feat: add IntelliJ IDEA formatter

.github/workflows/ci.yml

@@ -59,6 +59,9 @@ jobs:
             jre: 11
             os: ubuntu-latest
             shfmt-version: v3.8.0
+          - kind: idea
+            jre: 11
+            os: ubuntu-latest
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
@@ -91,6 +94,16 @@ jobs:
       - name: Test shfmt
         if: matrix.kind == 'shfmt'
         run: ./gradlew testShfmt
+      - name: Test idea
+        if: matrix.kind == 'idea'
+        run: |
+          download_link=$(curl https://data.services.jetbrains.com/products/releases\?code\=IIC\&latest\=true\&type\=release | jq -r '.IIC[0].downloads.linux.link')
+          curl --location "$download_link" -o idea.tar.gz
+          tar -xf idea.tar.gz
+          cd idea-IC*
+          export PATH=${PATH}:$(pwd)/bin
+          cd ..
+          ./gradlew testIdea
       - name: junit result
         uses: mikepenz/action-junit-report@v5
         if: always() # always run even if the previous step fails

.gitignore

@@ -7,6 +7,7 @@
 # Project-specific stuff
 userHome/
 workspace/
+testenv.properties
 
 ### Gradle ###
 .gradle

CHANGES.md

@@ -11,6 +11,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 ### Added
+* Support for `idea` ([#2020](https://github.com/diffplug/spotless/pull/2020), [#2535](https://github.com/diffplug/spotless/pull/2535))
 * Add support for removing wildcard imports via `removeWildcardImports` step. ([#2517](https://github.com/diffplug/spotless/pull/2517))
 
 ## [3.1.2] - 2025-05-27

INTELLIJ_IDEA_SCREENSHOTS.md

@@ -0,0 +1,16 @@
+# Extracting Code Style from IntelliJ IDEA
+
+## 1. Exporting Code Style Settings to a file
+To export code style settings from IntelliJ IDEA to a file, go to
+`Settings | Editor | Code Style` and click on the gear icon next to the scheme name.
+
+![Exporting code style settings](_images/intellij_export_codestyle.png)
+
+## 2. Using IntelliJ's active code style directly
+If you have your code style settings checked into version control (in your `.idea` directory), 
+you can use the active code style directly in Spotless without exporting it to a file. 
+The file can be found at `.idea/codeStyles/Project.xml`.
+
+## Upstream documentation
+More details can be found in the [IntelliJ IDEA documentation](https://www.jetbrains.com/help/idea/command-line-formatter.html#options)
+for the command line formatter, which is what Spotless uses under the hood.

gradle/special-tests.gradle

@@ -6,6 +6,7 @@ def special = [
 	'buf',
 	'clang',
 	'gofmt',
+	'idea',
 	'npm',
 	'shfmt'
 ]
@@ -37,5 +38,9 @@ tasks.named('test').configure {
 special.forEach { tag ->
 	tasks.register("test${tag.capitalize()}", Test) {
 		useJUnitPlatform { includeTags tag }
+		if (rootProject.file('testenv.properties').exists()) {
+			systemProperty 'testenv.properties.path', rootProject.file('testenv.properties').canonicalPath
+		}
 	}
 }
+