[Python-Dev] PEP 432 progress: Python initalization

[Victor Stinner]

Hi,

FYI I pushed a new change related to the PEP 432: it becomes possible
to skip completely the calculation of paths, especially sys.path. If
you fill "Path configuration outputs" fileds of PyCoreConfig (see
below), _PyPathConfig_Init() should not be called.

It should be helpful for some users when Python is embedded. Sadly,
this feature will not be exposed before Python 3.8, PEP 432 APIs are
currently private.

_PyCoreConfig structure contains most parameters (not all yet) needed
by Py_Initialize().

typedef struct {
    int install_signal_handlers;  /* Install signal handlers? -1 means unset */

    int ignore_environment; /* -E, Py_IgnoreEnvironmentFlag */
    int use_hash_seed;      /* PYTHONHASHSEED=x */
    unsigned long hash_seed;
    const char *allocator;  /* Memory allocator: _PyMem_SetupAllocators() */
    int dev_mode;           /* PYTHONDEVMODE, -X dev */
    int faulthandler;       /* PYTHONFAULTHANDLER, -X faulthandler */
    int tracemalloc;        /* PYTHONTRACEMALLOC, -X tracemalloc=N */
    int import_time;        /* PYTHONPROFILEIMPORTTIME, -X importtime */
    int show_ref_count;     /* -X showrefcount */
    int show_alloc_count;   /* -X showalloccount */
    int dump_refs;          /* PYTHONDUMPREFS */
    int malloc_stats;       /* PYTHONMALLOCSTATS */
    int coerce_c_locale;    /* PYTHONCOERCECLOCALE, -1 means unknown */
    int coerce_c_locale_warn; /* PYTHONCOERCECLOCALE=warn */
    int utf8_mode;          /* PYTHONUTF8, -X utf8; -1 means unknown */

    wchar_t *program_name;  /* Program name, see also Py_GetProgramName() */
    int argc;               /* Number of command line arguments,
                               -1 means unset */
    wchar_t **argv;         /* Command line arguments */
    wchar_t *program;       /* argv[0] or "" */

    int nxoption;           /* Number of -X options */
    wchar_t **xoptions;     /* -X options */

    int nwarnoption;        /* Number of warnings options */
    wchar_t **warnoptions;  /* Warnings options */

    /* Path configuration inputs */
    wchar_t *module_search_path_env; /* PYTHONPATH environment variable */
    wchar_t *home;          /* PYTHONHOME environment variable,
                               see also Py_SetPythonHome(). */

    /* Path configuration outputs */
    int nmodule_search_path;        /* Number of sys.path paths,
                                       -1 means unset */
    wchar_t **module_search_paths;  /* sys.path paths */
    wchar_t *executable;    /* sys.executable */
    wchar_t *prefix;        /* sys.prefix */
    wchar_t *base_prefix;   /* sys.base_prefix */
    wchar_t *exec_prefix;   /* sys.exec_prefix */
    wchar_t *base_exec_prefix;  /* sys.base_exec_prefix */

    /* Private fields */
    int _disable_importlib; /* Needed by freeze_importlib */
} _PyCoreConfig;

and

typedef struct {
    int install_signal_handlers;   /* Install signal handlers? -1 means unset */
    PyObject *argv;                /* sys.argv list, can be NULL */
    PyObject *executable;          /* sys.executable str */
    PyObject *prefix;              /* sys.prefix str */
    PyObject *base_prefix;         /* sys.base_prefix str, can be NULL */
    PyObject *exec_prefix;         /* sys.exec_prefix str */
    PyObject *base_exec_prefix;    /* sys.base_exec_prefix str, can be NULL */
    PyObject *warnoptions;         /* sys.warnoptions list, can be NULL */
    PyObject *xoptions;            /* sys._xoptions dict, can be NULL */
    PyObject *module_search_path;  /* sys.path list */
} _PyMainInterpreterConfig;

Victor