[Python-3000] infinite recursion with python -v

[Guido van Rossum]

I've checked a band-aid fix for this (r56878). The band-aid works by
pre-importing the latin-1 codec (and also the utf-8 codec, just to be
sure) *before* setting sys.stdout and sys.stderr (this happens in
site.py, in installnewio()).

This is a horrible hack though, and only works because, as long as
sys.stderr isn't set, the call to PyFile_WriteString() in mywrite()
(in sysmodule.c) returns a quick error, causing mywrite() to write
directly to C's stderr.

I've also checked in a change to PyFile_WriteString() to call
PyUnicode_FromString() instead of PyString_FromString(), but that
doesn't appear to make any difference (r56879).

FWIW, I've attached an edited version of the traceback mailed by Neal;
the email mangled the formatting too much. Maybe someone else has a
bright idea.

--Guido

On 8/7/07, Neal Norwitz <nnorwitz at gmail.com> wrote:
> The wiki seems to be done, so sorry for the spam.
>
> python -v crashes due to infinite recursion (well, it tried to be
> infinite until it got a stack overflow :-)  The problem seems to be
> that Lib/encodings/latin_1.py is loaded, but it tries to be converted
> to latin_1, so it tries to load the module, and ...  Or something like
> that.  See below for a call stack.
>
> Minimal version:
>
> PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches
> Lib/encodings/latin_1.py\n", f=) at Objects/fileobject.c:184
> mywrite (name= "stderr", fp=, format= "# %s matches %s\n", va=) at
> Python/sysmodule.c:1350
> PySys_WriteStderr (format= "# %s matches %s\n") at Python/sysmodule.c:1380
> check_compiled_module (pathname= "Lib/encodings/latin_1.py", mtime=,
> cpathname= "Lib/encodings/latin_1.pyc") at Python/import.c:755
> load_source_module (name= "encodings.latin_1", pathname=
> "Lib/encodings/latin_1.py", fp=) at Python/import.c:938
> load_module (name= "encodings.latin_1", fp=,buf=
> "Lib/encodings/latin_1.py", type=1, loader=) at Python/import.c:1733
> import_submodule (mod=, subname= "latin_1",fullname=
> "encodings.latin_1") at Python/import.c:2418
> load_next (mod=,altmod=, p_name=,buf= "encodings.latin_1", p_buflen=)
> at Python/import.c:2213
> import_module_level (name=, globals=, locals=, fromlist=, level=0) at
> Python/import.c:1992
> PyImport_ImportModuleLevel (name= "encodings.latin_1", globals=,
> locals=, fromlist=, level=0) at Python/import.c:2056
> builtin___import__ () at Python/bltinmodule.c:151
> [...]
> _PyCodec_Lookup (encoding= "latin-1") at Python/codecs.c:147
> codec_getitem (encoding= "latin-1",index=0) at Python/codecs.c:211
> PyCodec_Encoder (encoding= "latin-1") at Python/codecs.c:275
> PyCodec_Encode (object=,encoding= "latin-1", errors=) at Python/codecs.c:322
> PyString_AsEncodedObject (str=,encoding= "latin-1", errors=) at
> Objects/stringobject.c:459
> string_encode () at Objects/stringobject.c:3138
> [...]
> PyFile_WriteObject (v=, f=, flags=1) at Objects/fileobject.c:159
> PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches
> Lib/encodings/latin_1.py\n",f=) at Objects/fileobject.c:184
>
> == Stack trace for python -v recursion (argument values are mostly trimmed) ==
>
> PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches
> Lib/encodings/latin_1.py\n", f=) at Objects/fileobject.c:184
> mywrite (name= "stderr", fp=, format= "# %s matches %s\n", va=) at
> Python/sysmodule.c:1350
> PySys_WriteStderr (format= "# %s matches %s\n") at Python/sysmodule.c:1380
> check_compiled_module (pathname= "Lib/encodings/latin_1.py", mtime=,
> cpathname= "Lib/encodings/latin_1.pyc") at Python/import.c:755
> load_source_module (name= "encodings.latin_1", pathname=
> "Lib/encodings/latin_1.py", fp=) at Python/import.c:938
> load_module (name= "encodings.latin_1", fp=,buf=
> "Lib/encodings/latin_1.py", type=1, loader=) at Python/import.c:1733
> import_submodule (mod=, subname= "latin_1",fullname=
> "encodings.latin_1") at Python/import.c:2418
> load_next (mod=,altmod=, p_name=,buf= "encodings.latin_1", p_buflen=)
> at Python/import.c:2213
> import_module_level (name=, globals=, locals=, fromlist=, level=0) at
> Python/import.c:1992
> PyImport_ImportModuleLevel (name= "encodings.latin_1", globals=,
> locals=, fromlist=, level=0) at Python/import.c:2056
> builtin___import__ () at Python/bltinmodule.c:151
> PyCFunction_Call () at Objects/methodobject.c:77
> PyObject_Call () at Objects/abstract.c:1736
> do_call () at Python/ceval.c:3764
> call_function (pp_stack=, oparg=513) at Python/ceval.c:3574
> PyEval_EvalFrameEx (f=, throwflag=0) at Python/ceval.c:2216
> PyEval_EvalCodeEx () at Python/ceval.c:2835
> function_call () at Objects/funcobject.c:634
> PyObject_Call () at Objects/abstract.c:1736
> PyEval_CallObjectWithKeywords () at Python/ceval.c:3431
> _PyCodec_Lookup (encoding= "latin-1") at Python/codecs.c:147
> codec_getitem (encoding= "latin-1",index=0) at Python/codecs.c:211
> PyCodec_Encoder (encoding= "latin-1") at Python/codecs.c:275
> PyCodec_Encode (object=,encoding= "latin-1", errors=) at Python/codecs.c:322
> PyString_AsEncodedObject (str=,encoding= "latin-1", errors=) at
> Objects/stringobject.c:459
> string_encode () at Objects/stringobject.c:3138
> PyCFunction_Call () at Objects/methodobject.c:73
> call_function () at Python/ceval.c:3551
> PyEval_EvalFrameEx (f=, throwflag=0) at Python/ceval.c:2216
> PyEval_EvalCodeEx () at Python/ceval.c:2835
> function_call () at Objects/funcobject.c:634
> PyObject_Call () at Objects/abstract.c:1736
> method_call () at Objects/classobject.c:397
> PyObject_Call () at Objects/abstract.c:1736
> PyEval_CallObjectWithKeywords () at Python/ceval.c:3431
> PyFile_WriteObject (v=, f=, flags=1) at Objects/fileobject.c:159
> PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches
> Lib/encodings/latin_1.py\n",f=) at Objects/fileobject.c:184
> _______________________________________________
> Python-3000 mailing list
> Python-3000 at python.org
> http://mail.python.org/mailman/listinfo/python-3000
> Unsubscribe: http://mail.python.org/mailman/options/python-3000/guido%40python.org
>


