A tool for inspecting Python pickles¶
AUTHORS:
- Carl Witty (2009-03)
The explain_pickle function takes a pickle and produces Sage code that will evaluate to the contents of the pickle. Ideally, the combination of explain_pickle to produce Sage code and sage_eval to evaluate the code would be a 100% compatible implementation of cPickle’s unpickler; this is almost the case now.
EXAMPLES:
sage: explain_pickle(dumps(12345))
pg_make_integer = unpickle_global('sage.rings.integer', 'make_integer')
pg_make_integer('c1p')
sage: explain_pickle(dumps(polygen(QQ)))
pg_Polynomial_rational_flint = unpickle_global('sage.rings.polynomial.polynomial_rational_flint', 'Polynomial_rational_flint')
pg_PolynomialRing = unpickle_global('sage.rings.polynomial.polynomial_ring_constructor', 'PolynomialRing')
pg_RationalField = unpickle_global('sage.rings.rational_field', 'RationalField')
pg = unpickle_instantiate(pg_RationalField, ())
pg_make_rational = unpickle_global('sage.rings.rational', 'make_rational')
pg_Polynomial_rational_flint(pg_PolynomialRing(pg, 'x', None, False), [pg_make_rational('0'), pg_make_rational('1')], False, True)
sage: sage_eval(explain_pickle(dumps(polygen(QQ)))) == polygen(QQ)
True
By default (as above) the code produced contains calls to several utility functions (unpickle_global, etc.); this is done so that the code is truly equivalent to the pickle. If the pickle can be loaded into a future version of Sage, then the code that explain_pickle produces today should work in that future Sage as well.
It is also possible to produce simpler code, that is tied to the current version of Sage; here are the above two examples again:
sage: explain_pickle(dumps(12345), in_current_sage=True)
from sage.rings.integer import make_integer
make_integer('c1p')
sage: explain_pickle(dumps(polygen(QQ)), in_current_sage=True)
from sage.rings.polynomial.polynomial_rational_flint import Polynomial_rational_flint
from sage.rings.rational import make_rational
Polynomial_rational_flint(PolynomialRing(RationalField(), 'x', None, False), [make_rational('0'), make_rational('1')], False, True)
The explain_pickle function has several use cases.
Write pickling support for your classes
You can use explain_pickle to see what will happen when a pickle is unpickled. Consider: is this sequence of commands something that can be easily supported in all future Sage versions, or does it expose internal design decisions that are subject to change?
Debug old pickles
If you have a pickle from an old version of Sage that no longer unpickles, you can use explain_pickle to see what it is trying to do, to figure out how to fix it.
Use explain_pickle in doctests to help maintenance
If you have a
loads(dumps(S))
doctest, you could also add anexplain_pickle(dumps(S))
doctest. Then if something changes in a way that would invalidate old pickles, the output ofexplain_pickle
will also change. At that point, you can add the previous output ofexplain_pickle
as a new set of doctests (and then update the :obj`explain_pickle` doctest to use the new output), to ensure that old pickles will continue to work. (These problems will also be caught using thepicklejar
, but having the tests directly in the relevant module is clearer.)
As mentioned above, there are several output modes for explain_pickle
,
that control fidelity versus simplicity of the output. For example,
the GLOBAL instruction takes a module name and a class name and
produces the corresponding class. So GLOBAL of sage.rings.integer
,
Integer
is approximately equivalent to sage.rings.integer.Integer
.
However, this class lookup process can be customized (using
sage.structure.sage_object.register_unpickle_override). For instance,
if some future version of Sage renamed sage/rings/integer.pyx
to
sage/rings/knuth_was_here.pyx
, old pickles would no longer work unless
register_unpickle_override was used; in that case, GLOBAL of
‘sage.rings.integer’, ‘integer’ would mean
sage.rings.knuth_was_here.integer
.
By default, explain_pickle
will map this GLOBAL instruction to
unpickle_global('sage.rings.integer', 'integer')
. Then when this code
is evaluated, unpickle_global will look up the current mapping in the
register_unpickle_override table, so the generated code will continue
to work even in hypothetical future versions of Sage where integer.pyx
has been renamed.
If you pass the flag in_current_sage=True
, then
explain_pickle
will generate code that may only work in the
current version of Sage, not in future versions. In this case, it
would generate:
from sage.rings.integer import integer
and if you ran explain_pickle in hypothetical future sage, it would generate:
from sage.rings.knuth_was_here import integer
but the current code wouldn’t work in the future sage.
If you pass the flag default_assumptions=True
, then
explain_pickle
will generate code that would work in the
absence of any special unpickling information. That is, in either
current Sage or hypothetical future Sage, it would generate:
from sage.rings.integer import integer
The intention is that default_assumptions
output is prettier (more
human-readable), but may not actually work; so it is only intended for
human reading.
There are several functions used in the output of explain_pickle
.
Here I give a brief description of what they usually do, as well as
how to modify their operation (for instance, if you’re trying to get
old pickles to work).
unpickle_global(module, classname)
: unpickle_global(‘sage.foo.bar’, ‘baz’) is usually equivalent to sage.foo.bar.baz, but this can be customized with register_unpickle_override.unpickle_newobj(klass, args)
: Usually equivalent toklass.__new__(klass, *args)
. Ifklass
is a Python class, then you can define__new__()
to control the result (this result actually need not be an instance of klass). (This doesn’t work for Cython classes.)unpickle_build(obj, state)
: Ifobj
has a__setstate__()
method, then this is equivalent toobj.__setstate__(state)
. Otherwise uses state to set the attributes ofobj
. Customize by defining__setstate__()
.unpickle_instantiate(klass, args)
: Usually equivalent toklass(*args)
. Cannot be customized.- unpickle_appends(lst, vals): Appends the values in vals to lst. If not
isinstance(lst, list)
, can be customized by defining aappend()
method.
