Full unicode import system

[amauryfa]

BPO	3080
Nosy	@brettcannon, @birkenfeld, @terryjreedy, @amauryfa, @ncoghlan, @abalkin, @pitrou, @vstinner, @benjaminp, @merwok, @bitdancer, @asvetlov
Files	issue3080-5.patch issue3080.py typo.diff

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

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GitHub fields:

assignee = 'https://github.com/vstinner'
closed_at = <Date 2011-03-21.00:01:35.123>
created_at = <Date 2008-06-11.18:24:56.218>
labels = ['interpreter-core', 'type-bug']
title = 'Full unicode import system'
updated_at = <Date 2011-03-23.15:58:18.116>
user = 'https://github.com/amauryfa'

bugs.python.org fields:

activity = <Date 2011-03-23.15:58:18.116>
actor = 'vstinner'
assignee = 'vstinner'
closed = True
closed_date = <Date 2011-03-21.00:01:35.123>
closer = 'vstinner'
components = ['Interpreter Core']
creation = <Date 2008-06-11.18:24:56.218>
creator = 'amaury.forgeotdarc'
dependencies = []
files = ['20477', '21296', '21305']
hgrepos = []
issue_num = 3080
keywords = ['patch']
message_count = 60.0
messages = ['68005', '68015', '109844', '112028', '119107', '123963', '123993', '124756', '125752', '126514', '126515', '126516', '126606', '126608', '126612', '126613', '126672', '126673', '126676', '126678', '126680', '126681', '126695', '126705', '126706', '126708', '126752', '126755', '126756', '126760', '127591', '127674', '129141', '129143', '129185', '129196', '130050', '130473', '130492', '130507', '130645', '130935', '131457', '131464', '131472', '131473', '131474', '131483', '131484', '131516', '131547', '131571', '131572', '131575', '131606', '131612', '131625', '131664', '131711', '131890']
nosy_count = 14.0
nosy_names = ['brett.cannon', 'georg.brandl', 'terry.reedy', 'amaury.forgeotdarc', 'ncoghlan', 'belopolsky', 'pitrou', 'vstinner', 'benjamin.peterson', 'eric.araujo', 'Arfrever', 'r.david.murray', 'asvetlov', 'python-dev']
pr_nums = []
priority = 'high'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue3080'
versions = ['Python 3.3']

[amauryfa]

This is the most difficult part of bpo-1342:
"""
On Windows, don't use the FileSystemEncoding on Windows for sys.path items.
Instead, it should use the wide API to perform all system calls. Py3k
shouldn't ever use the file system encoding for anything on Windows.
"""

This imply to rewrite all functions in import.c, and replace all char*
arguments with unicode variables.

[benjaminp]

I suspect importlib may help with this.

[birkenfeld]

Victor is working on this.

[vstinner]

I posted a patch: bpo-9425.

[vstinner]

With bpo-8611 and bpo-9425, I patched a lot of functions and modules, including the NullImporter and zipimport, but not the core of the import machinery.

In my import_unicode SVN branch, I patched the import machinery to manipulate unicode strings, instead of bytes strings. But the patch is huge and the import machinery is fragile. Since Python 3.2 now works in a non-ASCII directory with an ASCII locale (fileystem) encoding, I don't plan to merge the patch into py3k.

The patch is still useful on Windows, because Python uses the mbcs encoding to encode/decode filenames, and this encoding is usually a very small subset of Unicode (eg. cp1252 is 256 codes wheres unicode 6.0 has 109,449 characters).

[bitdancer]

With bpo-1342 fixed, it seems that this issue is no longer critical (Haypo describes his complicated patch as "useful on Windows", but not critical. So I'm downgrading it to 'high'. Perhaps it is even 'normal'. It also seems as though it is currently languishing unless someone wants to pick it up.

[vstinner]

Haypo describes his complicated patch as "useful on Windows",
but not critical

Usecase on Windows: your japanese friend gives you an USB key (eg. created on Windows with code page 932) with his Python project, you cannot run it on your english speaking Windows (eg. code page 1252), because it loads Python modules with japanese characters in their paths.

It works if all paths are encodable to your ANSI code page. It doesn't work if a least one character of one path is not encodable to your ANSI code page.

I don't know if this usecase is common or not.

Note: the FAT file system of the USB key stores filenames as UTF-16 (and not in the user code page).

[vstinner]

Issue bpo-10785 prepares the work for this issue: store input filename as a unicode string, instead of a byte string, in the parser.

[terryjreedy]

If I edit a file with IDLE, save it, and successfully run it (perhaps to test it), then when I edit a second file that imports the first, I expect the import to work. It does not always (see bpo-10828).

Import is part of the core definition of the language. Unicode identifiers are supposedly part of Python3. Given the existence of <identifier>.py in the current directory, 'import identifier' should work. If it does not, the 3.1 message '<identifier> not found' is more truthful than the current 'no module named <identifier>', when there is one.

