Prior to this commit, importing a module that exists but has a syntax error
or some other problem that happens at import time would result in a
potentially-incomplete module object getting added to sys.modules.
Subsequent imports would use that object, resulting in confusing error
messages that hide the root cause of the problem.
This commit fixes that issue by removing the failed module from sys.modules
using the new NLR callback mechanism.
Note that it is still important to add the module to sys.modules while the
import is happening so that we can support circular imports just like
CPython does.
Fixes issue #967.
Signed-off-by: David Grayson <davidegrayson@gmail.com>
When foo.bar is imported, bar is added as an attribute to foo. Previously
this happened on every import, but should only happen on first import.
This verifies the behavior for relative imports and overriding.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This verifies the behavior:
- Exact matches of built-ins bypass filesystem.
- u-prefix modules can be overridden from the filesystem.
- Builtin import can be forced using either u-prefix or sys.path=[].
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This matches class `__dict__`, and is similarly gated on
MICROPY_CPYTHON_COMPAT. Unlike class though, because modules's globals are
actually dict instances, the result is a mutable dictionary.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
These tests are specific to MicroPython so have a better home in the
micropython/ test subdir, and putting them here allows them to be run by
all targets, not just those that have access to the local filesystem (eg
the unix port).
Signed-off-by: Damien George <damien@micropython.org>
This adds the Python files in the tests/ directory to be formatted with
./tools/codeformat.py. The basics/ subdirectory is excluded for now so we
aren't changing too much at once.
In a few places `# fmt: off`/`# fmt: on` was used where the code had
special formatting for readability or where the test was actually testing
the specific formatting.
Because CPython 3.8.0 now produces different output:
- basics/parser.py: CPython does not allow '\\\n' as input.
- import/import_override: CPython imports _io.
Instead of encoding 4 zero bytes as placeholders for the simple_name and
source_file qstrs, and storing the qstrs after the bytecode, store the
qstrs at the location of these 4 bytes. This saves 4 bytes per bytecode
function stored in a .mpy file (for example lcd160cr.mpy drops by 232
bytes, 4x 58 functions). And resulting code size is slightly reduced on
ports that use this feature.
This check follows CPython's behaviour, because 'import *' always populates
the globals with the imported names, not locals.
Since it's safe to do this (doesn't lead to a crash or undefined behaviour)
the check is only enabled for MICROPY_CPYTHON_COMPAT.
Fixes issue #5121.
This patch compresses the second part of the bytecode prelude which
contains the source file name, function name, source-line-number mapping
and cell closure information. This part of the prelude now begins with a
single varible length unsigned integer which encodes 2 numbers, being the
byte-size of the following 2 sections in the header: the "source info
section" and the "closure section". After decoding this variable unsigned
integer it's possible to skip over one or both of these sections very
easily.
This scheme saves about 2 bytes for most functions compared to the original
format: one in the case that there are no closure cells, and one because
padding was eliminated.
The start of the bytecode prelude contains 6 numbers telling the amount of
stack needed for the Python values and exceptions, and the signature of the
function. Prior to this patch these numbers were all encoded one after the
other (2x variable unsigned integers, then 4x bytes), but using so many
bytes is unnecessary.
An entropy analysis of around 150,000 bytecode functions from the CPython
standard library showed that the optimal Shannon coding would need about
7.1 bits on average to encode these 6 numbers, compared to the existing 48
bits.
This patch attempts to get close to this optimal value by packing the 6
numbers into a single, varible-length unsigned integer via bit-wise
interleaving. The interleaving scheme is chosen to minimise the average
number of bytes needed, and at the same time keep the scheme simple enough
so it can be implemented without too much overhead in code size or speed.
The scheme requires about 10.5 bits on average to store the 6 numbers.
As a result most functions which originally took 6 bytes to encode these 6
numbers now need only 1 byte (in 80% of cases).
This is an implementation of a sliding qstr window used to reduce the
number of qstrs stored in a .mpy file. The window size is configured to 32
entries which takes a fixed 64 bytes (16-bits each) on the C stack when
loading/saving a .mpy file. It allows to remember the most recent 32 qstrs
so they don't need to be stored again in the .mpy file. The qstr window
uses a simple least-recently-used mechanism to discard the least recently
used qstr when the window overflows (similar to dictionary compression).
This scheme only needs a single pass to save/load the .mpy file.
Reduces mpy file size by about 25% with a window size of 32.
Configurable via MICROPY_MODULE_GETATTR, disabled by default. Among other
things __getattr__ for modules can help to build lazy loading / code
unloading at runtime.
Tests in basics (which should probably be renamed to core) should not
rely on float, or import any non-built-in files. This way these tests
can be run when those features are not available.
All test in basics now pass on the pyboard using stmhal port, except for
string-repr which has some issues with character hex printing.