-
class
sage.misc.explain_pickle.
EmptyNewstyleClass
¶ Bases:
object
A featureless new-style class (inherits from object); used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
EmptyOldstyleClass
¶ A featureless old-style class (does not inherit from object); used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
PickleDict
(items)¶ Bases:
object
An object which can be used as the value of a PickleObject. The items is a list of key-value pairs, where the keys and values are SageInputExpressions. We use this to help construct dictionary literals, instead of always starting with an empty dictionary and assigning to it.
-
class
sage.misc.explain_pickle.
PickleExplainer
(sib, in_current_sage=False, default_assumptions=False, pedantic=False)¶ Bases:
object
An interpreter for the pickle virtual machine, that executes symbolically and constructs SageInputExpressions instead of directly constructing values.
-
APPEND
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(['a']) 0: \x80 PROTO 2 2: ] EMPTY_LIST 3: q BINPUT 1 5: U SHORT_BINSTRING 'a' 8: a APPEND 9: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ['a'] result: ['a']
As shown above, we prefer to create a list literal. This is not possible if the list is recursive:
sage: v = [] sage: v.append(v) sage: test_pickle(v) 0: \x80 PROTO 2 2: ] EMPTY_LIST 3: q BINPUT 1 5: h BINGET 1 7: a APPEND 8: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = [] list.append(si, si) si result: [[...]]
-
APPENDS
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(['a', 'b']) 0: \x80 PROTO 2 2: ] EMPTY_LIST 3: q BINPUT 1 5: ( MARK 6: U SHORT_BINSTRING 'a' 9: U SHORT_BINSTRING 'b' 12: e APPENDS (MARK at 5) 13: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ['a', 'b'] result: ['a', 'b']
As shown above, we prefer to create a list literal. This is not possible if the list is recursive:
sage: v = [] sage: v.append(v) sage: v.append(v) sage: test_pickle(v) 0: \x80 PROTO 2 2: ] EMPTY_LIST 3: q BINPUT 1 5: ( MARK 6: h BINGET 1 8: h BINGET 1 10: e APPENDS (MARK at 5) 11: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = [] list.extend(si, [si, si]) si result: [[...], [...]]
-
BINFLOAT
(f)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(float(pi)) 0: \x80 PROTO 2 2: G BINFLOAT 3.141592653589793 11: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: float(RR(3.1415926535897931)) result: 3.141592653589793
-
BINGET
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + BINPUT + 'x' + POP + BINGET + 'x' + '.') 0: ] EMPTY_LIST 1: q BINPUT 120 3: 0 POP 4: h BINGET 120 6: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
-
BININT
(n)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(dumps(100000r, compress=False)) 0: \x80 PROTO 2 2: J BININT 100000 7: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 100000 result: 100000
-
BININT1
(n)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(dumps(100r, compress=False)) 0: \x80 PROTO 2 2: K BININT1 100 4: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 100 result: 100
-
BININT2
(n)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(dumps(1000r, compress=False)) 0: \x80 PROTO 2 2: M BININT2 1000 5: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 1000 result: 1000
-
BINPERSID
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(INT + "0\n" + BINPERSID + '.', args=('Yo!',)) 0: I INT 0 3: Q BINPERSID 4: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: unpickle_persistent(0) result: 'Yo!'
-
BINPUT
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + BINPUT + 'x' + POP + BINGET + 'x') 0: ] EMPTY_LIST 1: q BINPUT 120 3: 0 POP 4: h BINGET 120 6: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
-
BINSTRING
(s)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle('T\5\0\0\0hello.') 0: T BINSTRING 'hello' 10: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: 'hello' result: 'hello'
-
BINUNICODE
(s)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(u'hi\u1234\U00012345') 0: \x80 PROTO 2 2: X BINUNICODE u'hi\u1234\U00012345' 16: q BINPUT 1 18: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: u'hi\u1234\U00012345' result: u'hi\u1234\U00012345'
-
BUILD
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(TestBuild()) 0: \x80 PROTO 2 2: c GLOBAL 'sage.misc.explain_pickle TestBuild' 38: q BINPUT 1 40: ) EMPTY_TUPLE 41: \x81 NEWOBJ 42: q BINPUT 2 44: } EMPTY_DICT 45: q BINPUT 3 47: U SHORT_BINSTRING 'x' 50: K BININT1 3 52: s SETITEM 53: } EMPTY_DICT 54: q BINPUT 4 56: U SHORT_BINSTRING 'y' 59: K BININT1 4 61: s SETITEM 62: \x86 TUPLE2 63: b BUILD 64: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from sage.misc.explain_pickle import TestBuild si = unpickle_newobj(TestBuild, ()) si.__dict__['x'] = 3 si.y = 4 si explain_pickle in_current_sage=False: pg_TestBuild = unpickle_global('sage.misc.explain_pickle', 'TestBuild') si = unpickle_newobj(pg_TestBuild, ()) unpickle_build(si, ({'x':3}, {'y':4})) si result: TestBuild: x=3; y=4
