Issue #4842, patch 1/2: fix pickle in Python 3.x so that pickling with the
'L' opcode always appends an 'L' on output, just as 2.x does.  When
unpickling, remove the trailing 'L' (if present) before passing the
result to PyLong_FromString.
diff --git a/Lib/pickle.py b/Lib/pickle.py
index 2947bd4..409d4b2 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -470,7 +470,7 @@
             else:
                 self.write(LONG4 + pack("<i", n) + encoded)
             return
-        self.write(LONG + repr(obj).encode("ascii") + b'\n')
+        self.write(LONG + repr(obj).encode("ascii") + b'L\n')
     dispatch[int] = save_long
 
     def save_float(self, obj, pack=struct.pack):
@@ -890,6 +890,8 @@
 
     def load_long(self):
         val = self.readline()[:-1].decode("ascii")
+        if val and val[-1] == 'L':
+            val = val[:-1]
         self.append(int(val, 0))
     dispatch[LONG[0]] = load_long
 
diff --git a/Lib/pickletools.py b/Lib/pickletools.py
index 1dd45da..6614df7 100644
--- a/Lib/pickletools.py
+++ b/Lib/pickletools.py
@@ -527,6 +527,8 @@
     """
 
     s = read_stringnl(f, decode=False, stripquotes=False)
+    if s[-1:] == b'L':
+        s = s[:-1]
     return int(s)
 
 
@@ -2052,39 +2054,39 @@
     1: l        LIST       (MARK at 0)
     2: p    PUT        0
     5: L    LONG       1
-    8: a    APPEND
-    9: L    LONG       2
-   12: a    APPEND
-   13: (    MARK
-   14: L        LONG       3
-   17: L        LONG       4
-   20: t        TUPLE      (MARK at 13)
-   21: p    PUT        1
-   24: a    APPEND
-   25: (    MARK
-   26: d        DICT       (MARK at 25)
-   27: p    PUT        2
-   30: c    GLOBAL     'builtins bytes'
-   46: p    PUT        3
-   49: (    MARK
-   50: (        MARK
-   51: l            LIST       (MARK at 50)
-   52: p        PUT        4
-   55: L        LONG       97
-   59: a        APPEND
-   60: L        LONG       98
+    9: a    APPEND
+   10: L    LONG       2
+   14: a    APPEND
+   15: (    MARK
+   16: L        LONG       3
+   20: L        LONG       4
+   24: t        TUPLE      (MARK at 15)
+   25: p    PUT        1
+   28: a    APPEND
+   29: (    MARK
+   30: d        DICT       (MARK at 29)
+   31: p    PUT        2
+   34: c    GLOBAL     'builtins bytes'
+   50: p    PUT        3
+   53: (    MARK
+   54: (        MARK
+   55: l            LIST       (MARK at 54)
+   56: p        PUT        4
+   59: L        LONG       97
    64: a        APPEND
-   65: L        LONG       99
-   69: a        APPEND
-   70: t        TUPLE      (MARK at 49)
-   71: p    PUT        5
-   74: R    REDUCE
-   75: p    PUT        6
-   78: V    UNICODE    'def'
-   83: p    PUT        7
-   86: s    SETITEM
-   87: a    APPEND
-   88: .    STOP
+   65: L        LONG       98
+   70: a        APPEND
+   71: L        LONG       99
+   76: a        APPEND
+   77: t        TUPLE      (MARK at 53)
+   78: p    PUT        5
+   81: R    REDUCE
+   82: p    PUT        6
+   85: V    UNICODE    'def'
+   90: p    PUT        7
+   93: s    SETITEM
+   94: a    APPEND
+   95: .    STOP
 highest protocol among opcodes = 0
 
 Try again with a "binary" pickle.
@@ -2157,12 +2159,12 @@
    92: V    UNICODE    'value'
    99: p    PUT        7
   102: L    LONG       42
-  106: s    SETITEM
-  107: b    BUILD
-  108: a    APPEND
-  109: g    GET        5
-  112: a    APPEND
-  113: .    STOP
+  107: s    SETITEM
+  108: b    BUILD
+  109: a    APPEND
+  110: g    GET        5
+  113: a    APPEND
+  114: .    STOP
 highest protocol among opcodes = 0
 
 >>> dis(pickle.dumps(x, 1))
diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index 887b512..3ed84fb 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -90,21 +90,21 @@
 # the object returned by create_data().
 
 DATA0 = (
-    b'(lp0\nL0\naL1\naF2.0\nac'
+    b'(lp0\nL0L\naL1L\naF2.0\nac'
     b'builtins\ncomplex\n'
     b'p1\n(F3.0\nF0.0\ntp2\nRp'
-    b'3\naL1\naL-1\naL255\naL-'
-    b'255\naL-256\naL65535\na'
-    b'L-65535\naL-65536\naL2'
-    b'147483647\naL-2147483'
-    b'647\naL-2147483648\na('
+    b'3\naL1L\naL-1L\naL255L\naL-'
+    b'255L\naL-256L\naL65535L\na'
+    b'L-65535L\naL-65536L\naL2'
+    b'147483647L\naL-2147483'
+    b'647L\naL-2147483648L\na('
     b'Vabc\np4\ng4\nccopyreg'
     b'\n_reconstructor\np5\n('
     b'c__main__\nC\np6\ncbu'
     b'iltins\nobject\np7\nNt'
     b'p8\nRp9\n(dp10\nVfoo\np1'
-    b'1\nL1\nsVbar\np12\nL2\nsb'
-    b'g9\ntp13\nag13\naL5\na.'
+    b'1\nL1L\nsVbar\np12\nL2L\nsb'
+    b'g9\ntp13\nag13\naL5L\na.'
 )
 
