gh-81949: IDLE: show help(object) output in a text viewing window

Lib/idlelib/pyshell.py

@@ -938,11 +938,9 @@ def __init__(self, flist=None):
             sys.stderr = self.stderr
             sys.stdin = self.stdin
         try:
-            # page help() text to shell.
-            import pydoc # import must be done here to capture i/o rebinding.
-            # XXX KBK 27Dec07 use text viewer someday, but must work w/o subproc
-            pydoc.pager = pydoc.plainpager
-        except:
+            import pydoc  # import must be done here to capture i/o rebinding.
+            pydoc.pager = self.pager
+        except Exception:
             sys.stderr = sys.__stderr__
             raise
         #
@@ -984,6 +982,16 @@ def replace_event(self, event):
         replace.replace(self.text, insert_tags="stdin")
         return "break"
 
+    def pager(self, text):
+        """pydoc.pager compatible callback for showing help() output."""
+        import pydoc  # Import here to avoid i/o binding issues.
+        text = pydoc.plain(text)  # Remove fancy pydoc formatting.
+        try:
+            title, text = text.split(':\n\n', 1)
+        except ValueError:
+            title = "Help"
+        view_text(self.text, title, text, modal=False)
+
     def get_standard_extension_names(self):
         return idleConf.GetExtensions(shell_only=True)
 

Lib/idlelib/run.py

@@ -530,9 +530,8 @@ def handle(self):
                                    iomenu.encoding, "backslashreplace")
 
         sys.displayhook = rpc.displayhook
-        # page help() text to shell.
-        import pydoc # import must be done here to capture i/o binding
-        pydoc.pager = pydoc.plainpager
+        import pydoc  # import must be done here to capture i/o binding
+        pydoc.pager = self.console.pager
 
         # Keep a reference to stdin so that it won't try to exit IDLE if
         # sys.stdin gets changed from within IDLE's shell. See issue17838.

Misc/NEWS.d/next/IDLE/2019-08-05-23-58-03.bpo-37768.dM-QL8.rst

@@ -0,0 +1,2 @@
+``help(object)`` now shows the help text in a separate text viewing window
+rather than in the shell output.