Fixes and improvements to `int.to_bytes()` are:
- No longer overflows if byte size is 0 (closes#13041).
- Raises OverflowError in any case where number won't fit into byte length
(now matches CPython, previously MicroPython would return a truncated
bytes object).
- Document that `micropython int.to_bytes()` doesn't implement the optional
signed kwarg, but will behave as if `signed=True` when the integer is
negative (this is the current behaviour). Add tests for this also.
Requires changes for small ints, MPZ large ints, and "long long" large
ints.
Adds a new set of unit tests for ints between 32 and 64 bits to increase
coverage of "long long" large ints, which are otherwise untested.
Tested on unix port (64 bit small ints, MPZ long ints) and Zephyr STM32WB
board (32 bit small ints, long long large ints).
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
This commit adds the errno attribute to exceptions, so code can retrieve
errno codes from an OSError using exc.errno.
The implementation here simply lets `errno` (and the existing `value`)
attributes work on any exception instance (they both alias args[0]). This
is for efficiency and to keep code size down. The pros and cons of this
are:
Pros:
- more compatible with CPython, less difference to document and learn
- OSError().errno will correctly return None, whereas the current way of
doing it via OSError().args[0] will raise an IndexError
- it reduces code size on most bare-metal ports (because they already have
the errno qstr)
- for Python code that uses exc.errno the generated bytecode is 2 bytes
smaller and more efficient to execute (compared with exc.args[0]); so
bytecode loaded to RAM saves 2 bytes RAM for each use of this attribute,
and bytecode that is frozen saves 2 bytes flash/ROM for each use
- it's easier/shorter to type, and saves 2 bytes of space in .py files that
use it (for each use)
Cons:
- increases code size by 4-8 bytes on minimal ports that don't already have
the `errno` qstr
- all exceptions now have .errno and .value attributes (a cpydiff test is
added to address this)
See also #2407.
Signed-off-by: Damien George <damien@micropython.org>
