Add Black and other auto formatters as pre-commit hooks

.circleci/config.yml.in

@@ -92,6 +92,25 @@ jobs:
             python .circleci/regenerate.py
             git diff --exit-code || (echo ".circleci/config.yml not in sync with config.yml.in! Run .circleci/regenerate.py to update config"; exit 1)
 
+  lint_python_and_config:
+    docker:
+      - image: circleci/python:3.7
+    steps:
+      - checkout
+      - run:
+          name: Install pre-commit
+          command: pip install --user --progress-bar off pre-commit
+      - run:
+          name: Install pre-commit hooks
+          command: pre-commit install-hooks
+      - run:
+          name: Lint Python code and config files
+          command: pre-commit run --all-files
+      - run:
+          name: Required lint modifications
+          when: always
+          command: git --no-pager diff --color=always
+
   binary_linux_wheel:
     <<: *binary_common
     docker:
@@ -610,6 +629,9 @@ jobs:
 
 
 workflows:
+  lint:
+    jobs:
+      - lint_python_and_config
   build:
     jobs:
       - circleci_consistency

.clang-format

@@ -0,0 +1,88 @@
+---
+AccessModifierOffset: -1
+AlignAfterOpenBracket: AlwaysBreak
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlinesLeft: true
+AlignOperands:   false
+AlignTrailingComments: false
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Empty
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: false
+BinPackParameters: false
+BraceWrapping:
+  AfterClass:      false
+  AfterControlStatement: false
+  AfterEnum:       false
+  AfterFunction:   false
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     false
+  BeforeElse:      false
+  IndentBraces:    false
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Attach
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+BreakAfterJavaFieldAnnotations: false
+BreakStringLiterals: false
+ColumnLimit:     80
+CommentPragmas:  '^ IWYU pragma:'
+CompactNamespaces: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ForEachMacros:   [ FOR_EACH_RANGE, FOR_EACH, ]
+IncludeCategories:
+  - Regex:           '^<.*\.h(pp)?>'
+    Priority:        1
+  - Regex:           '^<.*'
+    Priority:        2
+  - Regex:           '.*'
+    Priority:        3
+IndentCaseLabels: true
+IndentWidth:     2
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBlockIndentWidth: 2
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: false
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 2000000
+PointerAlignment: Left
+ReflowComments:  true
+SortIncludes:    true
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Cpp11
+TabWidth:        8
+UseTab:          Never
+...

.pre-commit-config.yaml

@@ -0,0 +1,26 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.0.1
+    hooks:
+      - id: check-docstring-first
+      - id: check-toml
+      - id: check-yaml
+        exclude: packaging/.*
+      - id: mixed-line-ending
+        args: [--fix=lf]
+      - id: end-of-file-fixer
+
+
+  - repo: https://github.com/omnilib/ufmt
+    rev: v1.3.0
+    hooks:
+      - id: ufmt
+        additional_dependencies:
+          - black == 21.9b0
+          - usort == 0.6.4
+
+
+  -   repo: https://github.com/pre-commit/mirrors-clang-format
+      rev: v13.0.0
+      hooks:
+      -   id: clang-format

pyproject.toml

@@ -0,0 +1,10 @@
+[tool.usort]
+
+first_party_detection = false
+
+[tool.black]
+
+line-length = 120
+target-version = ["py37"]
+
+[tool.ufmt]