+def _debug(stack_summary, stack_pos=None):
+    # we don't use install_except_hook/restore_except_hook so that we can restore the hook actually used when
+    # this function is called instead of the one which was used when the module was loaded.
+    orig_except_hook = sys.excepthook
+    sys.excepthook = _qt_except_hook
+
+    _app = QApplication.instance()
+    if _app is None:
+        _app = qapplication()
+        _app.setOrganizationName("LArray")
+        _app.setApplicationName("Debugger")
+        parent = None
+    else:
+        parent = _app.activeWindow()
+
+    assert isinstance(stack_summary, StackSummary)
+    dlg = MappingEditor(parent)
+    setup_ok = dlg.setup_and_check(stack_summary, stack_pos=stack_pos)
+    if setup_ok:
+        dlg.show()
+        _app.exec_()
+
+    sys.excepthook = orig_except_hook
+
+
+def debug(depth=0):
+    r"""
+    Opens a new debug window.
+
+    Parameters
+    ----------
+    depth : int, optional
+        Stack depth where to look for variables. Defaults to 0 (where this function was called).
+    """
+    caller_frame = sys._getframe(depth + 1)
+    stack_summary = extract_stack(caller_frame)
+    _debug(stack_summary)
+
+
 def compare(*args, **kwargs):
     """
     Opens a new comparator window, comparing arrays or sessions.
@@ -223,7 +266,10 @@ def compare(*args, **kwargs):
     >>> compare(a1, a2, title='first comparison')                                                      # doctest: +SKIP
     >>> compare(a1 + 1, a2, title='second comparison', names=['a1+1', 'a2'])                           # doctest: +SKIP
     """
-    install_except_hook()
+    # we don't use install_except_hook/restore_except_hook so that we can restore the hook actually used when
+    # this function is called instead of the one which was used when the module was loaded.
+    orig_except_hook = sys.excepthook
+    sys.excepthook = _qt_except_hook
 
     title = kwargs.pop('title', '')
     names = kwargs.pop('names', None)
@@ -268,7 +314,8 @@ def get_name(i, obj, depth=0):
         dlg.show()
         _app.exec_()
 
-    restore_except_hook()
+    sys.excepthook = orig_except_hook
+
 
 _orig_except_hook = sys.excepthook
 
@@ -308,15 +355,7 @@ def _trace_code_file(tb):
     return os.path.normpath(tb.tb_frame.f_code.co_filename)
 
 
-def _get_vars_from_frame(frame):
-    frame_globals, frame_locals = frame.f_globals, frame.f_locals
-    d = collections.OrderedDict()
-    d.update([(k, frame_globals[k]) for k in sorted(frame_globals.keys())])
-    d.update([(k, frame_locals[k]) for k in sorted(frame_locals.keys())])
-    return d
-
-
-def _get_debug_except_hook(root_path=None, usercode_traceback=True):
+def _get_debug_except_hook(root_path=None, usercode_traceback=True, usercode_frame=True):
     try:
         main_file = os.path.abspath(sys.modules['__main__'].__file__)
     except AttributeError:
@@ -334,29 +373,31 @@ def excepthook(type, value, tback):
 
         main_tb = current_tb if _trace_code_file(current_tb) == main_file else tback
 
-        if usercode_traceback:
+        user_tb_length = None
+        if usercode_traceback or usercode_frame:
             if main_tb != current_tb:
                 print("Warning: couldn't find frame corresponding to user code, showing the full traceback "
                       "and inspect last frame instead (which might be in library code)",
                       file=sys.stderr)
-                limit = None
             else:
                 user_tb_length = 1
                 # continue as long as the next tb is still in the current project
                 while current_tb.tb_next and _trace_code_file(current_tb.tb_next).startswith(root_path):
                     current_tb = current_tb.tb_next
                     user_tb_length += 1
-                limit = user_tb_length
-        else:
-            limit = None
-        traceback.print_exception(type, value, main_tb, limit=limit)
+
+        tb_limit = user_tb_length if usercode_traceback else None
+        traceback.print_exception(type, value, main_tb, limit=tb_limit)
+
+        stack = extract_tb(main_tb, limit=tb_limit)
+        stack_pos = user_tb_length - 1 if user_tb_length is not None and usercode_frame else None
         print("\nlaunching larray editor to debug...", file=sys.stderr)
-        edit(_get_vars_from_frame(current_tb.tb_frame))
+        _debug(stack, stack_pos=stack_pos)
 
     return excepthook
 
 
-def run_editor_on_exception(root_path=None, usercode_traceback=True):
+def run_editor_on_exception(root_path=None, usercode_traceback=True, usercode_frame=True):
     """
     Run the editor when an unhandled exception (a fatal error) happens.
 
