Add Kotlin formatting to Spotless

ratchetFrom means Spotless will apply only to files which have changed since origin/main

It also means we need to make some changes to CI due to ensure builds pass due to shallow clones. See https://github.com/diffplug/spotless/tree/main/plugin-gradle#using-ratchetfrom-on-ci-systems for more details.

Author: mikescamell

.editorconfig

@@ -91,3 +91,7 @@ ij_kotlin_while_on_new_line = false
 ij_kotlin_wrap_elvis_expressions = 1
 ij_kotlin_wrap_expression_body_functions = 1
 ij_kotlin_wrap_first_method_in_call_chain = false
+ktlint_standard_no-wildcard-imports = disabled
+ktlint_standard_filename = disabled
+ktlint_standard_package-name = disabled
+ktlint_standard_annotation = disabled

.github/workflows/ci.yml

@@ -27,6 +27,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          fetch-depth: 0 # required due to setting Spotless ratchetFrom
           submodules: recursive
 
       - name: Set up JDK version
@@ -39,7 +40,7 @@ jobs:
         uses: gradle/actions/setup-gradle@v3
 
       - name: Run Code Formatting Checks
-        run: ./gradlew code_format_checks
+        run: ./gradlew spotlessCheck
 
   unit_tests:
     name: Unit tests

.github/workflows/nightly.yml

@@ -18,6 +18,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          fetch-depth: 0 # required due to setting Spotless ratchetFrom
           submodules: recursive
 
       - name: Set up JDK version
@@ -30,7 +31,7 @@ jobs:
         uses: gradle/actions/setup-gradle@v3
 
       - name: Run Code Formatting Checks
-        run: ./gradlew code_format_checks
+        run: ./gradlew spotlessCheck
 
   unit_tests:
     name: Unit tests

code-formatting.gradle

@@ -1,6 +1,13 @@
 apply plugin: 'com.diffplug.spotless'
 
 spotless {
+    ratchetFrom 'origin/develop'
+    kotlin {
+        target 'src/*/kotlin/**/*.kt', 'src/*/java/**/*.kt'
+        ktlint("1.7.1")
+        trimTrailingWhitespace()
+        indentWithSpaces()
+    }
     java {
         target 'src/*/java/**/*.java'
         googleJavaFormat('1.22.0').aosp()