Max line length with bugbear (#3731)

[etc/vim.git] / docs / the_black_code_style / current_style.md

diff --git a/docs/the_black_code_style/current_style.md b/docs/the_black_code_style/current_style.md
index 56b92529d7055776bf830984d61ae58e9f40fb45..0fb59fe5aaed953d4472cea271cbf8882a50a34f 100644 (file)
--- a/docs/the_black_code_style/current_style.md
+++ b/docs/the_black_code_style/current_style.md
@@ -140,6 +140,8 @@ If you're reaching for backslashes, that's a clear signal that you can do better
 slightly refactor your code. I hope some of the examples above show you that there are
 many ways in which you can do it.
 
+(labels/line-length)=
+
 ### Line length
 
 You probably noticed the peculiar default line length. _Black_ defaults to 88 characters
@@ -158,33 +160,35 @@ harder to work with line lengths exceeding 100 characters. It also adversely aff
 side-by-side diff review on typical screen resolutions. Long lines also make it harder
 to present code neatly in documentation or talk slides.
 
-If you're using Flake8, you can bump `max-line-length` to 88 and mostly forget about it.
-However, it's better if you use [Bugbear](https://github.com/PyCQA/flake8-bugbear)'s
-B950 warning instead of E501, and bump the max line length to 88 (or the `--line-length`
-you used for black), which will align more with black's _"try to respect
-`--line-length`, but don't become crazy if you can't"_. You'd do it like this:
-
-```ini
-[flake8]
-max-line-length = 88
-...
-select = C,E,F,W,B,B950
-extend-ignore = E203, E501
-```
+#### Flake8
 
-Explanation of why E203 is disabled can be found further in this documentation. And if
-you're curious about the reasoning behind B950,
-[Bugbear's documentation](https://github.com/PyCQA/flake8-bugbear#opinionated-warnings)
-explains it. The tl;dr is "it's like highway speed limits, we won't bother you if you
-overdo it by a few km/h".
+If you use Flake8, you have a few options:
 
-**If you're looking for a minimal, black-compatible flake8 configuration:**
+1. Recommended is using [Bugbear](https://github.com/PyCQA/flake8-bugbear) and enabling
+   its B950 check instead of using Flake8's E501, because it aligns with Black's 10%
+   rule. Install Bugbear and use the following config:
 
-```ini
-[flake8]
-max-line-length = 88
-extend-ignore = E203
-```
+   ```ini
+   [flake8]
+   max-line-length = 80
+   ...
+   select = C,E,F,W,B,B950
+   extend-ignore = E203, E501
+   ```
+
+   The rationale for E950 is explained in
+   [Bugbear's documentation](https://github.com/PyCQA/flake8-bugbear#opinionated-warnings).
+
+2. For a minimally compatible config:
+
+   ```ini
+   [flake8]
+   max-line-length = 88
+   extend-ignore = E203
+   ```
+
+An explanation of why E203 is disabled can be found in the [Slices section](#slices) of
+this page.
 
 ### Empty lines
 
@@ -194,7 +198,45 @@ that in-function vertical whitespace should only be used sparingly.
 _Black_ will allow single empty lines inside functions, and single and double empty
 lines on module level left by the original editors, except when they're within
 parenthesized expressions. Since such expressions are always reformatted to fit minimal
-space, this whitespace is lost.
+space, this whitespace is lost. The other exception is that it will remove any empty
+lines immediately following a statement that introduces a new indentation level.
+
+```python
+# in:
+
+def foo():
+
+    print("All the newlines above me should be deleted!")
+
+
+if condition:
+
+    print("No newline above me!")
+
+    print("There is a newline above me, and that's OK!")
+
+
+class Point:
+
+    x: int
+    y: int
+
+# out:
+
+def foo():
+    print("All the newlines above me should be deleted!")
+
+
+if condition:
+    print("No newline above me!")
+
+    print("There is a newline above me, and that's OK!")
+
+
+class Point:
+    x: int
+    y: int
+```
 
 It will also insert proper spacing before and after function definitions. It's one line
 before and after inner functions and two lines before and after module-level functions
@@ -235,6 +277,8 @@ A pre-existing trailing comma informs _Black_ to always explode contents of the
 bracket pair into one item per line. Read more about this in the
 [Pragmatism](#pragmatism) section below.
 
+(labels/strings)=
+
 ### Strings
 
 _Black_ prefers double quotes (`"` and `"""`) over single quotes (`'` and `'''`). It
@@ -419,6 +463,8 @@ there were not many users anyway. Not many edge cases were reported. As a mature
 _Black_ does make some exceptions to rules it otherwise holds. This section documents
 what those exceptions are and why this is the case.
 
+(labels/magic-trailing-comma)=
+
 ### The magic trailing comma
 
 _Black_ in general does not take existing formatting into account.
@@ -455,6 +501,8 @@ 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.
 
+(labels/ast-changes)=
+
 ### AST before and after formatting
 
 When run with `--safe` (the default), _Black_ checks that the code before and after is