ImportError: Unknown magic number 3495 in test.pyc
在进行pyc文件反编译时遇到如下报错：
这个问题是我们生成的pyc文件本身存在的问题
pyc文件生成时，头部的magic number被清理，需要我们另外补上。
我们先观察对比一下正确的pyc文件头与报错的pyc文件头：
正常的pyc文件
丢头部的magic number的pyc文件
可以看到，头部确实是不一样的
33 0D 0D 0A 0E 58 1D 65 C2 01 00 00尝试直接将正常的pyc文件头复制给丢头部的magic number的pyc文件：
还是报错，查看生成的py文件也是空
在Python3.7及以上版本的编译后二进制文件中，头部除了四字节Magic Number，还有四个字节的空位和八个字节的时间戳+大小信息，后者对文件反编译没有影响，全部填充0即可；
Python3.3 - Python3.7（包含3.3）版本中，只需要Magic Number和八位时间戳+大小信息
Python3.3 以下的版本中，只有Magic Number和四位时间戳。
但是我没找到这个（我的是Python3.11 ╮(╯▽╰)╭ ）
只能给大家附上一些早期版本的Magic Number的对照表：
Known values:
# Python 1.5: 20121
# Python 1.5.1: 20121
# Python 1.5.2: 20121
# Python 1.6: 50428
# Python 2.0: 50823
# Python 2.0.1: 50823
# Python 2.1: 60202
# Python 2.1.1: 60202
# Python 2.1.2: 60202
# Python 2.2: 60717
# Python 2.3a0: 62011
# Python 2.3a0: 62021
# Python 2.3a0: 62011 (!)
# Python 2.4a0: 62041
# Python 2.4a3: 62051
# Python 2.4b1: 62061
# Python 2.5a0: 62071
# Python 2.5a0: 62081 (ast-branch)
# Python 2.5a0: 62091 (with)
# Python 2.5a0: 62092 (changed WITH_CLEANUP opcode)
# Python 2.5b3: 62101 (fix wrong code: for x, in ...)
# Python 2.5b3: 62111 (fix wrong code: x += yield)
# Python 2.5c1: 62121 (fix wrong lnotab with for loops and
# storing constants that should have been removed)
# Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)
# Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
# Python 2.6a1: 62161 (WITH_CLEANUP optimization)
# Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND)