sage: test_pickle(TestBuildSetstate(), verbose_eval=True) 0: \x80 PROTO 2 2: c GLOBAL 'sage.misc.explain_pickle TestBuildSetstate' 46: q BINPUT 1 48: ) EMPTY_TUPLE 49: \x81 NEWOBJ 50: q BINPUT 2 52: } EMPTY_DICT 53: q BINPUT 3 55: U SHORT_BINSTRING 'x' 58: K BININT1 3 60: s SETITEM 61: } EMPTY_DICT 62: q BINPUT 4 64: U SHORT_BINSTRING 'y' 67: K BININT1 4 69: s SETITEM 70: \x86 TUPLE2 71: b BUILD 72: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from sage.misc.explain_pickle import TestBuildSetstate si = unpickle_newobj(TestBuildSetstate, ()) si.__setstate__(({'x':3}, {'y':4})) si explain_pickle in_current_sage=False: pg_TestBuildSetstate = unpickle_global('sage.misc.explain_pickle', 'TestBuildSetstate') si = unpickle_newobj(pg_TestBuildSetstate, ()) unpickle_build(si, ({'x':3}, {'y':4})) si evaluating explain_pickle in_current_sage=True: setting state from ({'x': 3}, {'y': 4}) evaluating explain_pickle in_current_sage=False: setting state from ({'x': 3}, {'y': 4}) loading pickle with cPickle: setting state from ({'x': 3}, {'y': 4}) result: TestBuild: x=4; y=3
-
DICT
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(DICT, args=('mark', 'a', 1, 2, 'b')) 0: ( MARK 1: P PERSID '1' 4: P PERSID '2' 7: P PERSID '3' 10: P PERSID '4' 13: d DICT (MARK at 0) 14: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: {unpickle_persistent('1'):unpickle_persistent('2'), unpickle_persistent('3'):unpickle_persistent('4')} result: {'a': 1, 2: 'b'}
-
DUP
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + DUP + TUPLE2 + STOP) 0: ] EMPTY_LIST 1: 2 DUP 2: \x86 TUPLE2 3: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = [] (si, si) result: ([], [])
-
EMPTY_DICT
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_DICT) 0: } EMPTY_DICT 1: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: {} result: {}
-
EMPTY_LIST
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST) 0: ] EMPTY_LIST 1: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
-
EMPTY_TUPLE
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_TUPLE) 0: ) EMPTY_TUPLE 1: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: () result: ()
-
EXT1
(n)¶ TESTS:
sage: from six.moves.copyreg import * sage: from sage.misc.explain_pickle import * sage: add_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 42) sage: test_pickle(EmptyNewstyleClass()) 0: \x80 PROTO 2 2: \x82 EXT1 42 4: ) EMPTY_TUPLE 5: \x81 NEWOBJ 6: q BINPUT 1 8: } EMPTY_DICT 9: q BINPUT 2 11: b BUILD 12: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = unpickle_newobj(unpickle_extension(42), ()) unpickle_build(si, {}) si result: EmptyNewstyleClass sage: remove_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 42)
-
EXT2
(n)¶ TESTS:
sage: from six.moves.copyreg import * sage: from sage.misc.explain_pickle import * sage: add_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 31415) sage: test_pickle(EmptyNewstyleClass()) 0: \x80 PROTO 2 2: \x83 EXT2 31415 5: ) EMPTY_TUPLE 6: \x81 NEWOBJ 7: q BINPUT 1 9: } EMPTY_DICT 10: q BINPUT 2 12: b BUILD 13: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = unpickle_newobj(unpickle_extension(31415), ()) unpickle_build(si, {}) si result: EmptyNewstyleClass sage: remove_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 31415)
-
EXT4
(n)¶ TESTS:
sage: from six.moves.copyreg import * sage: from sage.misc.explain_pickle import * sage: add_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 27182818) sage: test_pickle(EmptyNewstyleClass()) 0: \x80 PROTO 2 2: \x84 EXT4 27182818 7: ) EMPTY_TUPLE 8: \x81 NEWOBJ 9: q BINPUT 1 11: } EMPTY_DICT 12: q BINPUT 2 14: b BUILD 15: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si = unpickle_newobj(unpickle_extension(27182818), ()) unpickle_build(si, {}) si result: EmptyNewstyleClass sage: remove_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 27182818)
-
FLOAT
(f)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(FLOAT + '2.71828\n') 0: F FLOAT 2.71828 9: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: 2.71828 result: 2.71828
-
GET
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + PUT + '1\n' + POP + GET + '1\n' + '.') 0: ] EMPTY_LIST 1: p PUT 1 4: 0 POP 5: g GET 1 8: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
-
GLOBAL
(name)¶ TESTS:
sage: from sage.misc.explain_pickle import *
We’ve used register_unpickle_override so that unpickle_global will map TestGlobalOldName to TestGlobalNewName.
sage: test_pickle(TestGlobalOldName()) 0: \x80 PROTO 2 2: c GLOBAL 'sage.misc.explain_pickle TestGlobalOldName' 46: q BINPUT 1 48: ) EMPTY_TUPLE 49: \x81 NEWOBJ 50: q BINPUT 2 52: } EMPTY_DICT 53: q BINPUT 3 55: b BUILD 56: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from sage.misc.explain_pickle import TestGlobalNewName unpickle_newobj(TestGlobalNewName, ()) explain_pickle in_current_sage=False: pg_TestGlobalOldName = unpickle_global('sage.misc.explain_pickle', 'TestGlobalOldName') si = unpickle_newobj(pg_TestGlobalOldName, ()) unpickle_build(si, {}) si result: TestGlobalNewName
Note that default_assumptions blithely assumes that it should use the old name, giving code that doesn’t actually work as desired:
sage: explain_pickle(dumps(TestGlobalOldName()), default_assumptions=True) from sage.misc.explain_pickle import TestGlobalOldName unpickle_newobj(TestGlobalOldName, ())
A class name need not be a valid identifier:
sage: sage.misc.explain_pickle.__dict__['funny$name'] = TestGlobalFunnyName # see comment at end of file sage: test_pickle((TestGlobalFunnyName(), TestGlobalFunnyName())) 0: \x80 PROTO 2 2: c GLOBAL 'sage.misc.explain_pickle funny$name' 39: q BINPUT 1 41: ) EMPTY_TUPLE 42: \x81 NEWOBJ 43: q BINPUT 2 45: } EMPTY_DICT 46: q BINPUT 3 48: b BUILD 49: h BINGET 1 51: ) EMPTY_TUPLE 52: \x81 NEWOBJ 53: q BINPUT 4 55: } EMPTY_DICT 56: q BINPUT 5 58: b BUILD 59: \x86 TUPLE2 60: q BINPUT 6 62: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: si1 = unpickle_global('sage.misc.explain_pickle', 'funny$name') si2 = unpickle_newobj(si1, ()) unpickle_build(si2, {}) si3 = unpickle_newobj(si1, ()) unpickle_build(si3, {}) (si2, si3) result: (TestGlobalFunnyName, TestGlobalFunnyName)
