In development mode and in debug build, encoding and errors arguments
are now checked on string encoding and decoding operations. Examples:
open(), str.encode() and bytes.decode().
By default, for best performances, the errors argument is only
checked at the first encoding/decoding error, and the encoding
argument is sometimes ignored for empty strings.
Release build and debug build are now ABI compatible: the Py_DEBUG
define no longer implies Py_TRACE_REFS define which introduces the
only ABI incompatibility.
A new "./configure --with-trace-refs" build option is now required to
get Py_TRACE_REFS define which adds sys.getobjects() function and
PYTHONDUMPREFS environment variable.
Changes:
* Add ./configure --with-trace-refs
* Py_DEBUG no longer implies Py_TRACE_REFS
In development mode (-X dev) and in debug build, the io.IOBase
destructor now logs close() exceptions. These exceptions are silent
by default in release mode.
* Revert "bpo-34589: Add -X coerce_c_locale command line option (GH-9378)"
This reverts commit dbdee0073c.
* Revert "bpo-34589: C locale coercion off by default (GH-9073)"
This reverts commit 7a0791b699.
* Revert "bpo-34589: Make _PyCoreConfig.coerce_c_locale private (GH-9371)"
This reverts commit 188ebfa475.
In some development setups it is inconvenient or impossible to write bytecode
caches to the code tree, but the bytecode caches are still useful. The
PYTHONPYCACHEPREFIX environment variable allows specifying an alternate
location for cached bytecode files, within which a directory tree mirroring the code
tree will be created. This cache tree is then used (for both reading and writing)
instead of the local `__pycache__` subdirectory within each source directory.
Exposed at runtime as sys.pycache_prefix (defaulting to None), and can
be set from the CLI as "-X pycache_prefix=path".
Patch by Carl Meyer.
While locale coercion and UTF-8 mode turned out to
be complementary ideas rather than competing ones,
it isn't immediately obvious why it's useful to
have both, or how they interact at runtime.
This updates both the Python 3.7 What's New doc
and the PYTHONCOERCECLOCALE and PYTHONUTF8
documentation in an attempt to clarify that
relationship:
- in the respective What's New sections, add a closing paragraph
explaining which problem each one solves, and pointing to the
other PEP's section for the specific aspects it relies on the other
PEP to solve
- use "locale-aware mode" as a more descriptive term for the
default non-UTF-8 mode
- improve wording conistenccy between the PYTHONCOERCECLOCALE
and PYTHONUTF8 docs when they cover the same thing (mostly
related to legacy locale detection and setting the standard
stream error handler)
- improve the description of the locale coercion trigger conditions
(including pointing out that setting LC_ALL turns off locale coercion)
- port the full description of the UTF-8 mode behaviour changes
from PEP 540 into the PYTHONUTF8 documentation
- be explicit that PYTHONIOENCODING still overrides the settings
for the standard streams
- mention concrete examples of things that do and don't get their
text encoding assumptions adjusted by the two text encoding
assumption override techniques
- primary change is to add a new default filter entry for
'default::DeprecationWarning:__main__'
- secondary change is an internal one to cope with plain
strings in the warning module's internal filter list
(this avoids the need to create a compiled regex object
early on during interpreter startup)
- assorted documentation updates, including many more
examples of configuring the warnings settings
- additional tests to ensure that both the pure Python and
the C accelerated warnings modules have the expected
default configuration
bpo-29240, bpo-32030: If the encoding change (C locale coerced or
UTF-8 Mode changed), Py_Main() now reads again the configuration with
the new encoding.
Changes:
* Add _Py_UnixMain() called by main().
* Rename pymain_free_pymain() to pymain_clear_pymain(), it can now be
called multipled times.
* Rename pymain_parse_cmdline_envvars() to pymain_read_conf().
* Py_Main() now clears orig_argc and orig_argv at exit.
* Remove argv_copy2, Py_Main() doesn't modify argv anymore. There is
no need anymore to get two copies of the wchar_t** argv.
* _PyCoreConfig: add coerce_c_locale and coerce_c_locale_warn.