@@ -367,9 +408,13 @@ def run_editor_on_exception(root_path=None, usercode_traceback=True):
     usercode_traceback : bool, optional
         Whether or not to show only the part of the traceback (error log) which corresponds to the user code.
         Otherwise, it will show the complete traceback, including code inside libraries. Defaults to True.
+    usercode_frame : bool, optional
+        Whether or not to start the debug window in the frame corresponding to the user code.
+        This argument is ignored (it is always True) if usercode_traceback is True. Defaults to True.
 
     Notes
     -----
     sets sys.excepthook
     """
-    sys.excepthook = _get_debug_except_hook(root_path=root_path, usercode_traceback=usercode_traceback)
+    sys.excepthook = _get_debug_except_hook(root_path=root_path, usercode_traceback=usercode_traceback,
+                                            usercode_frame=usercode_frame)
diff --git a/larray_editor/editor.py b/larray_editor/editor.py
@@ -1,11 +1,13 @@
 import os
 import re
+
 import matplotlib
 import numpy as np
 import collections
 
 import larray as la
 
+from larray_editor.traceback_tools import StackSummary
 from larray_editor.utils import (PY2, PYQT5, _, create_action, show_figure, ima, commonpath, dependencies,
                                  get_versions, get_documentation_url, urls, RecentlyUsedList)
 from larray_editor.arraywidget import ArrayEditorWidget
@@ -14,7 +16,7 @@
 from qtpy.QtCore import Qt, QUrl, QSettings
 from qtpy.QtGui import QDesktopServices, QKeySequence
 from qtpy.QtWidgets import (QMainWindow, QWidget, QListWidget, QListWidgetItem, QSplitter, QFileDialog, QPushButton,
-                            QDialogButtonBox, QShortcut, QHBoxLayout, QVBoxLayout, QGridLayout, QLineEdit, QUndoStack,
+                            QDialogButtonBox, QShortcut, QVBoxLayout, QGridLayout, QLineEdit, QUndoStack,
                             QCheckBox, QComboBox, QMessageBox, QDialog, QInputDialog, QLabel, QGroupBox, QRadioButton)
 
 try:
@@ -338,7 +340,7 @@ def __init__(self, parent=None):
 
         self.setup_menu_bar()
 
-    def _setup_and_check(self, widget, data, title, readonly, **kwargs):
+    def _setup_and_check(self, widget, data, title, readonly, stack_pos=None):
         """Setup MappingEditor"""
         layout = QVBoxLayout()
         widget.setLayout(layout)
@@ -363,6 +365,7 @@ def _setup_and_check(self, widget, data, title, readonly, **kwargs):
             kernel = kernel_manager.kernel
 
             # TODO: use self._reset() instead
+            # FIXME: when using the editor as a debugger this is annoying
             kernel.shell.run_cell('from larray import *')
             text_formatter = kernel.shell.display_formatter.formatters['text/plain']
 
@@ -405,9 +408,34 @@ def void_formatter(array, *args, **kwargs):
             right_panel_widget.setLayout(right_panel_layout)
 
         main_splitter = QSplitter(Qt.Horizontal)
-        main_splitter.addWidget(self._listwidget)
+        debug = isinstance(data, StackSummary)
+        if debug:
+            self._stack_frame_widget = QListWidget(self)
+            stack_frame_widget = self._stack_frame_widget
+            stack_frame_widget.itemSelectionChanged.connect(self.on_stack_frame_changed)
+            stack_frame_widget.setMinimumWidth(60)
+
+            for frame_summary in data:
+                funcname = frame_summary.name
+                filename = os.path.basename(frame_summary.filename)
+                listitem = QListWidgetItem(stack_frame_widget)
+                listitem.setText("{}, {}:{}".format(funcname, filename, frame_summary.lineno))
+                # we store the frame summary object in the user data of the list
+                listitem.setData(Qt.UserRole, frame_summary)
+                listitem.setToolTip(frame_summary.line)
+            row = stack_pos if stack_pos is not None else len(data) - 1
+            stack_frame_widget.setCurrentRow(row)
+
+            left_panel_widget = QSplitter(Qt.Vertical)
+            left_panel_widget.addWidget(self._listwidget)
+            left_panel_widget.addWidget(stack_frame_widget)
+            left_panel_widget.setSizes([500, 200])
+            data = self.data
+        else:
+            left_panel_widget = self._listwidget
+        main_splitter.addWidget(left_panel_widget)
         main_splitter.addWidget(right_panel_widget)
-        main_splitter.setSizes([10, 90])
+        main_splitter.setSizes([180, 620])
         main_splitter.setCollapsible(1, False)
         self.widget_state_settings['main_splitter'] = main_splitter
 
