Five related CPython parity gaps in `str` formatting and construction:
1. **`str(bytes, errors=...)` triggers decode mode.** Previously, only
`encoding=` triggered decode; passing only `errors=` fell back to
`repr()`. CPython's behavior: presence of `encoding` OR `errors`
triggers decode mode (default UTF-8 when only `errors` is given).
2. **`'{...}'.format() IndexError wording.** Generic Rust "tuple index
out of range" replaced with CPython's "Replacement index N out of
range for positional args tuple".
3. **`{0:3.2s}.format('abc')` → 'ab '.** String format spec applied
precision after width padding; CPython truncates BEFORE padding.
Reorder the operations.
4. **`%x` / `%o` / `%X` / `%c` accept `__index__` objects.** Previously
only `PyInt` downcast was attempted. Mirror CPython's
PyNumber_Index dispatch via `try_index_opt`.
5. **`%d` / `%u` / `%i` error wording.** "a number is required" →
"a real number is required" (matches CPython).
Also adds `not <type>` suffix to `%c` error messages so the type is
visible in TypeError text (matches CPython structure even without
fully-qualified names).
Verified byte-identical with CPython 3.14.4 across 25+ probes covering
the format/spec/constructor combinations. Unmasks
`test_str.test_constructor_keyword_args` and
`test_str.test_constructor_defaults`. test_str/test_bytes/test_format/
test_codecs/test_io/test_unicode_identifiers — 1,429 tests pass, 0
regressions. All 188 `extra_tests/snippets/*.py` pass under the CI
feature set.
`test_str.test_format` and `test_str.test_formatting` markers retained:
`test_format` still trips on `'{0:08s}'.format('result')` (numeric
zero-pad treated as fill+left-align by CPython for str type — separate
format-spec parser concern). `test_formatting` still trips on
`%c` error message expecting fully qualified `module.qualname` (RP
returns bare class name — separate broader concern).
This directory contains all of the Python files that make up the standard
library for RustPython.
Most of these files are copied over from the CPython repository (the 3.7
branch), with slight modifications to allow them to work under RustPython. The
current goal is to complete the standard library with as few modifications as
possible. Current modifications are just temporary workarounds for bugs/missing
feature within the RustPython implementation.
The first big module we are targeting is unittest, so we can leverage the
CPython test suite.
Changjoon
156942e37f