* Py_UTF8Mode is now initialized to -1.
* Locale coercion (PEP 538) now respects -I and -E options.
bpo-32329, bpo-32030:
* The -R option now turns on hash randomization when the
PYTHONHASHSEED environment variable is set to 0 Previously, the
option was ignored.
* sys.flags.hash_randomization is now properly set to 0 when hash
randomization is turned off by PYTHONHASHSEED=0.
* _PyCoreConfig_ReadEnv() now reads the PYTHONHASHSEED environment
variable. _Py_HashRandomization_Init() now only apply the
configuration, it doesn't read PYTHONHASHSEED anymore.
* Add -X utf8 command line option, PYTHONUTF8 environment variable
and a new sys.flags.utf8_mode flag.
* If the LC_CTYPE locale is "C" at startup: enable automatically the
UTF-8 mode.
* Add _winapi.GetACP(). encodings._alias_mbcs() now calls
_winapi.GetACP() to get the ANSI code page
* locale.getpreferredencoding() now returns 'UTF-8' in the UTF-8
mode. As a side effect, open() now uses the UTF-8 encoding by
default in this mode.
* Py_DecodeLocale() and Py_EncodeLocale() now use the UTF-8 encoding
in the UTF-8 Mode.
* Update subprocess._args_from_interpreter_flags() to handle -X utf8
* Skip some tests relying on the current locale if the UTF-8 mode is
enabled.
* Add test_utf8mode.py.
* _Py_DecodeUTF8_surrogateescape() gets a new optional parameter to
return also the length (number of wide characters).
* pymain_get_global_config() and pymain_set_global_config() now
always copy flag values, rather than only copying if the new value
is greater than the old value.
Rather than supporting dev mode directly in the warnings module, this
instead adjusts the initialisation code to add an extra 'default'
entry to sys.warnoptions when dev mode is enabled.
This ensures that dev mode behaves *exactly* as if `-Wdefault` had
been passed on the command line, including in the way it interacts
with `sys.warnoptions`, and with other command line flags like `-bb`.
Fix also bpo-20361: have -b & -bb options take precedence over any
other warnings options.
Patch written by Nick Coghlan, with minor modifications of Victor Stinner.
Python now supports checking bytecode cache up-to-dateness with a hash of the
source contents rather than volatile source metadata. See the PEP for details.
While a fairly straightforward idea, quite a lot of code had to be modified due
to the pervasiveness of pyc implementation details in the codebase. Changes in
this commit include:
- The core changes to importlib to understand how to read, validate, and
regenerate hash-based pycs.
- Support for generating hash-based pycs in py_compile and compileall.
- Modifications to our siphash implementation to support passing a custom
key. We then expose it to importlib through _imp.
- Updates to all places in the interpreter, standard library, and tests that
manually generate or parse pyc files to grok the new format.
- Support in the interpreter command line code for long options like
--check-hash-based-pycs.
- Tests and documentation for all of the above.
* bpo-32101: Add sys.flags.dev_mode flag
Rename also the "Developer mode" to the "Development mode".
* bpo-32101: Add PYTHONDEVMODE environment variable
Mention it in the development chapiter.
* Fix _PyMem_SetupAllocators("debug"): always restore allocators to
the defaults, rather than only caling _PyMem_SetupDebugHooks().
* Add _PyMem_SetDefaultAllocator() helper to set the "default"
allocator.
* Add _PyMem_GetAllocatorsName(): get the name of the allocators
* main() now uses debug hooks on memory allocators if Py_DEBUG is
defined, rather than calling directly malloc()
* Document default memory allocators in C API documentation
* _Py_InitializeCore() now fails with a fatal user error if
PYTHONMALLOC value is an unknown memory allocator, instead of
failing with a fatal internal error.
* Add new tests on the PYTHONMALLOC environment variable
* Add support.with_pymalloc()
* Add the _testcapi.WITH_PYMALLOC constant and expose it as
support.with_pymalloc().
* sysconfig.get_config_var('WITH_PYMALLOC') doesn't work on Windows, so
replace it with support.with_pymalloc().