-
INST
(name)¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps(EmptyOldstyleClass(), protocol=0)) 0: ( MARK 1: i INST 'sage.misc.explain_pickle EmptyOldstyleClass' (MARK at 0) 46: p PUT 0 49: ( MARK 50: d DICT (MARK at 49) 51: p PUT 1 54: b BUILD 55: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True: from types import InstanceType from sage.misc.explain_pickle import EmptyOldstyleClass InstanceType(EmptyOldstyleClass) explain_pickle in_current_sage=False: pg_EmptyOldstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyOldstyleClass') pg = unpickle_instantiate(pg_EmptyOldstyleClass, ()) unpickle_build(pg, {}) pg result: EmptyOldstyleClass
-
INT
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(INT + "-12345\n") 0: I INT -12345 8: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: -12345 result: -12345
INT can also be used to record True and False:
sage: test_pickle(INT + "00\n") 0: I INT False 4: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: False result: False sage: test_pickle(INT + "01\n") 0: I INT True 4: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: True result: True
-
LIST
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(MARK + NONE + NEWFALSE + LIST) 0: ( MARK 1: N NONE 2: \x89 NEWFALSE 3: l LIST (MARK at 0) 4: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: [None, False] result: [None, False]
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LONG
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(LONG + "12345678909876543210123456789L\n") 0: L LONG 12345678909876543210123456789L 32: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: 12345678909876543210123456789 result: 12345678909876543210123456789L
-
LONG1
(n)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(1L) 0: \x80 PROTO 2 2: \x8a LONG1 1L 5: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 1L result: 1L
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LONG4
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(LONG4 + '\014\0\0\0' + 'hello, world') 0: \x8b LONG4 31079605376604435891501163880L 17: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 31079605376604435891501163880 result: 31079605376604435891501163880L
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LONG_BINGET
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + LONG_BINPUT + 'Sage' + POP + LONG_BINGET + 'Sage') 0: ] EMPTY_LIST 1: r LONG_BINPUT 1701273939 6: 0 POP 7: j LONG_BINGET 1701273939 12: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
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LONG_BINPUT
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + LONG_BINPUT + 'Sage' + POP + LONG_BINGET + 'Sage') 0: ] EMPTY_LIST 1: r LONG_BINPUT 1701273939 6: 0 POP 7: j LONG_BINGET 1701273939 12: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
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MARK
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(MARK + TUPLE) 0: ( MARK 1: t TUPLE (MARK at 0) 2: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: () result: ()
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NEWFALSE
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(NEWFALSE) 0: \x89 NEWFALSE 1: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: False result: False
-
NEWOBJ
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(EmptyNewstyleClass()) 0: \x80 PROTO 2 2: c GLOBAL 'sage.misc.explain_pickle EmptyNewstyleClass' 47: q BINPUT 1 49: ) EMPTY_TUPLE 50: \x81 NEWOBJ 51: q BINPUT 2 53: } EMPTY_DICT 54: q BINPUT 3 56: b BUILD 57: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from sage.misc.explain_pickle import EmptyNewstyleClass unpickle_newobj(EmptyNewstyleClass, ()) explain_pickle in_current_sage=False: pg_EmptyNewstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyNewstyleClass') si = unpickle_newobj(pg_EmptyNewstyleClass, ()) unpickle_build(si, {}) si result: EmptyNewstyleClass
-
NEWTRUE
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(NEWTRUE) 0: \x88 NEWTRUE 1: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: True result: True
-
NONE
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(NONE) 0: N NONE 1: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: None result: None
-
OBJ
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(EmptyOldstyleClass()) 0: \x80 PROTO 2 2: ( MARK 3: c GLOBAL 'sage.misc.explain_pickle EmptyOldstyleClass' 48: q BINPUT 1 50: o OBJ (MARK at 2) 51: q BINPUT 2 53: } EMPTY_DICT 54: q BINPUT 3 56: b BUILD 57: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from types import InstanceType from sage.misc.explain_pickle import EmptyOldstyleClass InstanceType(EmptyOldstyleClass) explain_pickle in_current_sage=False: pg_EmptyOldstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyOldstyleClass') pg = unpickle_instantiate(pg_EmptyOldstyleClass, ()) unpickle_build(pg, {}) pg result: EmptyOldstyleClass
-
PERSID
(id)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(PERSID + "0\n" + '.', args=('Yo!',)) 0: P PERSID '0' 3: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: unpickle_persistent('0') result: 'Yo!'