-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)
-------------- next part --------------
short:

PyFile_WriteString (s="# Lib/encodings/latin_1.pyc matches Lib/encodings/latin_1.py\n", f=) at Objects/fileobject.c:184
mywrite (name="stderr", fp=, format="# %s matches %s\n", va=) at Python/sysmodule.c:1350
PySys_WriteStderr (format="# %s matches %s\n") at Python/sysmodule.c:1380
check_compiled_module (pathname="Lib/encodings/latin_1.py", mtime=, cpathname="Lib/encodings/latin_1.pyc") at Python/import.c:755
load_source_module (name="encodings.latin_1", pathname="Lib/encodings/latin_1.py", fp=) at Python/import.c:938
load_module (name="encodings.latin_1", fp=,buf="Lib/encodings/latin_1.py", type=1, loader=) at Python/import.c:1733
import_submodule (mod=, subname="latin_1",fullname="encodings.latin_1") at Python/import.c:2418
load_next (mod=,altmod=, p_name=,buf="encodings.latin_1", p_buflen=) at Python/import.c:2213
import_module_level (name=, globals=, locals=, fromlist=, level=0) at Python/import.c:1992
PyImport_ImportModuleLevel (name="encodings.latin_1", globals=, locals=, fromlist=, level=0) at Python/import.c:2056
builtin___import__ () at Python/bltinmodule.c:151
[...]
_PyCodec_Lookup (encoding="latin-1") at Python/codecs.c:147
codec_getitem (encoding="latin-1",index=0) at Python/codecs.c:211
PyCodec_Encoder (encoding="latin-1") at Python/codecs.c:275
PyCodec_Encode (object=,encoding="latin-1", errors=) at Python/codecs.c:322
PyString_AsEncodedObject (str=,encoding="latin-1", errors=) at Objects/stringobject.c:459
string_encode () at Objects/stringobject.c:3138
[...]
PyFile_WriteObject (v=, f=, flags=1) at Objects/fileobject.c:159
PyFile_WriteString (s="# Lib/encodings/latin_1.pyc matches Lib/encodings/latin_1.py\n",f=) at Objects/fileobject.c:184




