X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/d29303c9884e1ef715851d69acc5d54f84441720..0196437f8e062817d3277bb1484de3fbdcb3e19d:/README.md?ds=inline diff --git a/README.md b/README.md index 04905e2..3c63cb5 100644 --- a/README.md +++ b/README.md @@ -5,6 +5,7 @@

Build Status Actions Status +Actions Status Documentation Status Coverage Status License: MIT @@ -31,8 +32,9 @@ Try it out now using the [Black Playground](https://black.now.sh). Watch the --- _Contents:_ **[Installation and usage](#installation-and-usage)** | -**[Code style](#the-black-code-style)** | **[pyproject.toml](#pyprojecttoml)** | -**[Editor integration](#editor-integration)** | **[blackd](#blackd)** | +**[Code style](#the-black-code-style)** | **[Pragmatism](#pragmatism)** | +**[pyproject.toml](#pyprojecttoml)** | **[Editor integration](#editor-integration)** | +**[blackd](#blackd)** | **[black-primer](#black-primer)** | **[Version control integration](#version-control-integration)** | **[Ignoring unmodified files](#ignoring-unmodified-files)** | **[Used by](#used-by)** | **[Testimonials](#testimonials)** | **[Show your style](#show-your-style)** | @@ -52,7 +54,7 @@ run but you can reformat Python 2 code with it, too. To get started right away with sensible defaults: -``` +```sh black {source_file_or_directory} ``` @@ -61,36 +63,41 @@ black {source_file_or_directory} _Black_ doesn't provide many options. You can list them by running `black --help`: ```text -black [OPTIONS] [SRC]... +Usage: black [OPTIONS] [SRC]... + + The uncompromising code formatter. Options: -c, --code TEXT Format the code passed in as a string. -l, --line-length INTEGER How many characters per line to allow. [default: 88] + -t, --target-version [py27|py33|py34|py35|py36|py37|py38] Python versions that should be supported by Black's output. [default: per-file auto- detection] - --py36 Allow using Python 3.6-only syntax on all - input files. This will put trailing commas - in function signatures and calls also after - *args and **kwargs. Deprecated; use - --target-version instead. [default: per-file - auto-detection] + --pyi Format all input files like typing stubs regardless of file extension (useful when piping source on standard input). + -S, --skip-string-normalization Don't normalize string quotes or prefixes. --check Don't write the files back, just return the status. Return code 0 means nothing would change. Return code 1 means some files - would be reformatted. Return code 123 means + would be reformatted. Return code 123 means there was an internal error. + --diff Don't write the files back, just output a diff for each file on stdout. + + --color / --no-color Show colored diff. Only applies when + `--diff` is given. + --fast / --safe If --fast given, skip temporary sanity checks. [default: --safe] + --include TEXT A regular expression that matches files and directories that should be included on recursive searches. An empty value means @@ -99,6 +106,7 @@ Options: on all platforms (Windows, too). Exclusions are calculated first, inclusions later. [default: \.pyi?$] + --exclude TEXT A regular expression that matches files and directories that should be excluded on recursive searches. An empty value means no @@ -106,16 +114,23 @@ Options: directories on all platforms (Windows, too). Exclusions are calculated first, inclusions later. [default: /(\.eggs|\.git|\.hg|\.mypy - _cache|\.nox|\.tox|\.venv|_build|buck- + _cache|\.nox|\.tox|\.venv|\.svn|_build|buck- out|build|dist)/] + + --force-exclude TEXT Like --exclude, but files and directories + matching this regex will be excluded even + when they are passed explicitly as arguments + -q, --quiet Don't emit non-error messages to stderr. - Errors are still emitted, silence those with + Errors are still emitted; silence those with 2>/dev/null. + -v, --verbose Also emit messages to stderr about files that were not changed or were ignored due to --exclude=. + --version Show the version and exit. - --config PATH Read configuration from PATH. + --config FILE Read configuration from PATH. -h, --help Show this message and exit. ``` @@ -127,6 +142,60 @@ _Black_ is a well-behaved Unix-style command-line tool: - it only outputs messages to users on standard error; - exits with code 0 unless an internal error occurred (or `--check` was used). +### Using _Black_ with other tools + +While _Black_ enforces formatting that conforms to PEP 8, other tools may raise warnings +about _Black_'s changes or will overwrite _Black_'s changes. A good example of this is +[isort](https://pypi.org/p/isort). Since _Black_ is barely configurable, these tools +should be configured to neither