 # Disassembly of DATA0
@@ -113,80 +113,80 @@
     1: l        LIST       (MARK at 0)
     2: p    PUT        0
     5: L    LONG       0
-    8: a    APPEND
-    9: L    LONG       1
-   12: a    APPEND
-   13: F    FLOAT      2.0
-   18: a    APPEND
-   19: c    GLOBAL     'builtins complex'
-   37: p    PUT        1
-   40: (    MARK
-   41: F        FLOAT      3.0
-   46: F        FLOAT      0.0
-   51: t        TUPLE      (MARK at 40)
-   52: p    PUT        2
-   55: R    REDUCE
-   56: p    PUT        3
-   59: a    APPEND
-   60: L    LONG       1
-   63: a    APPEND
-   64: L    LONG       -1
-   68: a    APPEND
-   69: L    LONG       255
-   74: a    APPEND
-   75: L    LONG       -255
-   81: a    APPEND
-   82: L    LONG       -256
-   88: a    APPEND
-   89: L    LONG       65535
-   96: a    APPEND
-   97: L    LONG       -65535
-  105: a    APPEND
-  106: L    LONG       -65536
+    9: a    APPEND
+   10: L    LONG       1
+   14: a    APPEND
+   15: F    FLOAT      2.0
+   20: a    APPEND
+   21: c    GLOBAL     'builtins complex'
+   39: p    PUT        1
+   42: (    MARK
+   43: F        FLOAT      3.0
+   48: F        FLOAT      0.0
+   53: t        TUPLE      (MARK at 42)
+   54: p    PUT        2
+   57: R    REDUCE
+   58: p    PUT        3
+   61: a    APPEND
+   62: L    LONG       1
+   66: a    APPEND
+   67: L    LONG       -1
+   72: a    APPEND
+   73: L    LONG       255
+   79: a    APPEND
+   80: L    LONG       -255
+   87: a    APPEND
+   88: L    LONG       -256
+   95: a    APPEND
+   96: L    LONG       65535
+  104: a    APPEND
+  105: L    LONG       -65535
   114: a    APPEND
-  115: L    LONG       2147483647
-  127: a    APPEND
-  128: L    LONG       -2147483647
-  141: a    APPEND
-  142: L    LONG       -2147483648
-  155: a    APPEND
-  156: (    MARK
-  157: V        UNICODE    'abc'
-  162: p        PUT        4
-  165: g        GET        4
-  168: c        GLOBAL     'copyreg _reconstructor'
-  192: p        PUT        5
-  195: (        MARK
-  196: c            GLOBAL     '__main__ C'
-  208: p            PUT        6
-  211: c            GLOBAL     'builtins object'
-  228: p            PUT        7
-  231: N            NONE
-  232: t            TUPLE      (MARK at 195)
-  233: p        PUT        8
-  236: R        REDUCE
-  237: p        PUT        9
-  240: (        MARK
-  241: d            DICT       (MARK at 240)
-  242: p        PUT        10
-  246: V        UNICODE    'foo'
-  251: p        PUT        11
-  255: L        LONG       1
-  258: s        SETITEM
-  259: V        UNICODE    'bar'
-  264: p        PUT        12
-  268: L        LONG       2
-  271: s        SETITEM
-  272: b        BUILD
-  273: g        GET        9
-  276: t        TUPLE      (MARK at 156)
-  277: p    PUT        13
-  281: a    APPEND
-  282: g    GET        13
-  286: a    APPEND
-  287: L    LONG       5
-  290: a    APPEND
-  291: .    STOP
+  115: L    LONG       -65536
+  124: a    APPEND
+  125: L    LONG       2147483647
+  138: a    APPEND
+  139: L    LONG       -2147483647
+  153: a    APPEND
+  154: L    LONG       -2147483648
+  168: a    APPEND
+  169: (    MARK
+  170: V        UNICODE    'abc'
+  175: p        PUT        4
+  178: g        GET        4
+  181: c        GLOBAL     'copyreg _reconstructor'
+  205: p        PUT        5
+  208: (        MARK
+  209: c            GLOBAL     '__main__ C'
+  221: p            PUT        6
+  224: c            GLOBAL     'builtins object'
+  241: p            PUT        7
+  244: N            NONE
+  245: t            TUPLE      (MARK at 208)
+  246: p        PUT        8
+  249: R        REDUCE
+  250: p        PUT        9
+  253: (        MARK
+  254: d            DICT       (MARK at 253)
+  255: p        PUT        10
+  259: V        UNICODE    'foo'
+  264: p        PUT        11
+  268: L        LONG       1
+  272: s        SETITEM
+  273: V        UNICODE    'bar'
+  278: p        PUT        12
+  282: L        LONG       2
+  286: s        SETITEM
+  287: b        BUILD
+  288: g        GET        9
+  291: t        TUPLE      (MARK at 169)
+  292: p    PUT        13
+  296: a    APPEND
+  297: g    GET        13
+  301: a    APPEND
+  302: L    LONG       5
+  306: a    APPEND
+  307: .    STOP
 highest protocol among opcodes = 0
 """