gh-102832: IDLE - remove use of deprecated sys.last_xyzs for stackviewer (#103339)

iritkatriel · web-flow · commit 3ee921d84f06 · 2023-06-08T21:19:05.000+01:00
diff --git a/Lib/idlelib/idle_test/test_stackviewer.py b/Lib/idlelib/idle_test/test_stackviewer.py
@@ -6,28 +6,19 @@
 from tkinter import Tk
 
 from idlelib.tree import TreeNode, ScrolledCanvas
-import sys
 
 
 class StackBrowserTest(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        svs = stackviewer.sys
-        try:
-            abc
-        except NameError:
-            svs.last_type, svs.last_value, svs.last_traceback = (
-                sys.exc_info())
 
         requires('gui')
         cls.root = Tk()
         cls.root.withdraw()
 
     @classmethod
     def tearDownClass(cls):
-        svs = stackviewer.sys
-        del svs.last_traceback, svs.last_type, svs.last_value
 
         cls.root.update_idletasks()
 ##        for id in cls.root.tk.call('after', 'info'):
@@ -36,7 +27,10 @@ def tearDownClass(cls):
         del cls.root
 
     def test_init(self):
-        sb = stackviewer.StackBrowser(self.root)
+        try:
+            abc
+        except NameError as exc:
+            sb = stackviewer.StackBrowser(self.root, exc)
         isi = self.assertIsInstance
         isi(stackviewer.sc, ScrolledCanvas)
         isi(stackviewer.item, stackviewer.StackTreeItem)
diff --git a/Lib/idlelib/pyshell.py b/Lib/idlelib/pyshell.py
@@ -1363,19 +1363,19 @@ def runit(self):
                 self.text.tag_remove(self.user_input_insert_tags, index_before)
             self.shell_sidebar.update_sidebar()
 
-    def open_stack_viewer(self, event=None):
+    def open_stack_viewer(self, event=None):  # -n mode only
         if self.interp.rpcclt:
             return self.interp.remote_stack_viewer()
+
+        from idlelib.stackviewer import StackBrowser
         try:
-            sys.last_traceback
+            StackBrowser(self.root, sys.last_value, self.flist)
         except:
             messagebox.showerror("No stack trace",
                 "There is no stack trace yet.\n"
-                "(sys.last_traceback is not defined)",
+                "(sys.last_value is not defined)",
                 parent=self.text)
-            return
-        from idlelib.stackviewer import StackBrowser
-        StackBrowser(self.root, self.flist)
+        return None
 
     def view_restart_mark(self, event=None):
         self.text.see("iomark")
diff --git a/Lib/idlelib/run.py b/Lib/idlelib/run.py
@@ -622,17 +622,16 @@ def get_the_completion_list(self, what, mode):
 
     def stackviewer(self, flist_oid=None):
         if self.user_exc_info:
-            typ, val, tb = self.user_exc_info
+            _, exc, tb = self.user_exc_info
         else:
             return None
         flist = None
         if flist_oid is not None:
             flist = self.rpchandler.get_remote_proxy(flist_oid)
         while tb and tb.tb_frame.f_globals["__name__"] in ["rpc", "run"]:
             tb = tb.tb_next
-        sys.last_type = typ
-        sys.last_value = val
-        item = stackviewer.StackTreeItem(flist, tb)
+        exc.__traceback__ = tb
+        item = stackviewer.StackTreeItem(exc, flist)
         return debugobj_r.remote_object_tree_item(item)
 
 
diff --git a/Lib/idlelib/stackviewer.py b/Lib/idlelib/stackviewer.py
@@ -1,33 +1,30 @@
 import linecache
 import os
-import sys
 
 import tkinter as tk
 
 from idlelib.debugobj import ObjectTreeItem, make_objecttreeitem
 from idlelib.tree import TreeNode, TreeItem, ScrolledCanvas
 
-def StackBrowser(root, flist=None, tb=None, top=None):
+def StackBrowser(root, exc, flist=None, top=None):
     global sc, item, node  # For testing.
     if top is None:
         top = tk.Toplevel(root)
     sc = ScrolledCanvas(top, bg="white", highlightthickness=0)
     sc.frame.pack(expand=1, fill="both")
-    item = StackTreeItem(flist, tb)
+    item = StackTreeItem(exc, flist)
     node = TreeNode(sc.canvas, None, item)
     node.expand()
 
 
 class StackTreeItem(TreeItem):
 
-    def __init__(self, flist=None, tb=None):
+    def __init__(self, exc, flist=None):
         self.flist = flist
-        self.stack = self.get_stack(tb)
-        self.text = self.get_exception()
+        self.stack = self.get_stack(None if exc is None else exc.__traceback__)
+        self.text = f"{type(exc).__name__}: {str(exc)}"
 
     def get_stack(self, tb):
-        if tb is None:
-            tb = sys.last_traceback
         stack = []
         if tb and tb.tb_frame is None:
             tb = tb.tb_next
@@ -36,17 +33,7 @@ def get_stack(self, tb):
             tb = tb.tb_next
         return stack
 
-    def get_exception(self):
-        type = sys.last_type
-        value = sys.last_value
-        if hasattr(type, "__name__"):
-            type = type.__name__
-        s = str(type)
-        if value is not None:
-            s = s + ": " + str(value)
-        return s
-
-    def GetText(self):
+    def GetText(self):  # Titlecase names are overrides.
         return self.text
 
     def GetSubList(self):
@@ -133,19 +120,9 @@ def _stack_viewer(parent):  # htest #
     flist = PyShellFileList(top)
     try: # to obtain a traceback object
         intentional_name_error
-    except NameError:
-        exc_type, exc_value, exc_tb = sys.exc_info()
-    # inject stack trace to sys
-    sys.last_type = exc_type
-    sys.last_value = exc_value
-    sys.last_traceback = exc_tb
-
-    StackBrowser(top, flist=flist, top=top, tb=exc_tb)
-
-    # restore sys to original state
-    del sys.last_type
-    del sys.last_value
-    del sys.last_traceback
+    except NameError as e:
+        StackBrowser(top, e, flist=flist, top=top)
+
 
 if __name__ == '__main__':
     from unittest import main