The doc says "identifier ::= (identifier ".")* identifier". As long as that is not true, some indication of the restriction that most people can understand would be nice. (And I suspect that a majority of Windows users, at least in the US, have no idea of what an 'ANSI code page' is.)

[vstinner]

Here is a work-in-progress patch: bpo-3080-3.patch. The patch is HUGE and written for Python 3.3.

$ diffstat issue3080-3.patch 
 Doc/c-api/module.rst   |   24 
 Include/import.h       |   73 +
 Include/moduleobject.h |    2 
 Include/pycapsule.h    |    4 
 Modules/zipimport.c    |  272 +++

---

Objects/moduleobject.c | 52 -
PC/import_nt.c | 84 +-
Python/dynload_aix.c | 2
Python/dynload_dl.c | 2
Python/dynload_hpux.c | 2
Python/dynload_next.c | 4
Python/dynload_os2.c | 2
Python/dynload_shlib.c | 2
Python/dynload_win.c | 2
Python/import.c | 1910 +++++++++++++++++++++++++++----------------------
Python/importdl.c | 79 +-
Python/importdl.h | 2
bpo-3080.py | 29
18 files changed, 1484 insertions(+), 1063 deletions(-)

As expected, most of the work in done in import.c.

Decode the module name earlier and encode it later. Try to manipulate PyUnicodeObject objects instead of char* buffers (so we have directly the string length).

Split the huge and very complex find_module() function into 3 functions (find_module, find_module_filename and find_module2) and document them. Drop OS/2 support in find_module() (it can be kept, but it was easier for me to drop it and the OS/2 maintainer wrote that Python 3 is far from being compatible with OS/2).

The patch creates some functions: PyModule_GetNameObject(), PyImport_ExecCodeModuleUnicode(), PyImport_AddModuleUnicode(), PyImport_ImportFrozenModuleUnicode(), PyModule_NewUnicode(), ...

Use "U" format to parse a module name, and "%R" to format a module name (to escape surrogates characters and add quotes, instead of "... '%.200s' ...").

PyWin_FindRegisteredModule() is now private. Remove fqname argument from _PyImport_GetDynLoadFunc(), it wasn't used.

Replace open_exclusive() by fopen(name, "wb") on Windows: is it correct?

TODO:

• rename xxxobj => xxx to keep original names and have a short patch (eg. I renamed name to nameobj during the transition to detect bugs)
• catch encoding errors in case_ok()
• don't encode in case_ok() if case_ok() does nothing (eg. on Linux)
• find a better name for find_module2()

The patch contains a tiny script, bpo-3080.py, to test the patch using an ISO-8859-1 locale.

I will open a thread on the mailing list (python-dev) to decide if this patch is needed or not. If we agree that this issue should be fixed, I will split the patch into smaller parts and start a review process.

[vstinner]

This patch changes more lines of code than my previous crazy unicode patch (msg103663, issue bpo-8242 bpo-8611 bpo-9425), but it changes less files.

[vstinner]

Oh, msg103663 was not the final patch. A more recent version of my patch for bpo-8611 / bpo-9425 is http://codereview.appspot.com/1874048:

Doc/library/sys.rst | 6
Include/Python.h | 4
Include/fileobject.h | 20
Include/import.h | 21
Include/moduleobject.h | 1
Include/sysmodule.h | 5
Include/warnings.h | 2
Lib/distutils/file_util.py | 2
Lib/platform.py | 50 +-
Lib/test/test_import.py | 7
Lib/test/test_sax.py | 5
Lib/test/test_subprocess.py | 14
Lib/test/test_sys.py | 5
Lib/test/test_urllib.py | 8
Lib/test/test_urllib2.py | 5
Lib/test/test_xml_etree.py | 6
Modules/getpath.c | 209 +++++----
Modules/main.c | 99 +++-
Modules/zipimport.c | 202 +++++----
Objects/codeobject.c | 17
Objects/fileobject.c | 32 +
Objects/moduleobject.c | 25 -
Objects/object.c | 6
Objects/typeobject.c | 12
Objects/unicodeobject.c | 11
PC/import_nt.c | 18
Parser/tokenizer.c | 12
Python/_warnings.c | 69 ++-
Python/ast.c | 16
Python/bltinmodule.c | 24 -
Python/ceval.c | 7
Python/compile.c | 14
Python/errors.c | 2
Python/import.c | 958 ++++++++++++++++++++++++++------------------
Python/importdl.c | 27 -
Python/importdl.h | 2
Python/pythonrun.c | 169 +++++++
Python/sysmodule.c | 60 ++
38 files changed, 1404 insertions(+), 748 deletions(-)

So, bpo-3080-3.patch and issue1874048_1.diff are close :-)