bpo-40228: More robust frame.setlineno. #19437
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Objects/frameobject.c
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| #define BITS_PER_BLOCK 3 | ||
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| static inline int64_t | ||
| push_block(int64_t stack, Kind kind) { |
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Please put the { on its own line (PEP 7).
| if (tracker->addr >= tracker->code_len) { | ||
| return -1; | ||
| } | ||
| int *linestarts = PyMem_New(int, len); |
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Please check this call for failure.
Objects/frameobject.c
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| return -1; | ||
| } | ||
| int *linestarts = PyMem_New(int, len); | ||
| Py_ssize_t size = PyBytes_Size(code->co_lnotab) / 2; |
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Please use PyBytes_GET_SIZE() here instead of PyBytes_Size().
| PyErr_Format(PyExc_ValueError, | ||
| "line %d comes after the current code block", | ||
| (int)l_new_lineno); | ||
| return -1; |
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lines is leaked here.
Objects/frameobject.c
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| if (tracker.code[f->f_lasti] == YIELD_VALUE || tracker.code[f->f_lasti] == YIELD_FROM) { | ||
| PyErr_SetString(PyExc_ValueError, | ||
| "can't jump from a 'yield' statement"); | ||
| int len = PyBytes_Size(f->f_code->co_code)/sizeof(_Py_CODEUNIT); |
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Please use PyBytes_GET_SIZE().
Objects/frameobject.c
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| tracker->line -= (signed char)tracker->lnotab[tracker->offset+1]; | ||
| } | ||
| } | ||
| const _Py_CODEUNIT *code = (const _Py_CODEUNIT *)PyBytes_AsString(code_obj->co_code); |
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PyBytes_AS_STRING().
PEP 7 states that no line should be longer than 79 characters.
Objects/frameobject.c
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| } | ||
| int *linestarts = PyMem_New(int, len); | ||
| Py_ssize_t size = PyBytes_Size(code->co_lnotab) / 2; | ||
| unsigned char *p = (unsigned char*)PyBytes_AsString(code->co_lnotab); |
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@ZackerySpytz thanks for the review |
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Re-basing to force test re-run before merging. |
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Makes no assumptions about the layout of bytecode.
Makes setting
frame.f_linenomore robust and flexible.To improve robustness, the code takes the simple, pragmatic approach: If it is safe to make the jump, then do so. We no longer attempt to decide if it "reasonable" or "sensible", merely if it is safe.
"Safe" in this context, means "won't crash the interpreter".
The increased flexibility is a side effect of this more pragmatic approach.
There are number of test cases where a jump is safe, but we disallowed it. Those cases are now allowed.
A couple of cases are now disallowed. Those involve jumping to unreachable code. Since we cannot compute the exception stack state for unreachable code, it is unsafe to jump to it.
Removing assumptions about the bytecode layout will allow us to enhance the compiler without worrying about breaking this code all the time.
Another point in favour of this PR is that it reduces the code size by about 80 lines.
https://bugs.python.org/issue40228