@@ -427,8 +455,7 @@ def void_formatter(array, *args, **kwargs):
             else:
                 QMessageBox.critical(self, "Error", "File {} could not be found".format(data))
                 self.new()
-        # convert input data to Session if not
-        else:
+        elif not debug:
             self._push_data(data)
 
     def _push_data(self, data):
@@ -439,6 +466,28 @@ def _push_data(self, data):
         self.add_list_items(arrays)
         self._listwidget.setCurrentRow(0)
 
+    def on_stack_frame_changed(self):
+        selected = self._stack_frame_widget.selectedItems()
+        if selected:
+            assert len(selected) == 1
+            selected_item = selected[0]
+            assert isinstance(selected_item, QListWidgetItem)
+
+            frame_summary = selected_item.data(Qt.UserRole)
+            frame_globals, frame_locals = frame_summary.globals, frame_summary.locals
+            data = collections.OrderedDict()
+            data.update([(k, frame_globals[k]) for k in sorted(frame_globals.keys())])
+            data.update([(k, frame_locals[k]) for k in sorted(frame_locals.keys())])
+
+            # CHECK:
+            # * This clears the undo/redo stack, which is safer but is not ideal.
+            #   When inspecting, for all frames except the last one the editor should be readonly (we should allow
+            #   creating new temporary variables but not change existing ones).
+            # * Does changing the last frame values has any effect after quitting the editor?
+            #   It would be nice if we could do that (possibly with a warning when quitting the debug window)
+            self._reset()
+            self._push_data(data)
+
     def _reset(self):
         self.data = la.Session()
         self._listwidget.clear()
@@ -521,9 +570,9 @@ def add_list_items(self, names):
 
     def delete_list_item(self, to_delete):
         deleted_items = self._listwidget.findItems(to_delete, Qt.MatchExactly)
-        assert len(deleted_items) == 1
-        deleted_item_idx = self._listwidget.row(deleted_items[0])
-        self._listwidget.takeItem(deleted_item_idx)
+        if len(deleted_items) == 1:
+            deleted_item_idx = self._listwidget.row(deleted_items[0])
+            self._listwidget.takeItem(deleted_item_idx)
 
     def select_list_item(self, to_display):
         changed_items = self._listwidget.findItems(to_display, Qt.MatchExactly)
@@ -644,7 +693,7 @@ def ipython_cell_executed(self):
                 # last command. Which means that if the last command did not produce any output, _ is not modified.
                 cur_output = user_ns['_oh'].get(cur_input_num)
                 if cur_output is not None:
-                    if self._display_in_grid('_', cur_output):
+                    if self._display_in_grid('<expr>', cur_output):
                         self.view_expr(cur_output)
 
                     if isinstance(cur_output, collections.Iterable):
diff --git a/larray_editor/tests/test_api_larray.py b/larray_editor/tests/test_api_larray.py
@@ -10,7 +10,6 @@
 from larray_editor.api import *
 from larray_editor.utils import logger
 
-
 logger.setLevel(logging.DEBUG)
 
 lipro = la.Axis(['P%02d' % i for i in range(1, 16)], 'lipro')
@@ -126,6 +125,7 @@ def make_demo(width=20, ball_radius=5, path_radius=5, steps=30):
 # import cProfile as profile
 # profile.runctx('edit(Session(arr2=arr2))', vars(), {},
 #                'c:\\tmp\\edit.profile')
+debug()
 edit()
 # edit(ses)
 # edit(file)
@@ -170,3 +170,13 @@ def make_demo(width=20, ball_radius=5, path_radius=5, steps=30):
 arr2 = 2 * arr1
 arr3 = la.where(arr1 % 2 == 0, arr1, -arr1)
 compare(arr1, arr2, arr3, bg_gradient='blue-red')
+
+
+def test_run_editor_on_exception(local_arr1):
+    return arr2['my_invalid_key']
+
+run_editor_on_exception()
+# run_editor_on_exception(usercode_traceback=False)
+# run_editor_on_exception(usercode_traceback=False, usercode_frame=False)
+
+test_run_editor_on_exception(arr1)
diff --git a/larray_editor/traceback_tools.py b/larray_editor/traceback_tools.py