* pythoninfo: add _testcapi collector for pymem
The developer mode (-X dev) now creates all default warnings filters
to order filters in the correct order to always show ResourceWarning
and make BytesWarning depend on the -b option.
Write a functional test to make sure that ResourceWarning is logged
twice at the same location in the developer mode.
Add a new 'dev_mode' field to _PyCoreConfig.
Add a new "developer mode": new "-X dev" command line option to
enable debug checks at runtime.
Changes:
* Add unit tests for -X dev
* test_cmd_line: replace test.support with support.
* Fix _PyRuntimeState_Fini(): Use the same memory allocator
than _PyRuntimeState_Init().
* Fix _PyMem_GetDefaultRawAllocator()
- removes PY_WARN_ON_C_LOCALE build time flag
- locale coercion and compatibility warnings are now always compiled
in, but are off by default
- adds PYTHONCOERCECLOCALE=warn runtime option to aid in
debugging potentially locale related compatibility problems
Due to not-yet-resolved test failures on *BSD systems (including
Mac OS X), this also temporarily disables UTF-8 as a locale coercion
target, and skips testing the interpreter's behavior in the POSIX locale.
- new PYTHONCOERCECLOCALE config setting
- coerces legacy C locale to C.UTF-8, C.utf8 or UTF-8 by default
- always uses C.UTF-8 on Android
- uses `surrogateescape` on stdin and stdout in the coercion
target locales
- configure option to disable locale coercion at build time
- configure option to disable C locale warning at build time
* Cannot seem to link directly to main options from the “unittest” module,
because that module has its own set of options
* Mask out linking for options that no longer exist in Python 3
SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off by default. It can
be re-enabled using the "-X showalloccount" option. It now outputs to stderr
instead of stdout.
Issue #26249: PyMem_Malloc() allocator family now uses the pymalloc allocator
rather than system malloc(). Applications calling PyMem_Malloc() without
holding the GIL can now crash: use PYTHONMALLOC=debug environment variable to
validate the usage of memory allocators in your application.
Issue #26516:
* Add PYTHONMALLOC environment variable to set the Python memory
allocators and/or install debug hooks.
* PyMem_SetupDebugHooks() can now also be used on Python compiled in release
mode.
* The PYTHONMALLOCSTATS environment variable can now also be used on Python
compiled in release mode. It now has no effect if set to an empty string.
* In debug mode, debug hooks are now also installed on Python memory allocators
when Python is configured without pymalloc.
The previous fix only handled the case of the parent package of __main__
failing to initialize.
Also make the "Error while finding spec" formatting slightly more appealing,
and document and test that the module name must be absolute.
The concept of .pyo files no longer exists. Now .pyc files have an
optional `opt-` tag which specifies if any extra optimizations beyond
the peepholer were applied.
Add also a PYTHONASYNCIODEBUG environment variable to debug coroutines since
Python startup, to be able to debug coroutines defined directly in the asyncio
module.
-I
Run Python in isolated mode. This also implies -E and -s. In isolated mode
sys.path contains neither the script’s directory nor the user’s
site-packages directory. All PYTHON* environment variables are ignored,
too. Further restrictions may be imposed to prevent the user from
injecting malicious code.
in order to make algorithmic complexity attacks on (e.g.) web apps much more complicated.
The environment variable PYTHONHASHSEED and the new command line flag -R control this
behavior.
Inada Naoki
Victor Stinner
Jules Lasne (jlasne)
Xtreak
Serhiy Storchaka
Steve Dower
Victor Stinner
Stéphane Wirtel
Utkarsh Gupta
Cheryl Sabella
Xtreak
Carl Meyer
Nick Coghlan
Victor Stinner
Benjamin Peterson
Barry Warsaw
Berker Peksag
INADA Naoki
Xiang Zhang
Martin Panter
Steve Dower
Georg Brandl
Larry Hastings
Brett Cannon
R David Murray
Christian Heimes
Ezio Melotti
Antoine Pitrou
Andrew Svetlov
Éric Araujo