Bad f-string, causing CI issues

@coolreader18

Feature

Toy Example (adapted from `extra_tests/snippets/fstrings.py`, lines 47-48)

Code

foo = "bar"
part_spec = ">+#10x"
print(f"{16:0{part_spec}}{foo}")

CPython

00000+0x10bar

RustPython

SyntaxError: Got error in f-string: Invalid expression: invalid syntax. Got unexpected token 'part_spec' at line 1 column 9
print(f"{16:0{part_spec}}{foo}")
        ^

Real-world Example (adapted from CPython 3.9's `Lib/test/test_fstring.py`, lines 581-584)

Code

import decimal
width = 10
precision = 4
value = decimal.Decimal('12.34567')
print(f'result: {value:{width}.{precision}}')

CPython

result:      12.35

RustPython

SyntaxError: Got error in f-string: Invalid expression: invalid syntax. Got unexpected token '{' at line 1 column 9
print(f'result: {value:{width}.{precision}}')
        ^

Python Documentation

https://docs.python.org/3/reference/lexical_analysis.html#grammar-token-python-grammar-format_spec

@coolreader18 this has been plaguing the CI for the past day or so (because of the --install-pip step).

@coolreader18

@coolreader18 Update: I had an insight related to something in ast/src/ast_gen.rs, and I'm working on a thing.

@fanninpm

I just tried rustpython get-pip.py on latest HEAD (bd295e0) and it threw

 File "/Users/Shared/projects/RustPython/vm/pylib-crate/Lib/zipimport.py", line 191, in get_filename
    code, ispackage, modpath = _get_module_code(self, fullname)
  File "/Users/Shared/projects/RustPython/vm/pylib-crate/Lib/zipimport.py", line 713, in _get_module_code
    code = _compile_source(modpath, data)
  File "/Users/Shared/projects/RustPython/vm/pylib-crate/Lib/zipimport.py", line 647, in _compile_source
    return compile(source, pathname, 'exec', dont_inherit=True)
SyntaxError: Got error in f-string: Invalid expression: invalid syntax. Got unexpected token ',' at line 408 column 27
        completed_str = f"{completed_ratio:,.{precision}f}"
                          ^

Extracted example:

On CPython 3.9.9:

>>> completed_ratio = 1212.121212
>>> precision = 2
>>> f"{completed_ratio:,.{precision}f}"
'1,212.12'

On Rust Python 0.1.2:

>>>>> completed_ratio = 1212.121212
>>>>> precision = 2
>>>>> f"{completed_ratio:,.{precision}f}"
SyntaxError: Got error in f-string: Invalid expression: invalid syntax. Got unexpected token ',' at line 1 column 3
f"{completed_ratio:,.{precision}f}"
  ^

@fanninpm Does your PR fix this too?

@fanninpm

@fanninpm Does your PR fix this too?

Not completely.

Once this is fixed, #3535 need to be reverted

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Bad f-string, causing CI issues #3531

Feature

Toy Example (adapted from `extra_tests/snippets/fstrings.py`, lines 47-48)

Code

CPython

RustPython

Real-world Example (adapted from CPython 3.9's `Lib/test/test_fstring.py`, lines 581-584)

Code

CPython

RustPython

Python Documentation

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Bad f-string, causing CI issues #3531

Description

Feature

Toy Example (adapted from extra_tests/snippets/fstrings.py, lines 47-48)

Code

CPython

RustPython

Real-world Example (adapted from CPython 3.9's Lib/test/test_fstring.py, lines 581-584)

Code

CPython

RustPython

Python Documentation

Activity

fanninpm commented on Feb 1, 2022

gavindsouza commented on Feb 3, 2022

fanninpm commented on Feb 3, 2022

youknowone commented on Feb 3, 2022

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Issue actions

Toy Example (adapted from `extra_tests/snippets/fstrings.py`, lines 47-48)

Real-world Example (adapted from CPython 3.9's `Lib/test/test_fstring.py`, lines 581-584)