Derby #9: Convert 52 sites to Argument Clinic across 11 files

[larryhastings]

BPO	20178
Nosy	@larryhastings, @meadori, @berkerpeksag, @serhiy-storchaka, @erlend-aasland
Files	issue20178-cyptes-01.patch issue20178-sqlite-01.patch issue20178-cyptes-02.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = 'https://github.com/meadori'
closed_at = None
created_at = <Date 2014-01-08.00:14:38.886>
labels = ['extension-modules', 'type-feature', '3.8', 'expert-argument-clinic']
title = 'Derby #9: Convert 52 sites to Argument Clinic across 11 files'
updated_at = <Date 2021-06-22.22:57:35.751>
user = 'https://github.com/larryhastings'

bugs.python.org fields:

activity = <Date 2021-06-22.22:57:35.751>
actor = 'erlendaasland'
assignee = 'meador.inge'
closed = False
closed_date = None
closer = None
components = ['Extension Modules', 'Argument Clinic']
creation = <Date 2014-01-08.00:14:38.886>
creator = 'larry'
dependencies = []
files = ['33438', '33470', '39296']
hgrepos = []
issue_num = 20178
keywords = ['patch']
message_count = 14.0
messages = ['207634', '207740', '208000', '208001', '208130', '208186', '208187', '208381', '208414', '224759', '242607', '242649', '324851', '396373']
nosy_count = 5.0
nosy_names = ['larry', 'meador.inge', 'berker.peksag', 'serhiy.storchaka', 'erlendaasland']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue20178'
versions = ['Python 3.8']

[larryhastings]

This issue is part of the Great Argument Clinic Conversion Derby,
where we're trying to convert as much of Python 3.4 to use
Argument Clinic as we can before Release Candidate 1 on January 19.

This issue asks you to change the following bundle of files:
Modules/_ctypes/_ctypes.c: 8 sites
Modules/_ctypes/_ctypes_test.c: 1 sites
Modules/_ctypes/callproc.c: 14 sites
Modules/_ctypes/stgdict.c: 0 sites
Modules/_curses_panel.c: 3 sites
Modules/_sqlite/cache.c: 1 sites
Modules/_sqlite/connection.c: 12 sites
Modules/_sqlite/cursor.c: 5 sites
Modules/_sqlite/microprotocols.c: 1 sites
Modules/_sqlite/module.c: 6 sites
Modules/_sqlite/row.c: 1 sites

Talk to me (larry) if you only want to attack part of a bundle.

For instructions on how to convert a function to work with Argument
Clinic, read the "howto":
http://docs.python.org/dev/howto/clinic.html

[meadori]

I will pick this one up.

[meadori]

Larry, the attached patch converts what is convertible of
Modules/_ctypes/_ctypes. Although, I ran into an odd case
with this conversion: the converted functions are each used
in *multiple* PyMethodDef tables. So while clinic can generate
equivalent code, the builtins are not all pinned to one type.
The type I pinned it to is the same type that the methods
are documented against:
http://docs.python.org/2/library/ctypes.html#ctypes.\_CData

Since clinic makes you explicitly specify the fully qualified method
name, I assume sharing like this is not allowed.

Thoughts?

[meadori]

None of the sites in Modules/_curses_panel.c look convertible.

[meadori]

Attached is a first cut for sqlite3. It is generally OK, but I have the following
nits:

* As is probably expected, __init__ and __call__ procs can't be converted.

* sqlite3.Connection.{execute, executemany, executescript} don't use
  PyArg_Parse*.

* The clinic version of 'sqlite3.adapt' has an argument string of "O|OO".
  The first optional parameter defaults to 'pysqlite_PrepareProtocolType'
  in C and 'sqlite3.ProtocolType' in Python.  However, I don't know how to
  represent the Python value because Python default values are 'eval'd by
  clinic *and* the 'sqlite3' module is not imported for the eval.

* The clinic version of 'sqlite3.Cursor.fetchmany' has an arguments string
  of "|i".  The first parameter defaults to
  '((pysqlite_Cursor *)self)->arraysize' in C and 'self.arraysize' in
  Python.  I don't know how to express the Python initialization.