-
POP
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(INT + "0\n" + POP + INT + "42\n") 0: I INT 0 3: 0 POP 4: I INT 42 8: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: 42 result: 42
-
POP_MARK
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(MARK + NONE + NEWFALSE + POP_MARK + NEWTRUE) 0: ( MARK 1: N NONE 2: \x89 NEWFALSE 3: 1 POP_MARK (MARK at 0) 4: \x88 NEWTRUE 5: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: True result: True
-
PROTO
(proto)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(0r) 0: \x80 PROTO 2 2: K BININT1 0 4: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 0 result: 0
-
PUT
(n)¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_LIST + PUT + '1\n' + POP + GET + '1\n' + '.') 0: ] EMPTY_LIST 1: p PUT 1 4: 0 POP 5: g GET 1 8: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: [] result: []
-
REDUCE
()¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps(EmptyNewstyleClass(), protocol=1)) 0: c GLOBAL 'copy_reg _reconstructor' 25: q BINPUT 0 27: ( MARK 28: c GLOBAL 'sage.misc.explain_pickle EmptyNewstyleClass' 73: q BINPUT 1 75: c GLOBAL '__builtin__ object' 95: q BINPUT 2 97: N NONE 98: t TUPLE (MARK at 27) 99: q BINPUT 3 101: R REDUCE 102: q BINPUT 4 104: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True: from copy_reg import _reconstructor from sage.misc.explain_pickle import EmptyNewstyleClass from __builtin__ import object _reconstructor(EmptyNewstyleClass, object, None) explain_pickle in_current_sage=False: pg__reconstructor = unpickle_global('copy_reg', '_reconstructor') pg_EmptyNewstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyNewstyleClass') pg_object = unpickle_global('__builtin__', 'object') pg__reconstructor(pg_EmptyNewstyleClass, pg_object, None) result: EmptyNewstyleClass
sage: test_pickle(TestReduceGetinitargs(), verbose_eval=True) Running __init__ for TestReduceGetinitargs 0: \x80 PROTO 2 2: ( MARK 3: c GLOBAL 'sage.misc.explain_pickle TestReduceGetinitargs' 51: q BINPUT 1 53: o OBJ (MARK at 2) 54: q BINPUT 2 56: } EMPTY_DICT 57: q BINPUT 3 59: b BUILD 60: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from sage.misc.explain_pickle import TestReduceGetinitargs TestReduceGetinitargs() explain_pickle in_current_sage=False: pg_TestReduceGetinitargs = unpickle_global('sage.misc.explain_pickle', 'TestReduceGetinitargs') pg = unpickle_instantiate(pg_TestReduceGetinitargs, ()) unpickle_build(pg, {}) pg evaluating explain_pickle in_current_sage=True: Running __init__ for TestReduceGetinitargs evaluating explain_pickle in_current_sage=False: Running __init__ for TestReduceGetinitargs loading pickle with cPickle: Running __init__ for TestReduceGetinitargs result: TestReduceGetinitargs
sage: test_pickle(TestReduceNoGetinitargs(), verbose_eval=True) Running __init__ for TestReduceNoGetinitargs 0: \x80 PROTO 2 2: ( MARK 3: c GLOBAL 'sage.misc.explain_pickle TestReduceNoGetinitargs' 53: q BINPUT 1 55: o OBJ (MARK at 2) 56: q BINPUT 2 58: } EMPTY_DICT 59: q BINPUT 3 61: b BUILD 62: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: from types import InstanceType from sage.misc.explain_pickle import TestReduceNoGetinitargs InstanceType(TestReduceNoGetinitargs) explain_pickle in_current_sage=False: pg_TestReduceNoGetinitargs = unpickle_global('sage.misc.explain_pickle', 'TestReduceNoGetinitargs') pg = unpickle_instantiate(pg_TestReduceNoGetinitargs, ()) unpickle_build(pg, {}) pg evaluating explain_pickle in_current_sage=True: evaluating explain_pickle in_current_sage=False: loading pickle with cPickle: result: TestReduceNoGetinitargs
-
SETITEM
()¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps({'a': 'b'})) 0: ( MARK 1: d DICT (MARK at 0) 2: p PUT 0 5: S STRING 'a' 10: p PUT 1 13: S STRING 'b' 18: p PUT 2 21: s SETITEM 22: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: {'a':'b'} result: {'a': 'b'}
We see above that we output the result as a dictionary literal, when possible. This is impossible when a key or value is recursive. First we test recursive values:
sage: value_rec = dict() sage: value_rec['circular'] = value_rec sage: test_pickle(pickle.dumps(value_rec)) 0: ( MARK 1: d DICT (MARK at 0) 2: p PUT 0 5: S STRING 'circular' 17: p PUT 1 20: g GET 0 23: s SETITEM 24: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: si = {} si['circular'] = si si result: {'circular': {...}}
Then we test recursive keys:
sage: key_rec = dict() sage: key = EmptyNewstyleClass() sage: key.circular = key_rec sage: key_rec[key] = 'circular' sage: test_pickle(pickle.dumps(key_rec)) 0: ( MARK 1: d DICT (MARK at 0) 2: p PUT 0 5: c GLOBAL 'copy_reg _reconstructor' 30: p PUT 1 33: ( MARK 34: c GLOBAL 'sage.misc.explain_pickle EmptyNewstyleClass' 79: p PUT 2 82: c GLOBAL '__builtin__ object' 102: p PUT 3 105: N NONE 106: t TUPLE (MARK at 33) 107: p PUT 4 110: R REDUCE 111: p PUT 5 114: ( MARK 115: d DICT (MARK at 114) 116: p PUT 6 119: S STRING 'circular' 131: p PUT 7 134: g GET 0 137: s SETITEM 138: b BUILD 139: g GET 7 142: s SETITEM 143: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True: si1 = {} from copy_reg import _reconstructor from sage.misc.explain_pickle import EmptyNewstyleClass from __builtin__ import object si2 = _reconstructor(EmptyNewstyleClass, object, None) si2.__dict__['circular'] = si1 si1[si2] = 'circular' si1 explain_pickle in_current_sage=False: si1 = {} pg__reconstructor = unpickle_global('copy_reg', '_reconstructor') pg_EmptyNewstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyNewstyleClass') pg_object = unpickle_global('__builtin__', 'object') si2 = pg__reconstructor(pg_EmptyNewstyleClass, pg_object, None) unpickle_build(si2, {'circular':si1}) si1[si2] = 'circular' si1 result: {EmptyNewstyleClass: 'circular'}
