Memory leak when closing editor or console tabs

[impact27]

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

Every time a tab is closed, the code editor is not removed from memory.
The full list of added object can be seen here: (Executed in the internal console)

>>> objgraph.show_growth(limit=1000)
tuple                         37021      +120
dict                          68206       +58
QShortcut                       280       +42
Shortcut                        254       +42
list                          74018       +38
method                         1774       +32
cell                          12439       +26
QColor                          247       +26
function                      63060       +24
SpyderAction                    559       +23
weakref                       12590       +21
QTimer                          105       +16
QTextBlock                      498       +10
QTextCharFormat                  86        +9
QBrush                           28        +7
QPen                             28        +7
QAction                         162        +5
set                            4836        +3
QMutex                           15        +3
FoldingRegion                   344        +3
partial                         694        +2
QMenu                            22        +2
QComboBox                        10        +2
QTextCursor                      12        +2
QScrollBar                       12        +2
IntervalTree                      9        +2
QStaticText                       8        +2
SortedDict                        9        +2
SortedList                        9        +2
builtin_function_or_method     5421        +1
Signals                          35        +1
Context                          37        +1
diff_match_patch                  6        +1
Property                         88        +1
QThread                          13        +1
QWidget                          89        +1
QHBoxLayout                     103        +1
QFont                            24        +1
LineNumberArea                    6        +1
PythonSH                          6        +1
QObject                           6        +1
QTextDocument                     7        +1
QPoint                            6        +1
CallTipWidget                     7        +1
QBasicTimer                       7        +1
ToolTipWidget                     5        +1
TextDecorationsManager            5        +1
CompletionWidget                  7        +1
HTMLDelegate                      5        +1
Future                           13        +1
Handle                           20        +1
QtKillRing                        5        +1
KillRing                          5        +1
CodeEditor                        4        +1
TextHelper                        4        +1
PanelsManager                     4        +1
EdgeLine                          4        +1
IndentationGuide                  4        +1
FoldingPanel                      4        +1
DelayJobRunner                    4        +1
DebuggerManager                   4        +1
DebuggerPanel                     4        +1
ClassFunctionDropdown             4        +1
ScrollFlagArea                    4        +1
DocstringWriterExtension          4        +1
QEventLoop                        4        +1
EditorExtensionsManager           4        +1
SnippetsExtension                 4        +1
CloseBracketsExtension            4        +1
Index                             4        +1
IndexHandle                       4        +1
OutlineExplorerProxyEditor        4        +1
patch_obj                         3        +1
CloseQuotesExtension              4        +1
TextDecoration                    4        +1
PropertyHandle                    4        +1
Node                            357        +1
FoldingStatus                     4        +1
Interval                        496        +1
PythonWorker                      3        +1

A lot of these objects, including LineNumberArea and Shortcut, are linked with CodeEditor. The question is therefore why the code editor is never removed. One can inspect the reference graph with objgraph:

The problem is therefore that the parent of each new CompletionWidget is set to the main window and never removed.
It makes more sense to have the CodeEditor as a parent, but that only displaces the problem, as the new shortest chain is:

CompletionPlugin.requests grows indefinitely.

What steps reproduce the problem?

What is the expected output? What do you see instead?

Paste Traceback/Error Below (if applicable)

PASTE TRACEBACK HERE

Versions

• Spyder version:
• Python version:
• Qt version:
• PyQt version:
• Operating System name/version:

Dependencies

PASTE DEPENDENCIES HERE

[impact27]

I digged a bit more and found two other sources of CodeEditor leaks:
This one is the expected graph, but the CodeEditor is never removed. This can be solved by calling editor.setParent(None) in EditorStack.close_file

The other one shows that the shortcut list (_shortcut_data) is never emptied:

[ccordoba12]

Hey @impact27, thanks a lot for taking a look at these issues! About what you said:

The other one shows that the shortcut list (_shortcut_data) is never emptied:

Is it not be possible to clear that on EditorStack.close_file as well?

[impact27]

• Set CompletionWidget parent to None
• Set CodeEditor parent to None
• Use weakref in requests
• unregister the shortcuts