"Zero cost" exception handling.
* Uses a lookup table to determine how to handle exceptions.
* Removes SETUP_FINALLY and POP_TOP block instructions, eliminating (most of) the runtime overhead of try statements.
* Reduces the size of the frame object by about 60%.
To improve the user experience understanding what part of the error messages associated with SyntaxErrors is wrong, we can highlight the whole error range and not only place the caret at the first character. In this way:
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^
SyntaxError: Generator expression must be parenthesized
becomes
>>> foo(x, z for z in range(10), t, w)
File "<stdin>", line 1
foo(x, z for z in range(10), t, w)
^^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
When printing NameError raised by the interpreter, PyErr_Display
will offer suggestions of simmilar variable names in the function that the exception
was raised from:
>>> schwarzschild_black_hole = None
>>> schwarschild_black_hole
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?
When printing AttributeError, PyErr_Display will offer suggestions of similar
attribute names in the object that the exception was raised from:
>>> collections.namedtoplo
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: namedtuple?
When trying to extract the error line for the error message there
are two distinct cases:
1. The input comes from a file, which means that we can extract the
error line by using `PyErr_ProgramTextObject` and which we already
do.
2. The input does not come from a file, at which point we need to get
the source code from the tokenizer:
* If the tokenizer's current line number is the same with the line
of the error, we get the line from `tok->buf` and we're ready.
* Else, we can extract the error line from the source code in the
following two ways:
* If the input comes from a string we have all the input
in `tok->str` and we can extract the error line from it.
* If the input comes from stdin, i.e. the interactive prompt, we
do not have access to the previous line. That's why a new
field `tok->stdin_content` is added which holds the whole input for the
current (multiline) statement or expression. We can then extract the
error line from `tok->stdin_content` like we do in the string case above.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
When allocating MemoryError classes, there is some logic to use
pre-allocated instances in a freelist only if the type that is being
allocated is not a subclass of MemoryError. Unfortunately in the
destructor this logic is not present so the freelist is altered even
with subclasses of MemoryError.
The following error messages get produced:
- `cannot delete ...` for invalid `del` targets
- `... is an illegal 'for' target` for invalid targets in for
statements
- `... is an illegal 'with' target` for invalid targets in
with statements
Additionally, a few `cut`s were added in various places before the
invocation of the `invalid_*` rule, in order to speed things
up.
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
This commit removes the old parser, the deprecated parser module, the old parser compatibility flags and environment variables and all associated support code and documentation.
This commit fixes SyntaxError locations when the caret is not displayed,
by doing the following:
- `col_number` always gets set to the location of the offending
node/expr. When no caret is to be displayed, this gets achieved
by setting the object holding the error line to None.
- Introduce a new function `_PyPegen_raise_error_known_location`,
which can be called, when an arbitrary `lineno`/`col_offset`
needs to be passed. This function then gets used in the grammar
(through some new macros and inline functions) so that SyntaxError
locations of the new parser match that of the old.
When parsing something like `f(g()=2)`, where the name of a default arg
is not a NAME, but an arbitrary expression, a specialised error message
is emitted.
When parsing things like `def f(*): pass` the old parser used to output `SyntaxError: named arguments must follow bare *`, which the new parser wasn't able to do.
* Rename PyConfig.use_peg to _use_peg_parser
* Document PyConfig._use_peg_parser and mark it a deprecated
* Mark -X oldparser option and PYTHONOLDPARSER env var as deprecated
in the documentation.
* Add use_old_parser() and skip_if_new_parser() to test.support
* Remove sys.flags.use_peg: use_old_parser() uses
_testinternalcapi.get_configs() instead.
* Enhance test_embed tests
* subprocess._args_from_interpreter_flags() copies -X oldparser
The Py_FatalError() function is replaced with a macro which logs
automatically the name of the current function, unless the
Py_LIMITED_API macro is defined.
Changes:
* Add _Py_FatalErrorFunc() function.
* Remove the function name from the message of Py_FatalError() calls
which included the function name.
* Update tests.
* Copy test_exceptions.test_unraisable() to
test_sys.UnraisableHookTest().
* Use catch_unraisable_exception() in test_coroutines,
test_exceptions, test_generators.
The lineno and col_offset attributes of AST nodes for list comprehensions,
generator expressions and tuples are now point to the opening parenthesis or
square brace. For tuples without parenthesis they point to the position
of the first item.