-
SETITEMS
()¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps({'a': 'b', 1r : 2r}, protocol=2)) 0: \x80 PROTO 2 2: } EMPTY_DICT 3: q BINPUT 0 5: ( MARK 6: U SHORT_BINSTRING 'a' 9: q BINPUT 1 11: U SHORT_BINSTRING 'b' 14: q BINPUT 2 16: K BININT1 1 18: K BININT1 2 20: u SETITEMS (MARK at 5) 21: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: {'a':'b', 1:2} result: {'a': 'b', 1: 2}
Similar to the tests for SETITEM, we test recursive keys and values:
sage: recdict = {} sage: recdict['Circular value'] = recdict sage: key = EmptyOldstyleClass() sage: key.recdict = recdict sage: recdict[key] = 'circular_key' sage: test_pickle(pickle.dumps(recdict, protocol=2)) 0: \x80 PROTO 2 2: } EMPTY_DICT 3: q BINPUT 0 5: ( MARK 6: ( MARK 7: c GLOBAL 'sage.misc.explain_pickle EmptyOldstyleClass' 52: q BINPUT 1 54: o OBJ (MARK at 6) 55: q BINPUT 2 57: } EMPTY_DICT 58: q BINPUT 3 60: U SHORT_BINSTRING 'recdict' 69: q BINPUT 4 71: h BINGET 0 73: s SETITEM 74: b BUILD 75: U SHORT_BINSTRING 'circular_key' 89: q BINPUT 5 91: U SHORT_BINSTRING 'Circular value' 107: q BINPUT 6 109: h BINGET 0 111: u SETITEMS (MARK at 5) 112: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True: si1 = {} from types import InstanceType from sage.misc.explain_pickle import EmptyOldstyleClass si2 = InstanceType(EmptyOldstyleClass) si2.__dict__['recdict'] = si1 si1[si2] = 'circular_key' si1['Circular value'] = si1 si1 explain_pickle in_current_sage=False: si = {} pg_EmptyOldstyleClass = unpickle_global('sage.misc.explain_pickle', 'EmptyOldstyleClass') pg = unpickle_instantiate(pg_EmptyOldstyleClass, ()) unpickle_build(pg, {'recdict':si}) si[pg] = 'circular_key' si['Circular value'] = si si result: {EmptyOldstyleClass: 'circular_key', 'Circular value': {...}}
-
SHORT_BINSTRING
(s)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(dumps('hello', compress=False)) 0: \x80 PROTO 2 2: U SHORT_BINSTRING 'hello' 9: q BINPUT 1 11: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: 'hello' result: 'hello'
-
STOP
()¶ TESTS:
sage: from pickle import * sage: from sage.misc.explain_pickle import * sage: test_pickle(EMPTY_TUPLE) 0: ) EMPTY_TUPLE 1: . STOP highest protocol among opcodes = 1 explain_pickle in_current_sage=True/False: () result: ()
-
STRING
(s)¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle("S'Testing...'\n.") 0: S STRING 'Testing...' 14: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: 'Testing...' result: 'Testing...'
-
TUPLE
()¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps(('a',))) 0: ( MARK 1: S STRING 'a' 6: p PUT 0 9: t TUPLE (MARK at 0) 10: p PUT 1 13: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: ('a',) result: ('a',)
We prefer to produce tuple literals, as above; but if the tuple is recursive, we need a more complicated construction. It used to be the case that the cPickle unpickler couldn’t handle this case, but that’s no longer true (see http://bugs.python.org/issue5794):
sage: v = ([],) sage: v[0].append(v) sage: test_pickle(pickle.dumps(v)) 0: ( MARK 1: ( MARK 2: l LIST (MARK at 1) 3: p PUT 0 6: ( MARK 7: g GET 0 10: t TUPLE (MARK at 6) 11: p PUT 1 14: a APPEND 15: 0 POP 16: 0 POP (MARK at 0) 17: g GET 1 20: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: si1 = [] si2 = (si1,) list.append(si1, si2) si2 result: ([(...)],)
-
TUPLE1
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(('a',)) 0: \x80 PROTO 2 2: U SHORT_BINSTRING 'a' 5: \x85 TUPLE1 6: q BINPUT 1 8: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ('a',) result: ('a',)
-
TUPLE2
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(('a','b')) 0: \x80 PROTO 2 2: U SHORT_BINSTRING 'a' 5: U SHORT_BINSTRING 'b' 8: \x86 TUPLE2 9: q BINPUT 1 11: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ('a', 'b') result: ('a', 'b')
-
TUPLE3
()¶ TESTS:
sage: from sage.misc.explain_pickle import * sage: test_pickle(('a','b','c')) 0: \x80 PROTO 2 2: U SHORT_BINSTRING 'a' 5: U SHORT_BINSTRING 'b' 8: U SHORT_BINSTRING 'c' 11: \x87 TUPLE3 12: q BINPUT 1 14: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ('a', 'b', 'c') result: ('a', 'b', 'c')
-
UNICODE
(s)¶ TESTS:
sage: import pickle sage: from sage.misc.explain_pickle import * sage: test_pickle(pickle.dumps(u'hi\u1234\U00012345')) 0: V UNICODE u'hi\u1234\U00012345' 20: p PUT 0 23: . STOP highest protocol among opcodes = 0 explain_pickle in_current_sage=True/False: u'hi\u1234\U00012345' result: u'hi\u1234\U00012345'
-
check_value
(v)¶ Check that the given value is either a SageInputExpression or a PickleObject. Used for internal sanity checking.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.check_value(7) Traceback (most recent call last): ... AssertionError sage: pe.check_value(sib(7))
-
is_mutable_pickle_object
(v)¶ Test whether a PickleObject is mutable (has never been converted to a SageInputExpression).