warn about nor overwrite _Black_'s changes. + +Actual details on _Black_ compatible configurations for various tools can be found in +[compatible_configs](https://github.com/psf/black/blob/master/docs/compatible_configs.md). + +### Migrating your code style without ruining git blame + +A long-standing argument against moving to automated code formatters like _Black_ is +that the migration will clutter up the output of `git blame`. This was a valid argument, +but since Git version 2.23, Git natively supports +[ignoring revisions in blame](https://git-scm.com/docs/git-blame#Documentation/git-blame.txt---ignore-revltrevgt) +with the `--ignore-rev` option. You can also pass a file listing the revisions to ignore +using the `--ignore-revs-file` option. The changes made by the revision will be ignored +when assigning blame. Lines modified by an ignored revision will be blamed on the +previous revision that modified those lines. + +So when migrating your project's code style to _Black_, reformat everything and commit +the changes (preferably in one massive commit). Then put the full 40 characters commit +identifier(s) into a file. + +``` +# Migrate code style to Black +5b4ab991dede475d393e9d69ec388fd6bd949699 +``` + +Afterwards, you can pass that file to `git blame` and see clean and meaningful blame +information. + +```console +$ git blame important.py --ignore-revs-file .git-blame-ignore-revs +7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 1) def very_important_function(text, file): +abdfd8b0 (Alice Doe 2019-09-23 11:39:32 -0400 2) text = text.lstrip() +7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 3) with open(file, "r+") as f: +7a1ae265 (John Smith 2019-04-15 15:55:13 -0400 4) f.write(formatted) +``` + +You can even configure `git` to automatically ignore revisions listed in a file on every +call to `git blame`. + +```console +$ git config blame.ignoreRevsFile .git-blame-ignore-revs +``` + +**The one caveat is that GitHub and GitLab do not yet support ignoring revisions using +their native UI of blame.** So blame information will be cluttered with a reformatting +commit on those platforms. (If you'd like this feature, there's an open issue for +[GitLab](https://gitlab.com/gitlab-org/gitlab/-/issues/31423) and please let GitHub +know!) + ### NOTE: This is a beta product _Black_ is already [successfully used](#used-by) by many projects, small and big. It @@ -215,6 +284,69 @@ def very_important_function( ... ``` +_Black_ prefers parentheses over backslashes, and will remove backslashes if found. + +```py3 +# in: + +if some_short_rule1 \ + and some_short_rule2: + ... + +# out: + +if some_short_rule1 and some_short_rule2: + ... + + +# in: + +if some_long_rule1 \ + and some_long_rule2: + ... + +# out: + +if ( + some_long_rule1 + and some_long_rule2 +): + ... + +``` + +Backslashes and multiline strings are one of the two places in the Python grammar that +break significant indentation. You never need backslashes, they are used to force the +grammar to accept breaks that would otherwise be parse errors. That makes them confusing +to look at and brittle to modify. This is why _Black_ always gets rid of them. + +If you're reaching for backslashes, that's a clear signal that you can do better if you +slightly refactor your code. I hope some of the examples above show you that there are +many ways in which you can do it. + +However there is one exception: `with` statements using multiple context managers. +Python's grammar does not allow organizing parentheses around the series of context +managers. + +We don't want formatting like: + +```py3 +with make_context_manager1() as cm1, make_context_manager2() as cm2, make_context_manager3() as cm3, make_context_manager4() as cm4: + ... # nothing to split on - line too long +``` + +So _Black_ will now format it like this: + +```py3 +with \ + make_context_manager(1) as cm1, \ + make_context_manager(2) as cm2, \ + make_context_manager(3) as cm3, \ + make_context_manager(4) as cm4 \ +: + ... # backslashes and an ugly stranded colon +``` + You might have noticed that closing brackets are always dedented and that a trailing comma is always added. Such formatting produces smaller diffs; when you add or remove an element, it's always just one line. Also, having the closing bracket dedented provides a @@ -395,9 +527,12 @@ PEP 8 [recommends](https://www.python.org/dev/peps/pep-0008/#whitespace-in-expressions-and-statements) to treat `:` in slices as a binary operator with the lowest priority, and to leave an equal amount of space on either side, except if a parameter is omitted (e.g. -`ham[1 + 1 :]`). It also states that for