replace shell sidebar prompt and input line recognition method

Prompts are now marked in the text by adding the "console" tag to
the newline character ('\n') before the beginning of the line.  This
works around issues with the prompt itself usually no longer being
written in the text widget.

With another small fix to the PyShell.recall() method, input lines
can now be recognized consistently by checking for the "stdin" tag.

This is much better than attempting to separately track the prompt
and input lines, since those are difficult to keep up to date after
undo/redo actions and squeezing/unsqueezing of previous output.

Lib/idlelib/pyshell.py

@@ -48,6 +48,7 @@
 
 from idlelib.colorizer import ColorDelegator
 from idlelib.config import idleConf
+from idlelib.delegator import Delegator
 from idlelib import debugger
 from idlelib import debugger_r
 from idlelib.editor import EditorWindow, fixwordbreaks
@@ -367,6 +368,14 @@ def delete(self, index1, index2=None):
         UndoDelegator.delete(self, index1, index2)
 
 
+class UserInputTaggingDelegator(Delegator):
+    """Delegator used to tag user input with "stdin"."""
+    def insert(self, index, chars, tags=None):
+        if tags is None:
+            tags = "stdin"
+        self.delegate.insert(index, chars, tags)
+
+
 class MyRPCClient(rpc.RPCClient):
 
     def handle_EOF(self):
@@ -912,12 +921,15 @@ def __init__(self, flist=None):
         #
         self.pollinterval = 50  # millisec
 
-        self.input_lines = set()
-        self.prompt_lines = set()
-
         self.shell_sidebar = self.ShellSidebar(self)
         self.shell_sidebar.show_sidebar()
 
+        # Insert UserInputTaggingDelegator at the top of the percolator,
+        # but make calls to text.insert() skip it.  This causes only insert
+        # events generated in Tcl/Tk to go through this delegator.
+        self.text.insert = self.per.top.insert
+        self.per.insertfilter(UserInputTaggingDelegator())
+
     def get_tag_colors(self):
         tag_colors = super().get_tag_colors()
 
@@ -1169,7 +1181,7 @@ def enter_callback(self, event):
             if prev and self.text.compare("insert", "<", prev[1]):
                 for line in reversed(range(self.getlineno(prev[0]),
                                            self.getlineno(prev[1]))):
-                    if line in self.prompt_lines:
+                    if "console" in self.text.tag_names(f"{line}.0-1c"):
                         break
                 if self.text.compare(f"{line}.0", ">", prev[0]):
                     prev = (f"{line}.0", prev[1])
@@ -1179,7 +1191,7 @@ def enter_callback(self, event):
             if next and self.text.compare("insert lineend", ">=", next[0]):
                 for line in range(self.getlineno(next[0]),
                                   self.getlineno(next[1])):
-                    if line + 1 in self.prompt_lines:
+                    if "console" in self.text.tag_names(f"{line+1}.0-1c"):
                         break
                 if self.text.compare(f"{line}.end", "<", next[1]):
                     next = (next[0], f"{line}.end")
@@ -1236,17 +1248,15 @@ def recall(self, s, event):
                 self.newline_and_indent_event(event)
                 prefix = self.text.get("insert linestart", "insert")
             first_line = self.getlineno("insert")
-            self.text.insert("insert", lines[0].strip())
+            self.text.insert("insert", lines[0].strip(), "stdin")
             if len(lines) > 1:
                 orig_base_indent = re.search(r'^([ \t]*)', lines[0]).group(0)
                 new_base_indent  = re.search(r'^([ \t]*)', prefix).group(0)
                 for line in lines[1:]:
                     if line.startswith(orig_base_indent):
                         # replace orig base indentation with new indentation
                         line = new_base_indent + line[len(orig_base_indent):]
-                    self.text.insert('insert', '\n'+line.rstrip())
-            self.input_lines.update(
-                range(first_line, self.getlineno("insert") + 1))
+                    self.text.insert('insert', '\n'+line.rstrip(), "stdin")
             self.shell_sidebar.update_sidebar()
         finally:
             self.text.see("insert")
@@ -1268,8 +1278,6 @@ def runit(self):
         # If the input is a complete statement, the sidebar updates will be
         # handled elsewhere.
         if input_is_incomplete:
-            self.input_lines.update(range(self.getlineno("iomark"),
-                                          self.getlineno("end-1c") + 1))
             self.shell_sidebar.update_sidebar()
 
     def open_stack_viewer(self, event=None):
@@ -1297,17 +1305,12 @@ def restart_shell(self, event=None):
     def showprompt(self):
         self.resetoutput()
 
-        prompt_lineno = self.getlineno("iomark")
         prompt = self.prompt
         if self.sys_ps1 and prompt.endswith(self.sys_ps1):
             prompt = prompt[:-len(self.sys_ps1)]
+        self.text.tag_add("console", "iomark-1c")
         self.console.write(prompt)
 
-        n_prompt_lines = prompt.count('\n') + 1
-        self.prompt_lines.update(
-            range(prompt_lineno, prompt_lineno + n_prompt_lines))
-        self.shell_sidebar.update_sidebar()
-
         self.text.mark_set("insert", "end-1c")
         self.set_line_and_column()
         self.io.reset_undo()

Lib/idlelib/sidebar.py

@@ -478,6 +478,7 @@ def change_callback(self):
 
     def update_sidebar(self):
         text = self.text
+        text_tagnames = text.tag_names
         canvas = self.canvas
 
         canvas.delete(tk.ALL)
@@ -488,10 +489,11 @@ def update_sidebar(self):
             if lineinfo is None:
                 break
             y = lineinfo[1]
-            lineno = self.editwin.getlineno(index)
+            is_prompt = "console" in text_tagnames(f"{index} linestart -1c")
+            is_input = "stdin" in text_tagnames(f"{index} lineend -1c")
             prompt = (
-                '>>>' if lineno in self.editwin.prompt_lines else
-                '...' if lineno in self.editwin.input_lines else
+                '>>>' if is_prompt else
+                '...' if is_input else
                 '   '
             )
             canvas.create_text(2, y, anchor=tk.NW, text=prompt,