[PATCH v2] Require Python 3.4

[Tom Tromey <tromey@adacore.com>]

I believe we previously agreed that the minimum supported Python
version should be 3.4.  This patch makes this change, harmonizing the
documentation (which was inconsistent about the minimum version) and
the code.

New in v2: rebased, and removed a pre-3.4 workaround from __init__.py.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-by: Kevin Buettner <kevinb@redhat.com>
Acked-By: Tom de Vries <tdevries@suse.de>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31870
---
 gdb/NEWS                       |  2 ++
 gdb/README                     |  2 +-
 gdb/configure                  |  4 ++--
 gdb/configure.ac               |  4 ++--
 gdb/doc/gdb.texinfo            |  2 +-
 gdb/python/lib/gdb/__init__.py |  7 +------
 gdb/python/py-gdb-readline.c   |  4 ----
 gdb/python/python-internal.h   | 13 ++-----------
 8 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 2e48a00df5a..970a527a64c 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -124,6 +124,8 @@ info threads [-gid] [-stopped] [-running] [ID]...
 
 * Python API
 
+  ** GDB no longer supports Python versions less than 3.4.
+
   ** New class gdb.Color for dealing with colors.
 
   ** New constant gdb.PARAM_COLOR represents color type of a
diff --git a/gdb/README b/gdb/README
index 5a0030511d6..3c42936b679 100644
--- a/gdb/README
+++ b/gdb/README
@@ -533,7 +533,7 @@ more obscure GDB `configure' options are not listed here.
      GDB scripting much more powerful than the restricted CLI
      scripting language.  If your host does not have Python installed,
      you can find it on `http://www.python.org/download/'.  The oldest
-     version of Python supported by GDB is 3.2.  The optional argument
+     version of Python supported by GDB is 3.4.  The optional argument
      PYTHON is used to find the Python headers and libraries.  It can
      be either the name of a Python executable, or the name of the
      directory in which Python is installed.
diff --git a/gdb/configure b/gdb/configure
index 683fcaef9fe..b34f66679e8 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -28167,8 +28167,8 @@ int
 main ()
 {
 
-				    #if PY_MAJOR_VERSION != 3
-				    # error "We only support Python 3"
+				    #if PY_VERSION_HEX < 0x03040000
+				    # error "Minimum supported Python version is 3.4"
 				    #endif
 				    Py_Initialize ();
 
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 052d0319a04..9529e850154 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -740,8 +740,8 @@ AC_DEFUN([AC_TRY_LIBPYTHON],
   found_usable_python=no
   AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include "Python.h"]],
                                  [[
-				    #if PY_MAJOR_VERSION != 3
-				    # error "We only support Python 3"
+				    #if PY_VERSION_HEX < 0x03040000
+				    # error "Minimum supported Python version is 3.4"
 				    #endif
 				    Py_Initialize ();
 				 ]])],
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 05f550233fe..267647108dd 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -41466,7 +41466,7 @@ libpython is present and found at configure time.)  Python makes
 @value{GDBN} scripting much more powerful than the restricted CLI
 scripting language.  If your host does not have Python installed, you
 can find it on @url{http://www.python.org/download/}.  The oldest version
-of Python supported by GDB is 3.0.1.  The optional argument @var{python}
+of Python supported by GDB is 3.4.  The optional argument @var{python}
 is used to find the Python headers and libraries.  It can be either
 the name of a Python executable, or the name of the directory in which
 Python is installed.
diff --git a/gdb/python/lib/gdb/__init__.py b/gdb/python/lib/gdb/__init__.py
index 69c15b16d87..03eb426b662 100644
--- a/gdb/python/lib/gdb/__init__.py
+++ b/gdb/python/lib/gdb/__init__.py
@@ -19,12 +19,7 @@ import sys
 import threading
 import traceback
 from contextlib import contextmanager
-
-# Python 3 moved "reload"
-if sys.version_info >= (3, 4):
-    from importlib import reload
-else:
-    from imp import reload
+from importlib import reload
 
 import _gdb
 
diff --git a/gdb/python/py-gdb-readline.c b/gdb/python/py-gdb-readline.c
index ea3a3850312..70ceebb36a1 100644
--- a/gdb/python/py-gdb-readline.c
+++ b/gdb/python/py-gdb-readline.c
@@ -29,11 +29,7 @@
 
 static char *
 gdbpy_readline_wrapper (FILE *sys_stdin, FILE *sys_stdout,
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 4
 			const char *prompt)
-#else
-			char *prompt)
-#endif
 {
   int n;
   const char *p = NULL;
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 5262d767529..bdccb265441 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -88,6 +88,8 @@
 #include <frameobject.h>
 #include "py-ref.h"
 
+static_assert (PY_VERSION_HEX >= 0x03040000);
+
 #define Py_TPFLAGS_CHECKTYPES 0
 
 /* If Python.h does not define WITH_THREAD, then the various
@@ -135,17 +137,6 @@ typedef unsigned long gdb_py_ulongest;
 
 #endif /* HAVE_LONG_LONG */
 
-#if PY_VERSION_HEX < 0x03020000
-typedef long Py_hash_t;
-#endif
-
-/* PyMem_RawMalloc appeared in Python 3.4.  For earlier versions, we can just
-   fall back to PyMem_Malloc.  */
-
-#if PY_VERSION_HEX < 0x03040000
-#define PyMem_RawMalloc PyMem_Malloc
-#endif
-
 /* A template variable holding the format character (as for
    Py_BuildValue) for a given type.  */
 template<typename T>

base-commit: 2490dbf4e484616e6aecf3c57efcd17a819fae5b
-- 
2.49.0