Description
Bug report
Bug description:
Description
I have encountered a potential memory leak in Tkinter that occurs when dynamically generated widgets are frequently updated. Specifically, the issue arises when tk.StringVar is used to display and update text in labels. When the displayed text is rapidly and frequently changed, the memory consumption steadily grows without being released.
Details:
The problem manifests in applications where widgets are dynamically created and destroyed while being continuously updated with new values. In my specific case, tk.StringVar objects are used to control the text of labels. Each label is dynamically generated in a loop, displayed, and then destroyed to make room for new labels.
Even though the widgets are properly destroyed, the memory usage remains high and continues to increase as the StringVar objects are updated frequently.
System Information:
- Operating System: Windows 10 (64-bit)
- Python Version: 3.10.0 (in a Conda environment)
- Tkinter Version: Standard version shipped with Python 3.10
Minimal Reproduction Example
Here is a minimal Python script that reliably reproduces the issue:
import tkinter as tk
import threading
import time
class MemoryLeakDemo:
def __init__(self, master):
self.master = master
self.master.title("Memory Leak Demo")
# Set a fixed window size
self.master.geometry("400x300") # Width x Height
# Create a scrollable frame
self.canvas = tk.Canvas(self.master)
self.scrollbar = tk.Scrollbar(self.master, orient="vertical", command=self.canvas.yview)
self.scrollable_frame = tk.Frame(self.canvas)
self.scrollable_frame.bind(
"<Configure>",
lambda e: self.canvas.configure(
scrollregion=self.canvas.bbox("all")
)
)
self.canvas.create_window((0, 0), window=self.scrollable_frame, anchor="nw")
self.canvas.configure(yscrollcommand=self.scrollbar.set)
self.canvas.pack(side="left", fill="both", expand=True)
self.scrollbar.pack(side="right", fill="y")
# Button to start the dynamic updates
self.start_button = tk.Button(self.scrollable_frame, text="Start Dynamic Updates", command=self.start_dynamic_updates)
self.start_button.pack(pady=10)
self.stop_button = tk.Button(self.scrollable_frame, text="Stop Dynamic Updates", command=self.stop_dynamic_updates)
self.stop_button.pack(pady=10)
self.labels = []
self.running = False
self.update_thread = None
def start_dynamic_updates(self):
if not self.running:
self.running = True
self.update_thread = threading.Thread(target=self.dynamic_update)
self.update_thread.start()
def dynamic_update(self):
"""
Simulates dynamically creating and destroying widgets with StringVar updates.
"""
while self.running:
# Clear previous labels (simulating dynamic removal)
for label in self.labels:
label.destroy()
self.labels.clear()
# Create new labels with StringVars
for i in range(10):
text_var = tk.StringVar()
text_var.set(f"Dynamic Label {i}: {time.time()}")
label = tk.Label(self.scrollable_frame, textvariable=text_var)
label.pack()
self.labels.append(label)
# Simulate rapid updates
time.sleep(0.05)
def stop_dynamic_updates(self):
self.running = False
if self.update_thread:
self.update_thread.join()
def on_close(self):
self.stop_dynamic_updates()
self.master.destroy()
if __name__ == "__main__":
root = tk.Tk()
app = MemoryLeakDemo(root)
root.protocol("WM_DELETE_WINDOW", app.on_close)
root.mainloop()Steps to Reproduce:
- Run the script above.
- Click "Start Dynamic Updates."
- Monitor the application's memory usage over time. You should observe a steady increase in memory consumption, even though the dynamically generated widgets are being destroyed and removed.
Expected Behavior:
The memory should remain stable when widgets are dynamically removed and recreated.
Actual Behavior:
The memory usage continuously increases, indicating a potential memory leak.
Possible Cause:
It appears that tk.StringVar objects, when frequently updated and dynamically assigned, are not being properly released when the widgets are destroyed.
Additional Notes:
The issue is more pronounced when updates happen in very short intervals (e.g., every 50 milliseconds) while widgets are being dynamically created and destroyed.
CPython versions tested on:
3.10
Operating systems tested on:
Windows