long:

PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches Lib/encodings/latin_1.py\n", f=) at Objects/fileobject.c:184
mywrite (name= "stderr", fp=, format= "# %s matches %s\n", va=) at Python/sysmodule.c:1350
PySys_WriteStderr (format= "# %s matches %s\n") at Python/sysmodule.c:1380
check_compiled_module (pathname= "Lib/encodings/latin_1.py", mtime=, cpathname= "Lib/encodings/latin_1.pyc") at Python/import.c:755
load_source_module (name= "encodings.latin_1", pathname= "Lib/encodings/latin_1.py", fp=) at Python/import.c:938
load_module (name= "encodings.latin_1", fp=,buf= "Lib/encodings/latin_1.py", type=1, loader=) at Python/import.c:1733
import_submodule (mod=, subname= "latin_1",fullname= "encodings.latin_1") at Python/import.c:2418
load_next (mod=,altmod=, p_name=,buf= "encodings.latin_1", p_buflen=) at Python/import.c:2213
import_module_level (name=, globals=, locals=, fromlist=, level=0) at Python/import.c:1992
PyImport_ImportModuleLevel (name= "encodings.latin_1", globals=, locals=, fromlist=, level=0) at Python/import.c:2056
builtin___import__ () at Python/bltinmodule.c:151
PyCFunction_Call () at Objects/methodobject.c:77
PyObject_Call () at Objects/abstract.c:1736
do_call () at Python/ceval.c:3764
call_function (pp_stack=, oparg=513) at Python/ceval.c:3574
PyEval_EvalFrameEx (f=, throwflag=0) at Python/ceval.c:2216
PyEval_EvalCodeEx () at Python/ceval.c:2835
function_call () at Objects/funcobject.c:634
PyObject_Call () at Objects/abstract.c:1736
PyEval_CallObjectWithKeywords () at Python/ceval.c:3431
_PyCodec_Lookup (encoding= "latin-1") at Python/codecs.c:147
codec_getitem (encoding= "latin-1",index=0) at Python/codecs.c:211
PyCodec_Encoder (encoding= "latin-1") at Python/codecs.c:275
PyCodec_Encode (object=,encoding= "latin-1", errors=) at Python/codecs.c:322
PyString_AsEncodedObject (str=,encoding= "latin-1", errors=) at Objects/stringobject.c:459
string_encode () at Objects/stringobject.c:3138
PyCFunction_Call () at Objects/methodobject.c:73
call_function () at Python/ceval.c:3551
PyEval_EvalFrameEx (f=, throwflag=0) at Python/ceval.c:2216
PyEval_EvalCodeEx () at Python/ceval.c:2835
function_call () at Objects/funcobject.c:634
PyObject_Call () at Objects/abstract.c:1736
method_call () at Objects/classobject.c:397
PyObject_Call () at Objects/abstract.c:1736
PyEval_CallObjectWithKeywords () at Python/ceval.c:3431
PyFile_WriteObject (v=, f=, flags=1) at Objects/fileobject.c:159
PyFile_WriteString (s= "# Lib/encodings/latin_1.pyc matches Lib/encodings/latin_1.py\n",f=) at Objects/fileobject.c:184