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: v = PickleObject(1, sib(1)) sage: pe.is_mutable_pickle_object(v) True sage: sib(v) {atomic:1} sage: pe.is_mutable_pickle_object(v) False
-
pop
()¶ Pop a value from the virtual machine’s stack, and return it.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.push(sib(7)) sage: pe.pop() {atomic:7}
-
pop_to_mark
()¶ Pop all values down to the ‘mark’ from the virtual machine’s stack, and return the values as a list.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.push_mark() sage: pe.push(sib(7)) sage: pe.push(sib('hello')) sage: pe.pop_to_mark() [{atomic:7}, {atomic:'hello'}]
-
push
(v)¶ Push a value onto the virtual machine’s stack.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.push(sib(7)) sage: pe.stack[-1] {atomic:7}
Push a value onto the virtual machine’s stack; also mark it as shared for sage_input if we are in pedantic mode.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.push_and_share(sib(7)) sage: pe.stack[-1] {atomic:7} sage: pe.stack[-1]._sie_share True
-
push_mark
()¶ Push a ‘mark’ onto the virtual machine’s stack.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: pe.push_mark() sage: pe.stack[-1] 'mark' sage: pe.stack[-1] is the_mark True
-
run_pickle
(p)¶ Given an (uncompressed) pickle as a string, run the pickle in this virtual machine. Once a STOP has been executed, return the result (a SageInputExpression representing code which, when evaluated, will give the value of the pickle).
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: sib(pe.run_pickle('T\5\0\0\0hello.')) {atomic:'hello'}
Mark a sage_input value as shared, if we are in pedantic mode.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: from sage.misc.sage_input import SageInputBuilder sage: sib = SageInputBuilder() sage: pe = PickleExplainer(sib, in_current_sage=True, default_assumptions=False, pedantic=True) sage: v = sib(7) sage: v._sie_share False sage: pe.share(v) {atomic:7} sage: v._sie_share True
-
-
class
sage.misc.explain_pickle.
PickleInstance
(klass)¶ Bases:
object
An object which can be used as the value of a PickleObject. Unlike other possible values of a PickleObject, a PickleInstance doesn’t represent an exact value; instead, it gives the class (type) of the object.
-
class
sage.misc.explain_pickle.
PickleObject
(value, expression)¶ Bases:
object
Pickles have a stack-based virtual machine. The explain_pickle pickle interpreter mostly uses SageInputExpressions, from sage_input, as the stack values. However, sometimes we want some more information about the value on the stack, so that we can generate better (prettier, less confusing) code. In such cases, we push a PickleObject instead of a SageInputExpression. A PickleObject contains a value (which may be a standard Python value, or a PickleDict or PickleInstance), an expression (a SageInputExpression), and an “immutable” flag (which checks whether this object has been converted to a SageInputExpression; if it has, then we must not mutate the object, since the SageInputExpression would not reflect the changes).
-
class
sage.misc.explain_pickle.
TestAppendList
¶ Bases:
list
A subclass of list, with deliberately-broken append and extend methods. Used for testing explain_pickle.
-
append
()¶ A deliberately broken append method.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: v = TestAppendList() sage: v.append(7) Traceback (most recent call last): ... TypeError: append() takes exactly 1 argument (2 given)
- We can still append by directly using the list method:
- sage: list.append(v, 7) sage: v [7]
-
extend
()¶ A deliberately broken extend method.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: v = TestAppendList() sage: v.extend([3,1,4,1,5,9]) Traceback (most recent call last): ... TypeError: extend() takes exactly 1 argument (2 given)
- We can still extend by directly using the list method:
- sage: list.extend(v, (3,1,4,1,5,9)) sage: v [3, 1, 4, 1, 5, 9]
-
-
class
sage.misc.explain_pickle.
TestAppendNonlist
¶ Bases:
object
A list-like class, carefully designed to test exact unpickling behavior. Used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
TestBuild
¶ Bases:
object
A simple class with a __getstate__ but no __setstate__. Used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
TestBuildSetstate
¶ Bases:
sage.misc.explain_pickle.TestBuild
A simple class with a __getstate__ and a __setstate__. Used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
TestGlobalFunnyName
¶ Bases:
object
A featureless new-style class which has a name that’s not a legal Python identifier.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: globals()['funny$name'] = TestGlobalFunnyName # see comment at end of file sage: TestGlobalFunnyName.__name__ 'funny$name' sage: globals()['funny$name'] is TestGlobalFunnyName True
-
class
sage.misc.explain_pickle.
TestGlobalNewName
¶ Bases:
object
A featureless new-style class. When you try to unpickle an instance of TestGlobalOldName, it is redirected to create an instance of this class instead. Used for testing explain_pickle.
- EXAMPLES:
- sage: from sage.misc.explain_pickle import * sage: loads(dumps(TestGlobalOldName())) TestGlobalNewName
-
class
sage.misc.explain_pickle.
TestGlobalOldName
¶ Bases:
object
A featureless new-style class. When you try to unpickle an instance of this class, it is redirected to create a TestGlobalNewName instead. Used for testing explain_pickle.
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: loads(dumps(TestGlobalOldName())) TestGlobalNewName
-
class
sage.misc.explain_pickle.
TestReduceGetinitargs
¶ An old-style class with a __getinitargs__ method. Used for testing explain_pickle.
-
class
sage.misc.explain_pickle.
TestReduceNoGetinitargs
¶ An old-style class with no __getinitargs__ method. Used for testing explain_pickle.