# Python 2.7a0: 62181 (optimize conditional branches:
# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
# Python 2.7a0 62191 (introduce SETUP_WITH)
# Python 2.7a0 62201 (introduce BUILD_SET)
# Python 2.7a0 62211 (introduce MAP_ADD and SET_ADD)
# Python 3000: 3000
# 3010 (removed UNARY_CONVERT)
# 3020 (added BUILD_SET)
# 3030 (added keyword-only parameters)
# 3040 (added signature annotations)
# 3050 (print becomes a function)
# 3060 (PEP 3115 metaclass syntax)
# 3061 (string literals become unicode)
# 3071 (PEP 3109 raise changes)
# 3081 (PEP 3137 make __file__ and __name__ unicode)
# 3091 (kill str8 interning)
# 3101 (merge from 2.6a0, see 62151)
# 3103 (__file__ points to source file)
# Python 3.0a4: 3111 (WITH_CLEANUP optimization).
# Python 3.0b1: 3131 (lexical exception stacking, including POP_EXCEPT
#3021)
# Python 3.1a1: 3141 (optimize list, set and dict comprehensions:
# change LIST_APPEND and SET_ADD, add MAP_ADD #2183)
# Python 3.1a1: 3151 (optimize conditional branches:
# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE
#4715)
# Python 3.2a1: 3160 (add SETUP_WITH #6101)
# tag: cpython-32
# Python 3.2a2: 3170 (add DUP_TOP_TWO, remove DUP_TOPX and ROT_FOUR #9225)
# tag: cpython-32
# Python 3.2a3 3180 (add DELETE_DEREF #4617)
# Python 3.3a1 3190 (__class__ super closure changed)
# Python 3.3a1 3200 (PEP 3155 __qualname__ added #13448)
# Python 3.3a1 3210 (added size modulo 2**32 to the pyc header #13645)
# Python 3.3a2 3220 (changed PEP 380 implementation #14230)
# Python 3.3a4 3230 (revert changes to implicit __class__ closure #14857)
# Python 3.4a1 3250 (evaluate positional default arguments before
# keyword-only defaults #16967)
# Python 3.4a1 3260 (add LOAD_CLASSDEREF; allow locals of class to override
# free vars #17853)
# Python 3.4a1 3270 (various tweaks to the __class__ closure #12370)
# Python 3.4a1 3280 (remove implicit class argument)
# Python 3.4a4 3290 (changes to __qualname__ computation #19301)
# Python 3.4a4 3300 (more changes to __qualname__ computation #19301)
# Python 3.4rc2 3310 (alter __qualname__ computation #20625)
# Python 3.5a1 3320 (PEP 465: Matrix multiplication operator #21176)
# Python 3.5b1 3330 (PEP 448: Additional Unpacking Generalizations #2292)
# Python 3.5b2 3340 (fix dictionary display evaluation order #11205)
# Python 3.5b3 3350 (add GET_YIELD_FROM_ITER opcode #24400)
# Python 3.5.2 3351 (fix BUILD_MAP_UNPACK_WITH_CALL opcode #27286)
# Python 3.6a0 3360 (add FORMAT_VALUE opcode #25483)
# Python 3.6a1 3361 (lineno delta of code.co_lnotab becomes signed #26107)
# Python 3.6a2 3370 (16 bit wordcode #26647)
# Python 3.6a2 3371 (add BUILD_CONST_KEY_MAP opcode #27140)
# Python 3.6a2 3372 (MAKE_FUNCTION simplification, remove MAKE_CLOSURE
# #27095)
# Python 3.6b1 3373 (add BUILD_STRING opcode #27078)
# Python 3.6b1 3375 (add SETUP_ANNOTATIONS and STORE_ANNOTATION opcodes
# #27985)
# Python 3.6b1 3376 (simplify CALL_FUNCTIONs & BUILD_MAP_UNPACK_WITH_CALL
#27213)
# Python 3.6b1 3377 (set __class__ cell from type.__new__ #23722)
# Python 3.6b2 3378 (add BUILD_TUPLE_UNPACK_WITH_CALL #28257)
# Python 3.6rc1 3379 (more thorough __class__ validation #23722)
# Python 3.7a1 3390 (add LOAD_METHOD and CALL_METHOD opcodes #26110)
# Python 3.7a2 3391 (update GET_AITER #31709)
# Python 3.7a4 3392 (PEP 552: Deterministic pycs #31650)
# Python 3.7b1 3393 (remove STORE_ANNOTATION opcode #32550)
# Python 3.7b5 3394 (restored docstring as the first stmt in the body;
# this might affected the first line number #32911)
# Python 3.8a1 3400 (move frame block handling to compiler #17611)
# Python 3.8a1 3401 (add END_ASYNC_FOR #33041)
# Python 3.8a1 3410 (PEP570 Python Positional-Only Parameters #36540)
# Python 3.8b2 3411 (Reverse evaluation order of key: value in dict
# comprehensions #35224)
# Python 3.8b2 3412 (Swap the position of positional args and positional
# only args in ast.arguments #37593)
# Python 3.8b4 3413 (Fix "break" and "continue" in "finally" #37830)Magic Number是4字节的二进制数据，找到对应的十进制数据后，需要通过以下代码得到相应的二进制数据：
MAGIC_NUMBER = (3413).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c即：
enum PycMagic {
MAGIC_1_0 = 0x00999902,
MAGIC_1_1 = 0x00999903, /* Also covers 1.2 */
MAGIC_1_3 = 0x0A0D2E89,
MAGIC_1_4 = 0x0A0D1704,
MAGIC_1_5 = 0x0A0D4E99,
MAGIC_1_6 = 0x0A0DC4FC,
MAGIC_2_0 = 0x0A0DC687,
MAGIC_2_1 = 0x0A0DEB2A,
MAGIC_2_2 = 0x0A0DED2D,
MAGIC_2_3 = 0x0A0DF23B,
MAGIC_2_4 = 0x0A0DF26D,
MAGIC_2_5 = 0x0A0DF2B3,
MAGIC_2_6 = 0x0A0DF2D1,
MAGIC_2_7 = 0x0A0DF303,
MAGIC_3_0 = 0x0A0D0C3A,
MAGIC_3_1 = 0x0A0D0C4E,
MAGIC_3_2 = 0x0A0D0C6C,
MAGIC_3_3 = 0x0A0D0C9E,
MAGIC_3_4 = 0x0A0D0CEE,
MAGIC_3_5 = 0x0A0D0D16,
MAGIC_3_5_3 = 0x0A0D0D17,
MAGIC_3_6 = 0x0A0D0D33,
MAGIC_3_7 = 0x0A0D0D42,
MAGIC_3_8 = 0x0A0D0D55,
MAGIC_3_9 = 0x0A0D0D61,
};将版本对应的二进制码添加到pyc文件头部即可正常进行反编译。