18764: remove the problematic 'print' alias for the PDB 'p' command.

So that it no longer shadows the print function.

Patch by Connor Osborn, doc and test changes by R. David Murray.

5 files changed, 31 insertions, 11 deletions

diff --git a/Doc/library/pdb.rst b/Doc/library/pdb.rst
index f4e37ac..66a78d0 100644
--- a/Doc/library/pdb.rst
+++ b/Doc/library/pdb.rst
@@ -41,7 +41,7 @@ of the debugger is::
 .. versionchanged:: 3.3
    Tab-completion via the :mod:`readline` module is available for commands and
    command arguments, e.g. the current global and local names are offered as
-   arguments of the ``print`` command.
+   arguments of the ``p`` command.
 
 :file:`pdb.py` can also be invoked as a script to debug other scripts.  For
 example::
@@ -309,7 +309,7 @@ by the local file.
    ``end`` to terminate the commands. An example::
 
       (Pdb) commands 1
-      (com) print some_variable
+      (com) p some_variable
       (com) end
       (Pdb)
 
@@ -409,7 +409,7 @@ by the local file.
 
 .. pdbcommand:: pp expression
 
-   Like the :pdbcmd:`print` command, except the value of the expression is
+   Like the :pdbcmd:`p` command, except the value of the expression is
    pretty-printed using the :mod:`pprint` module.
 
 .. pdbcommand:: whatis expression
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
index ed4ea17..373f8de 100644
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -302,6 +302,22 @@ descriptors or a Windows handle:
 * :func:`os.get_handle_inheritable`, :func:`os.set_handle_inheritable`
 
 
+pdb
+---
+
+The ``print`` command has been removed from :mod:`pdb`, restoring access to the
+``print`` function.
+
+Rationale: Python2's ``pdb`` did not have a ``print`` command; instead,
+entering ``print`` executed the ``print`` statement.  In Python3 ``print`` was
+mistakenly made an alias for the pdb :pdbcmd:`p` command.  ``p``, however,
+prints the ``repr`` of its argument, not the ``str`` like the Python2 ``print``
+command did.  Worse, the Python3 ``pdb print`` command shadowed the Python3
+``print`` function, making it inaccessible at the ``pdb`` prompt.
+
+(Contributed by Connor Osborn in :issue:`18764`.)
+
+
 poplib
 ------
 
diff --git a/Lib/pdb.py b/Lib/pdb.py
index 45fe477..1ec83da 100755
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -1159,15 +1159,13 @@ class Pdb(bdb.Bdb, cmd.Cmd):
             return _rstr('** raised %s **' % err)
 
     def do_p(self, arg):
-        """p(rint) expression
+        """p expression
         Print the value of the expression.
         """
         try:
             self.message(repr(self._getval(arg)))
         except:
             pass
-    # make "print" an alias of "p" since print isn't a Python statement anymore
-    do_print = do_p
 
     def do_pp(self, arg):
         """pp expression
@@ -1388,7 +1386,7 @@ class Pdb(bdb.Bdb, cmd.Cmd):
         placed in the .pdbrc file):
 
         # Print instance variables (usage "pi classInst")
-        alias pi for k in %1.__dict__.keys(): print "%1.",k,"=",%1.__dict__[k]
+        alias pi for k in %1.__dict__.keys(): print("%1.",k,"=",%1.__dict__[k])
         # Print instance variables in self
         alias ps pi self
         """
@@ -1546,7 +1544,7 @@ if __doc__ is not None:
         'help', 'where', 'down', 'up', 'break', 'tbreak', 'clear', 'disable',
         'enable', 'ignore', 'condition', 'commands', 'step', 'next', 'until',
         'jump', 'return', 'retval', 'run', 'continue', 'list', 'longlist',
-        'args', 'print', 'pp', 'whatis', 'source', 'display', 'undisplay',
+        'args', 'p', 'pp', 'whatis', 'source', 'display', 'undisplay',
         'interact', 'alias', 'unalias', 'debug', 'quit',
     ]
 
diff --git a/Lib/test/test_pdb.py b/Lib/test/test_pdb.py
index 0babaa0..e17f933 100644
--- a/Lib/test/test_pdb.py
+++ b/Lib/test/test_pdb.py
@@ -205,7 +205,8 @@ def test_pdb_breakpoint_commands():
     ...     'enable 1',
     ...     'clear 1',
     ...     'commands 2',
-    ...     'print 42',
+    ...     'p "42"',
+    ...     'print("42", 7*6)',     # Issue 18764 (not about breakpoints)
     ...     'end',
     ...     'continue',  # will stop at breakpoint 2 (line 4)
     ...     'clear',     # clear all!
@@ -252,11 +253,13 @@ def test_pdb_breakpoint_commands():
     (Pdb) clear 1
     Deleted breakpoint 1 at <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>:3
     (Pdb) commands 2
-    (com) print 42
+    (com) p "42"
+    (com) print("42", 7*6)
     (com) end
     (Pdb) continue
     1
-    42
+    '42'
+    42 42
     > <doctest test.test_pdb.test_pdb_breakpoint_commands[0]>(4)test_function()
     -> print(2)
     (Pdb) clear
diff --git a/Misc/NEWS b/Misc/NEWS
index 3044d85..ab9cea7 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -34,6 +34,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #18764: remove the 'print' alias for the PDB 'p' command so that it no
+  longer shadows the print function.
+
 - Issue #19158:  a rare race in BoundedSemaphore could allow .release() too
   often.