[Python-ideas] PEP 432: Simplifying the CPython startup sequence

[Christian Heimes]

Am 27.12.2012 16:10, schrieb Nick Coghlan:

> Additional configuration is handled via separate API calls::
> 
>     Py_SetProgramName() (call before Py_Initialize())
>     Py_SetPath() (optional, call before Py_Initialize())
>     Py_SetPythonHome() (optional, call before Py_Initialize()???)
>     Py_SetArgv[Ex]() (call after Py_Initialize())

[...]

> The only configuration that currently absolutely needs to be in place
> before even the interpreter core can be initialised is the seed for the
> randomised hash algorithm. However, there are a couple of settings needed
> there: whether or not hash randomisation is enabled at all, and if it's
> enabled, whether or not to use a specific seed value.
> 
> The proposed API for this step in the startup sequence is::
> 
>     void Py_BeginInitialization(Py_CoreConfig *config);
> 
> Like Py_Initialize, this part of the new API treats initialisation failures
> as fatal errors. While that's still not particularly embedding friendly,
> the operations in this step *really* shouldn't be failing, and changing them
> to return error codes instead of aborting would be an even larger task than
> the one already being proposed.
> 
> The new Py_CoreConfig struct holds the settings required for preliminary
> configuration::
> 
>     typedef struct {
>         int use_hash_seed;
>         size_t hash_seed;
>     } Py_CoreConfig;

Hello Nick,

we could use the opportunity and move more settings to Py_CoreConfig. At
the moment several settings are stored in static variables:

Python/pythonrun.c

static wchar_t *progname
static wchar_t *default_home
static wchar_t env_home[PATH_MAX+1]

Modules/getpath.c

static wchar_t prefix[MAXPATHLEN+1]
static wchar_t exec_prefix[MAXPATHLEN+1]
static wchar_t progpath[MAXPATHLEN+1]
static wchar_t *module_search_path
static int module_search_path_malloced
static wchar_t *lib_python = L"lib/python" VERSION;

PC/getpath.c

static wchar_t dllpath[MAXPATHLEN+1]


These settings could be added to the Py_CoreConfig struct and unify the
configuration schema for embedders. Functions like Py_SetProgramName()
would set the members of a global Py_CoreConfig struct.

Christian