Implement an idea by Paul Rubin:
Change pickling format for bools to use a backwards compatible
encoding. This means you can pickle True or False on Python 2.3
and Python 2.2 or before will read it back as 1 or 0. The code
used for pickling bools before would create pickles that could
not be read in previous Python versions.
diff --git a/Lib/pickle.py b/Lib/pickle.py
index 96ee5c1..541624a 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -101,8 +101,8 @@
EMPTY_TUPLE = ')'
SETITEMS = 'u'
BINFLOAT = 'G'
-TRUE = 'Z'
-FALSE = 'z'
+TRUE = 'I01\n'
+FALSE = 'I00\n'
__all__.extend([x for x in dir() if re.match("[A-Z][A-Z0-9_]+$",x)])
@@ -639,20 +639,18 @@
self.append(None)
dispatch[NONE] = load_none
- def load_false(self):
- self.append(False)
- dispatch[FALSE] = load_false
-
- def load_true(self):
- self.append(True)
- dispatch[TRUE] = load_true
-
def load_int(self):
data = self.readline()
- try:
- self.append(int(data))
- except ValueError:
- self.append(long(data))
+ if data == FALSE[1:]:
+ val = False
+ elif data == TRUE[1:]:
+ val = True
+ else:
+ try:
+ val = int(data)
+ except ValueError:
+ val = long(data)
+ self.append(val)
dispatch[INT] = load_int
def load_binint(self):
diff --git a/Lib/test/test_bool.py b/Lib/test/test_bool.py
index ee5d5fa..0a60a3b 100644
--- a/Lib/test/test_bool.py
+++ b/Lib/test/test_bool.py
@@ -224,5 +224,11 @@
veris(cPickle.loads(pickle.dumps(True)), True)
veris(cPickle.loads(pickle.dumps(False)), False)
+# Test for specific backwards-compatible pickle values
+vereq(pickle.dumps(True), "I01\n.")
+vereq(pickle.dumps(False), "I00\n.")
+vereq(cPickle.dumps(True), "I01\n.")
+vereq(cPickle.dumps(False), "I00\n.")
+
if verbose:
print "All OK"
diff --git a/Modules/cPickle.c b/Modules/cPickle.c
index 9871627..a99d69f 100644
--- a/Modules/cPickle.c
+++ b/Modules/cPickle.c
@@ -77,8 +77,8 @@
#define TUPLE 't'
#define EMPTY_TUPLE ')'
#define SETITEMS 'u'
-#define TRUE 'Z'
-#define FALSE 'z'
+#define TRUE "I01\n"
+#define FALSE "I00\n"
static char MARKv = MARK;
@@ -936,10 +936,11 @@
static int
save_bool(Picklerobject *self, PyObject *args)
{
- static char buf[2] = {FALSE, TRUE};
+ static char *buf[2] = {FALSE, TRUE};
+ static char len[2] = {sizeof(FALSE)-1, sizeof(TRUE)-1};
long l = PyInt_AS_LONG((PyIntObject *)args);
- if ((*self->write_func)(self, buf + l, 1) < 0)
+ if ((*self->write_func)(self, buf[l], len[l]) < 0)
return -1;
return 0;
@@ -2655,7 +2656,12 @@
}
}
else {
- if (!( py_int = PyInt_FromLong(l))) goto finally;
+ if (len == 3 && (l == 0 || l == 1)) {
+ if (!( py_int = PyBool_FromLong(l))) goto finally;
+ }
+ else {
+ if (!( py_int = PyInt_FromLong(l))) goto finally;
+ }
}
free(s);
@@ -3763,16 +3769,6 @@
break;
continue;
- case FALSE:
- if (load_false(self) < 0)
- break;
- continue;
-
- case TRUE:
- if (load_true(self) < 0)
- break;
- continue;
-
case BININT:
if (load_binint(self) < 0)
break;