extended slices, both `:` operators have to -have the same amount of spacing, except if a parameter is omitted (`ham[1 + 1 ::]`). -_Black_ enforces these rules consistently. +`ham[1 + 1 :]`). It recommends no spaces around `:` operators for "simple expressions" +(`ham[lower:upper]`), and extra space for "complex expressions" +(`ham[lower : upper + offset]`). _Black_ treats anything more than variable names as +"complex" (`ham[lower : upper + 1]`). It also states that for extended slices, both `:` +operators have to have the same amount of spacing, except if a parameter is omitted +(`ham[1 + 1 ::]`). _Black_ enforces these rules consistently. This behaviour may raise `E203 whitespace before ':'` warnings in style guide enforcement tools like Flake8. Since `E203` is not PEP 8 compliant, you should tell @@ -489,6 +624,47 @@ file that are not enforced yet but might be in a future version of the formatter - for arguments that default to `None`, use `Optional[]` explicitly; - use `float` instead of `Union[int, float]`. +## Pragmatism + +Early versions of _Black_ used to be absolutist in some respects. They took after its +initial author. This was fine at the time as it made the implementation simpler and +there were not many users anyway. Not many edge cases were reported. As a mature tool, +_Black_ does make some exceptions to rules it otherwise holds. This section documents +what those exceptions are and why this is the case. + +### The magic trailing comma + +_Black_ in general does not take existing formatting into account. + +However, there are cases where you put a short collection or function call in your code +but you anticipate it will grow in the future. + +For example: + +```py3 +TRANSLATIONS = { + "en_us": "English (US)", + "pl_pl": "polski", +} +``` + +Early versions of _Black_ used to ruthlessly collapse those into one line (it fits!). +Now, you can communicate that you don't want that by putting a trailing comma in the +collection yourself. When you do, _Black_ will know to always explode your collection +into one item per line. + +How do you make it stop? Just delete that trailing comma and _Black_ will collapse your +collection into one line if it fits. + +### r"strings" and R"strings" + +_Black_ normalizes string quotes as well as string prefixes, making them lowercase. One +exception to this rule is r-strings. It turns out that the very popular +[MagicPython](https://github.com/MagicStack/MagicPython/) syntax highlighter, used by +default by (among others) GitHub and Visual Studio Code, differentiates between +r-strings and R-strings. The former are syntax highlighted as regular expressions while +the latter are treated as true raw strings with no special semantics. + ## pyproject.toml _Black_ is able to read project-specific default values for its command line options @@ -580,8 +756,11 @@ file hierarchy. ### Emacs -Use [proofit404/blacken](https://github.com/proofit404/blacken) or -[Elpy](https://github.com/jorgenschaefer/elpy). +Options include the following: + +- [purcell/reformatter.el](https://github.com/purcell/reformatter.el) +- [proofit404/blacken](https://github.com/proofit404/blacken) +- [Elpy](https://github.com/jorgenschaefer/elpy). ### PyCharm/IntelliJ IDEA @@ -607,6 +786,9 @@ $ where black %LocalAppData%\Programs\Python\Python36-32\Scripts\black.exe # possible location ``` +Note that if you are using a virtual environment detected by PyCharm, this is an +unneeded step. In this case the path to `black` is `$PyInterpreterDirectory$/black`. + 3. Open External tools in PyCharm/IntelliJ IDEA On macOS: @@ -632,7 +814,7 @@ On Windows / Linux / BSD: 6. Optionally, run _Black_ on every file save: 1. Make sure you have the - [File Watcher](https://plugins.jetbrains.com/plugin/7177-file-watchers) plugin + [File Watchers](https://plugins.jetbrains.com/plugin/7177-file-watchers) plugin installed. 2. Go to `Preferences or Settings -> Tools -> File Watchers` and click `+` to add a new watcher: @@ -644,7 +826,7 @@ On Windows / Linux / BSD: - Output paths to refresh: `$FilePath$` - Working directory: `$ProjectFileDir$` - - Uncheck "Auto-save edited files to trigger the watcher" + - Uncheck "Auto-save edited files to trigger the watcher" in Advanced Options ### Wing IDE @@ -697,7 +879,7 @@ Configuration: To install with [vim-plug](https://github.com/junegunn/vim-plug): ``` -Plug 'psf/black' +Plug 'psf/black', { 'branch': 'stable' } ``` or with [Vundle](https://github.com/VundleVim/Vundle.vim): @@ -706,8 +888,15 @@ or with [Vundle](https://github.com/VundleVim/Vundle.vim): Plugin 'psf/black' ``` +and execute the following in a terminal: + +```console +$ cd ~/.vim/bundle/black +$ git checkout origin/stable -b stable +``` + or you can copy the plugin from -[plugin/black.vim](https://github.com/psf/black/tree/master/plugin/black.vim). +[plugin/black.vim](https://github.com/psf/black/blob/stable/plugin/black.vim). ``` mkdir -p ~/.vim/pack/python/start/black/plugin @@ -746,6 +935,55 @@ default. On macOS with Homebrew run: `brew install vim`. When building Vim from use: `./configure --enable-python3interp=yes`. There's many guides online how to do this. +**I get an import error when using _Black_ from a virtual environment**: If you get an +error message like this: + +```text +Traceback (most recent call last): + File "", line 63, in + File "/home/gui/.vim/black/lib/python3.7/site-packages/black.py", line 45, in + from typed_ast import ast3, ast27 + File "/home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/ast3.py", line 40, in + from typed_ast import _ast3 +ImportError: /home/gui/.vim/black/lib/python3.7/site-packages/typed_ast/_ast3.cpython-37m-x86_64-linux-gnu.so: undefined symbool: PyExc_KeyboardInterrupt +``` + +Then you need to install `typed_ast` and `regex` directly from the source code. The +error happens because `pip` will download [Python wheels](https://pythonwheels.com/) if +they are available. Python wheels are a new standard of distributing Python packages and +packages that have Cython and extensions written in C are already compiled, so the +installation is much more faster. The problem here is that somehow the Python +environment inside Vim does not match with those already compiled C extensions and these +kind of errors are the result. Luckily there is an easy fix: installing the packages +from the source code. + +The two packages that cause the problem are: + +- [regex](https://pypi.org/project/regex/) +- [typed-ast](https://pypi.org/project/typed-ast/) + +Now remove those two packages: + +```console +$ pip uninstall regex typed-ast -y +``` + +And now you can install them with: + +```console +$ pip install --no-binary :all: regex typed-ast +``` + +The C extensions will be compiled and now Vim's Python environment will match. Note that +you need to have the GCC compiler and the Python development files installed (on +Ubuntu/Debian do `sudo apt-get install build-essential python3-dev`). + +If you later want to update _Black_, you should do it like this: + +```console +$ pip install -U black --no-binary regex,typed-ast +``` + ### Visual Studio Code Use the @@ -773,7 +1011,7 @@ Use [python-black](https://atom.io/packages/python-black). ### Kakoune -Add the following hook to your kakrc, then run black with `:format`. +Add the following hook to your kakrc, then run _Black_ with `:format`. ``` hook global WinSetOption filetype=python %{ @@ -832,7 +1070,7 @@ Options: There is no official blackd client tool (yet!). You can test that blackd is working using `curl`: -``` +```sh blackd --bind-port 9090 & # or let blackd choose a port curl -s -XPOST "localhost:9090" -d "print('valid')" ``` @@ -881,6 +1119,124 @@ Apart from the above, `blackd` can produce the following response codes: The response headers include a `X-Black-Version` header containing the version of _Black_. +## black-primer + +`black-primer` is a tool built for CI (and huumans) to have _Black_ `--check` a number +of (configured in `primer.json`) Git accessible projects in parallel. _(A PR will be +accepted to add Mercurial support.)_ + +### Run flow + +- Ensure we have a `black` + `git` in PATH +- Load projects from `primer.json` +- Run projects in parallel with `--worker` workers (defaults to CPU count / 2) + - Checkout projects + - Run black and record result + - Clean up repository checkout _(can optionally be disabled via `--keep`)_ +- Display results summary to screen +- Default to cleaning up `--work-dir` (which defaults to tempfile schemantics) +- Return + - 0 for successful run + - < 0 for environment / internal error + - > 0 for each project with an error + +### Speed up Runs 🏎 + +If you're running locally yourself to test black on lots of code try: + +- Using `-k` / `--keep` + `-w` / `--work-dir` so you don't have to re-checkout the repo + each run + +### CLI Arguments + +```text +Usage: black-primer [OPTIONS] + + primer - prime projects for blackening... 