X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/04518c38c945ecf3c15765b71642112495cade8d..05e1fbf27d93df36b09c560791ad46c6ce3eb518:/docs/faq.md?ds=inline diff --git a/docs/faq.md b/docs/faq.md index 46e4598..0a966c9 100644 --- a/docs/faq.md +++ b/docs/faq.md @@ -21,7 +21,8 @@ _Black_ is still in [beta](index.rst), some edges are still a bit rough. To comb issues, the equivalence of code after formatting is [checked](the_black_code_style/current_style.md#ast-before-and-after-formatting) with limited special cases where the code is allowed to differ. If issues are found, an error -is raised and the file is left untouched. +is raised and the file is left untouched. Magical comments that influence linters and +other tools, such as `# noqa`, may be moved by _Black_. See below for more details. ## How stable is Black's style? @@ -30,12 +31,40 @@ pragmatism. However, _Black_ is still in beta so style changes are both planned still proposed on the issue tracker. See [The Black Code Style](the_black_code_style/index.rst) for more details. +Starting in 2022, the formatting output will be stable for the releases made in the same +year (other than unintentional bugs). It is possible to opt-in to the latest formatting +styles, using the `--future` flag. + ## Why is my file not formatted? Most likely because it is ignored in `.gitignore` or excluded with configuration. See [file collection and discovery](usage_and_configuration/file_collection_and_discovery.md) for details. +## Why is my Jupyter Notebook cell not formatted? + +_Black_ is timid about formatting Jupyter Notebooks. Cells containing any of the +following will not be formatted: + +- automagics (e.g. `pip install black`) +- non-Python cell magics (e.g. `%%writeline`) +- multiline magics, e.g.: + + ```python + %timeit f(1, \ + 2, \ + 3) + ``` + +- code which `IPython`'s `TransformerManager` would transform magics into, e.g.: + + ```python + get_ipython().system('ls') + ``` + +- invalid syntax, as it can't be safely distinguished from automagics in the absence of + a running `IPython` kernel. + ## Why are Flake8's E203 and W503 violated? Because they go against PEP 8. E203 falsely triggers on list @@ -46,7 +75,33 @@ disabled-by-default counterpart W504. E203 should be disabled while changes are ## Does Black support Python 2? +```{warning} +Python 2 support has been deprecated since 21.10b0. + +This support will be dropped in the first stable release, expected for January 2022. +See [The Black Code Style](the_black_code_style/index.rst) for details. +``` + For formatting, yes! [Install](getting_started.md#installation) with the `python2` extra -to format Python 2 files too! There are no current plans to drop support, but most -likely it is bound to happen. Sometime. Eventually. In terms of running _Black_ though, -Python 3.6 or newer is required. +to format Python 2 files too! In terms of running _Black_ though, Python 3.6 or newer is +required. + +## Why does my linter or typechecker complain after I format my code? + +Some linters and other tools use magical comments (e.g., `# noqa`, `# type: ignore`) to +influence their behavior. While Black does its best to recognize such comments and leave +them in the right place, this detection is not and cannot be perfect. Therefore, you'll +sometimes have to manually move these comments to the right place after you format your +codebase with _Black_. + +## Can I run Black with PyPy? + +Yes, there is support for PyPy 3.7 and higher. You cannot format Python 2 files under +PyPy, because PyPy's inbuilt ast module does not support this. + +## Why does Black not detect syntax errors in my code? + +_Black_ is an autoformatter, not a Python linter or interpreter. Detecting all syntax +errors is not a goal. It can format all code accepted by CPython (if you find an example +where that doesn't hold, please report a bug!), but it may also format some code that +CPython doesn't accept.