-
sage.misc.explain_pickle.
explain_pickle
(pickle=None, file=None, compress=True, **kwargs)¶ Explain a pickle. That is, produce source code such that evaluating the code is equivalent to loading the pickle. Feeding the result of
explain_pickle
tosage_eval
should be totally equivalent to loading thepickle
withcPickle
.INPUT:
pickle
– the pickle to explain, as a string (default: None)file
– a filename of a pickle (default: None)compress
– if False, don’t attempt to decompress the pickle- (default: True)
in_current_sage
– if True, produce potentially simpler code that is- tied to the current version of Sage. (default: False)
default_assumptions
– if True, produce potentially simpler code that- assumes that generic unpickling code will be used. This code may not actually work. (default: False)
eval
– if True, then evaluate the resulting code and return the- evaluated result. (default: False)
preparse
– if True, then produce code to be evaluated with- Sage’s preparser; if False, then produce standard Python code; if None, then produce code that will work either with or without the preparser. (default: True)
pedantic
– if True, then carefully ensures that the result has- at least as much sharing as the result of cPickle (it may have more, for immutable objects). (default: False)
Exactly one of
pickle
(a string containing a pickle) orfile
(the filename of a pickle) must be provided.EXAMPLES:
sage: explain_pickle(dumps({('a', 'b'): [1r, 2r]})) {('a', 'b'):[1r, 2r]} sage: explain_pickle(dumps(RR(pi)), in_current_sage=True) from sage.rings.real_mpfr import __create__RealNumber_version0 from sage.rings.real_mpfr import __create__RealField_version0 __create__RealNumber_version0(__create__RealField_version0(53r, False, 'RNDN'), '3.4gvml245kc0@0', 32r) sage: s = 'hi' sage: explain_pickle(dumps((s, s))) ('hi', 'hi') sage: explain_pickle(dumps((s, s)), pedantic=True) si = 'hi' (si, si) sage: explain_pickle(dumps(5r)) 5r sage: explain_pickle(dumps(5r), preparse=False) 5 sage: explain_pickle(dumps(5r), preparse=None) int(5) sage: explain_pickle(dumps(22/7)) pg_make_rational = unpickle_global('sage.rings.rational', 'make_rational') pg_make_rational('m/7') sage: explain_pickle(dumps(22/7), in_current_sage=True) from sage.rings.rational import make_rational make_rational('m/7') sage: explain_pickle(dumps(22/7), default_assumptions=True) from sage.rings.rational import make_rational make_rational('m/7')
-
sage.misc.explain_pickle.
explain_pickle_string
(pickle, in_current_sage=False, default_assumptions=False, eval=False, preparse=True, pedantic=False)¶ This is a helper function for explain_pickle. It takes a decompressed pickle string as input; other than that, its options are all the same as explain_pickle.
EXAMPLES:
sage: sage.misc.explain_pickle.explain_pickle_string(dumps("Hello, world", compress=False)) 'Hello, world'
(See the documentation for
explain_pickle
for many more examples.)
-
sage.misc.explain_pickle.
name_is_valid
(name)¶ Test whether a string is a valid Python identifier. (We use a conservative test, that only allows ASCII identifiers.)
EXAMPLES:
sage: from sage.misc.explain_pickle import name_is_valid sage: name_is_valid('fred') True sage: name_is_valid('Yes!ValidName') False sage: name_is_valid('_happy_1234') True
-
sage.misc.explain_pickle.
test_pickle
(p, verbose_eval=False, pedantic=False, args=())¶ Tests explain_pickle on a given pickle p. p can be:
- a string containing an uncompressed pickle (which will always end with a ‘.’)
- a string containing a pickle fragment (not ending with ‘.’) test_pickle will synthesize a pickle that will push args onto the stack (using persistent IDs), run the pickle fragment, and then STOP (if the string ‘mark’ occurs in args, then a mark will be pushed)
- an arbitrary object; test_pickle will pickle the object
Once it has a pickle, test_pickle will print the pickle’s disassembly, run explain_pickle with in_current_sage=True and False, print the results, evaluate the results, unpickle the object with cPickle, and compare all three results.
If verbose_eval is True, then test_pickle will print messages before evaluating the pickles; this is to allow for tests where the unpickling prints messages (to verify that the same operations occur in all cases).
EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: test_pickle(['a']) 0: \x80 PROTO 2 2: ] EMPTY_LIST 3: q BINPUT 1 5: U SHORT_BINSTRING 'a' 8: a APPEND 9: . STOP highest protocol among opcodes = 2 explain_pickle in_current_sage=True/False: ['a'] result: ['a']
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sage.misc.explain_pickle.
unpickle_appends
(lst, vals)¶ Given a list (or list-like object) and a sequence of values, appends the values to the end of the list. This is careful to do so using the exact same technique that cPickle would use. Used by
explain_pickle
.EXAMPLES:
sage: v = [] sage: unpickle_appends(v, (1, 2, 3)) sage: v [1, 2, 3]
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sage.misc.explain_pickle.
unpickle_build
(obj, state)¶ Set the state of an object. Used by
explain_pickle
.EXAMPLES:
sage: from sage.misc.explain_pickle import * sage: v = EmptyNewstyleClass() sage: unpickle_build(v, {'hello': 42}) sage: v.hello 42
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sage.misc.explain_pickle.
unpickle_extension
(code)¶ Takes an integer index and returns the extension object with that index. Used by
explain_pickle
.EXAMPLES:
sage: from six.moves.copyreg import * sage: add_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 42) sage: unpickle_extension(42) <class 'sage.misc.explain_pickle.EmptyNewstyleClass'> sage: remove_extension('sage.misc.explain_pickle', 'EmptyNewstyleClass', 42)
-
sage.misc.explain_pickle.
unpickle_instantiate
(fn, args)¶ Instantiate a new object of class fn with arguments args. Almost always equivalent to
fn(*args)
. Used byexplain_pickle
.EXAMPLES:
sage: unpickle_instantiate(Integer, ('42',)) 42
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sage.misc.explain_pickle.
unpickle_newobj
(klass, args)¶ Create a new object; this corresponds to the C code klass->tp_new(klass, args, NULL). Used by
explain_pickle
.- EXAMPLES:
- sage: unpickle_newobj(tuple, ([1, 2, 3],)) (1, 2, 3)
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sage.misc.explain_pickle.
unpickle_persistent
(s)¶ Takes an integer index and returns the persistent object with that index; works by calling whatever callable is stored in unpickle_persistent_loader. Used by
explain_pickle
.EXAMPLES:
sage: import sage.misc.explain_pickle sage: sage.misc.explain_pickle.unpickle_persistent_loader = lambda n: n+7 sage: unpickle_persistent(35) 42