🏴 + +Options: + -c, --config PATH JSON config file path [default: /Users/cooper/repos/ + black/src/black_primer/primer.json] + + --debug Turn on debug logging [default: False] + -k, --keep Keep workdir + repos post run [default: False] + -L, --long-checkouts Pull big projects to test [default: False] + -R, --rebase Rebase project if already checked out [default: + False] + + -w, --workdir PATH Directory Path for repo checkouts [default: /var/fol + ders/tc/hbwxh76j1hn6gqjd2n2sjn4j9k1glp/T/primer.20200 + 517125229] + + -W, --workers INTEGER Number of parallel worker coroutines [default: 69] + -h, --help Show this message and exit. +``` + +### primer config file + +The config is JSON format. Its main element is the `"projects"` dictionary. Below +explains each parameter: + +```json +{ + "projects": { + "00_Example": { + "cli_arguments": "List of extra CLI arguments to pass Black for this project", + "expect_formatting_changes": "Boolean to indicate that the version of Black is expected to cause changes", + "git_clone_url": "URL you would pass `git clone` to check out this repo", + "long_checkout": "Boolean to have repo skipped by defauult unless `--long-checkouts` is specified", + "py_versions": "List of major Python versions to run this project with - all will do as you'd expect - run on ALL versions" + }, + "aioexabgp": { + "cli_arguments": [], + "expect_formatting_changes": true, + "git_clone_url": "https://github.com/cooperlees/aioexabgp.git", + "long_checkout": false, + "py_versions": ["all", "3.8"] // "all" ignores all other versions + } + } +} +``` + +### Example run + +```console +cooper-mbp:black cooper$ ~/venvs/b/bin/black-primer +[2020-05-17 13:06:40,830] INFO: 4 projects to run Black over (lib.py:270) +[2020-05-17 13:06:44,215] INFO: Analyzing results (lib.py:285) +-- primer results 📊 -- + +3 / 4 succeeded (75.0%) ✅ +1 / 4 FAILED (25.0%) 💩 + - 0 projects disabled by config + - 0 projects skipped due to Python version + - 0 skipped due to long checkout + +Failed projects: + +### flake8-bugbear: + - Returned 1 + - stdout: +--- tests/b303_b304.py 2020-05-17 20:04:09.991227 +0000 ++++ tests/b303_b304.py 2020-05-17 20:06:42.753851 +0000 +@@ -26,11 +26,11 @@ + maxint = 5 # this is okay + # the following shouldn't crash + (a, b, c) = list(range(3)) + # it's different than this + a, b, c = list(range(3)) +- a, b, c, = list(range(3)) ++ a, b, c = list(range(3)) + # and different than this + (a, b), c = list(range(3)) + a, *b, c = [1, 2, 3, 4, 5] + b[1:3] = [0, 0] + +would reformat tests/b303_b304.py +Oh no! 💥 💔 💥 +1 file would be reformatted, 22 files would be left unchanged. +``` + ## Version control integration Use [pre-commit](https://pre-commit.com/). Once you @@ -905,7 +1261,7 @@ for your project. See _Black_'s own example. If you're already using Python 3.7, switch the `language_version` accordingly. Finally, -`stable` is a tag that is pinned to the latest release on PyPI. If you'd rather run on +`stable` is a branch that tracks the latest release on PyPI. If you'd rather run on master, this is also an option. ## Ignoring unmodified files @@ -934,8 +1290,10 @@ then write the above files to `.cache/black//`. The following notable open-source projects trust _Black_ with enforcing a consistent code style: pytest, tox, Pyramid, Django Channels, Hypothesis, attrs, SQLAlchemy, -Poetry, PyPA applications (Warehouse, Pipenv, virtualenv), pandas, Pillow, every Datadog -Agent Integration, Home Assistant. +Poetry, PyPA applications (Warehouse, Bandersnatch, Pipenv, virtualenv), pandas, Pillow, +every Datadog Agent Integration, Home Assistant. + +The following organizations use _Black_: Facebook, Dropbox. Are we missing anyone? Let us know. @@ -994,7 +1352,14 @@ other hand, if your answer is "because I don't like a particular formatting" the not ready to embrace _Black_ yet. Such changes are unlikely to get accepted. You can still try but prepare to be disappointed. -More details can be found in [CONTRIBUTING](CONTRIBUTING.md). +More details can be found in +[CONTRIBUTING](https://github.com/psf/black/blob/master/CONTRIBUTING.md). + +## Change Log + +The log's become rather long. It moved to its own file. + +See [CHANGES](https://github.com/psf/black/blob/master/CHANGES.md). ## Authors @@ -1003,12 +1368,13 @@ Glued together by [Łukasz Langa](mailto:lukasz@langa.pl). Maintained with [Carol Willing](mailto:carolcode@willingconsulting.com), [Carl Meyer](mailto:carl@oddbird.net), [Jelle Zijlstra](mailto:jelle.zijlstra@gmail.com), -[Mika Naylor](mailto:mail@autophagy.io), and -[Zsolt Dollenstein](mailto:zsol.zsol@gmail.com). +[Mika Naylor](mailto:mail@autophagy.io), +[Zsolt Dollenstein](mailto:zsol.zsol@gmail.com), and +[Cooper Lees](mailto:me@cooperlees.com). Multiple contributions by: -- [Abdur-Rahmaan Janhangeer](mailto:cryptolabour@gmail.com) +- [Abdur-Rahmaan Janhangeer](mailto:arj.python@gmail.com) - [Adam Johnson](mailto:me@adamj.eu) - [Alexander Huynh](mailto:github@grande.coffee) - [Andrew Thorp](mailto:andrew.thorp.dev@gmail.com)