* 'sqlite3.complete' uses 'as module_complete' because 'sqlite3_complete'
  is a public SQLite API function: http://www.sqlite.org/c3ref/complete.html.
  I used 'as' on all the other functions in 'module.c' as well.  Mainly
  for local consistency.

* '_pysqlite_query_execute' required a little refactoring due to the fact
  that it is a utility function used to implement 'sqlite3.Cursor.execute'
  and 'sqlite3.Cursor.executemany'.  'PyArg_ParseTuple' was being called in
  different way depending on a control parameter.

* I didn't convert 'sqlite3.Cursor.setinputsizes' and
  'sqlite3.Cursor.setoutputsize' because they share a docstring and
  simple no-op method def.

* I didn't convert 'sqlite.connect' because it would have required packaing
  the arguments back up to pass to 'PyObject_Call'.

[larryhastings]

In the past few days I added "cloning" functions, which lets you reuse the parameters and return converter from an existing function. That might help with Modules/_ctypes/_ctypes.

[larryhastings]

All the functions in curses_panel are convertable. The threeMETH_NOARGS functions simply get no arguments. And here's new_panel:

new_panel
window: object(subclass_of='&PyCursesWindow_Type')
/

[larryhastings]

Meador: I'm going to change Argument Clinic so you can get the "args" and "kwargs" values passed in to the impl. That's issue bpo-20291; I already added you to it "nosy" list. With that change in you'll be able to convert "sqlite3.connect".

[larryhastings]

Larry Hastings added the comment:

• As is probably expected, __init__ and __call__ procs
  can't be converted.

I should have a fix in for __init__ and __call__ later today. (Issue bpo-20294.)
For the record, you could convert them, you just had to wrap the parsing function
to deal with the return type difference, and *args / **kwargs might be tricky too.

* sqlite3.Connection.{execute, executemany, executescript} don't use
  PyArg_Parse*.

In the next few days I'm going to add support for "*args" and "**kwargs", and
then you'll be able to convert these functions. (Issue bpo-20291.) Again, even
if Argument Clinic doesn't do any parsing, it's still helpful to have it
generate signatures.

* The clinic version of 'sqlite3.adapt' has an argument string of "O|OO".
  The first optional parameter defaults to 'pysqlite_PrepareProtocolType'
  in C and 'sqlite3.ProtocolType' in Python.  However, I don't know how to
  represent the Python value because Python default values are 'eval'd by
  clinic \*and* the 'sqlite3' module is not imported for the eval.

You'll be able to do this soon:

parameter: object(c_default='pysqlite_PrepareProtocolType') = ProtocolType

This feature isn't checked in yet, I'm waiting for a review. It's part of
bpo-20226, which I guess you already noticed.

• The clinic version of 'sqlite3.Cursor.fetchmany' has an arguments string
  of "|i". The first parameter defaults to
  '((pysqlite_Cursor *)self)->arraysize' in C and 'self.arraysize' in
  Python. I don't know how to express the Python initialization.

You can't. How about you use a default of -1 and then:

if (maxrows == -1)
maxrows = self->arraysize

• I didn't convert 'sqlite3.Cursor.setinputsizes' and
  'sqlite3.Cursor.setoutputsize' because they share a docstring and
  simple no-op method def.

I'd prefer it if you converted them anyway. Converting them means they'll
have signature information which is an unconditional good.

• I didn't convert 'sqlite.connect' because it would have required
  packaing the arguments back up to pass to 'PyObject_Call'.

Once I add the ability to pass in *args and **kwargs, you'll be able to
convert sqlite.connect.

I think I responded to all your other comments when I reviewed the patch.

Thanks!

[larryhastings]

All the Derby patches should only go into trunk at this point.

[serhiy-storchaka]

bpo-20178-cyptes-01.patch is outdated due to changes in Argument Clinic and ctypes. Here is updated and extended patch.

[serhiy-storchaka]

For Modules/_curses_panel.c there is special issue, bpo-20171, with the patch.

bpo-20178-sqlite-01.patch is applied almost clearly, but due to changes to Argument Clinic it should be updated. Perhaps more functions can be converted (functions that don't use PyArg_Parse* are worth to be converted too).

[berkerpeksag]

I'm working on converting Modules/_sqlite/* to Argument Clinic.

[erlend-aasland]

FYI, sqlite3 was converted to Argument Clinic in bpo-40956.