clang-format

I tried for a while to come up with a config that perfectly matched
the existing style and the closest I could get changed about 15% of
the lines and looked bad on moderately indented blocks because of
the use of tabs. Moving away from tabs changes more lines, but looks
better.

Author: flowerysong

.clang-format

@@ -0,0 +1,30 @@
+AlignAfterOpenBracket: Align
+AlignArrayOfStructures: Left
+AlignConsecutiveDeclarations: AcrossEmptyLines
+AlignConsecutiveMacros: AcrossEmptyLinesAndComments
+AllowShortBlocksOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterReturnType: AllDefinitions
+BinPackArguments: true
+BinPackParameters: false
+BraceWrapping:
+    AfterCaseLabel: true
+    AfterControlStatement: Always
+    AfterEnum: true
+    AfterFunction: true
+    AfterStruct: true
+    AfterExternBlock: false
+    BeforeElse: true
+    BeforeWhile: true
+BreakBeforeBraces: Custom
+BreakStringLiterals: false
+ColumnLimit: 80
+IndentExternBlock: NoIndent
+IndentWidth: 4
+PenaltyBreakAssignment: 100
+PenaltyReturnTypeOnItsOwnLine: 150
+SpaceAfterCStyleCast: true
+TabWidth: 4
+UseTab: Never

.editorconfig

@@ -7,7 +7,8 @@ insert_final_newline = true
 charset = utf-8
 
 [*.{c,h}]
-indent_style = tab
+indent_style = space
+indent_size = 4
 
 [*.py]
 indent_style = space

.github/workflows/build.yml

@@ -4,6 +4,18 @@ on:
   pull_request:
 
 jobs:
+  clang_format:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v4
+
+      - name: Lint code formatting
+        run: |
+          clang-format-15 -i */*.[ch]
+          git diff
+          git status --porcelain | grep -q '^ M' && exit 1 || exit 0
+
   flake8:
     runs-on: ubuntu-latest
     steps:
@@ -26,7 +38,7 @@ jobs:
         run: sudo apt update
 
       - name: Install dependencies
-        run: sudo apt install libbsd-dev libjansson-dev libmilter-dev libssl-dev
+        run: sudo apt install libbsd-dev libidn2-dev libjansson-dev libmilter-dev libssl-dev
 
       - name: Install Python dependencies
         run: sudo pip install pytest miltertest