update flake8 config + add to CI code checks

Author: jorisvandenbossche

ci/code_checks.sh

@@ -52,6 +52,13 @@ fi
 ### LINTING ###
 if [[ -z "$CHECK" || "$CHECK" == "lint" ]]; then
 
+    echo "black --version"
+    black --version
+
+    MSG='Checking black formatting' ; echo $MSG
+    black pandas --check
+    RET=$(($RET + $?)) ; echo $MSG "DONE"
+
     # `setup.cfg` contains the list of error codes that are being ignored in flake8
 
     echo "flake8 --version"

environment.yml

@@ -16,6 +16,7 @@ dependencies:
   - cython>=0.28.2
 
   # code checks
+  - black
   - cpplint
   - flake8
   - flake8-comprehensions  # used by flake8, linting of unnecessary comprehensions

setup.cfg

@@ -12,8 +12,11 @@ tag_prefix = v
 parentdir_prefix = pandas-
 
 [flake8]
-max-line-length = 79
+max-line-length = 88
 ignore =
+    E501,  # longer line length
+    E203,  # space before : (needed for how black formats slicing)
+    E231,  # space after comma (needed for how black formats getitem with final comma)
     W503,  # line break before binary operator
     W504,  # line break after binary operator
     E402,  # module level import not at top of file