From 3359be16e5e277ae6d0082fb09c446d7648854ca Mon Sep 17 00:00:00 2001
From: gongxuanzhang <gongxuanzhangmelt@gmail.com>
Date: Mon, 3 Jun 2024 04:02:07 +0800
Subject: [PATCH] KAFKA-10787 Add import ordering checkstyle rule and configure
 an automatic formatter (#16097)

Reviewers: Chia-Ping Tsai <chia7712@gmail.com>
---
 README.md                 |  7 ++++++-
 build.gradle              | 17 ++++++++++++++++-
 checkstyle/checkstyle.xml |  2 ++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 27ce0dc0bce64..ab7dcd7685bde 100644
--- a/README.md
+++ b/README.md
@@ -227,11 +227,16 @@ There are two code quality analysis tools that we regularly run, spotbugs and ch
 Checkstyle enforces a consistent coding style in Kafka.
 You can run checkstyle using:
 
-    ./gradlew checkstyleMain checkstyleTest
+    ./gradlew checkstyleMain checkstyleTest spotlessCheck
 
 The checkstyle warnings will be found in `reports/checkstyle/reports/main.html` and `reports/checkstyle/reports/test.html` files in the
 subproject build directories. They are also printed to the console. The build will fail if Checkstyle fails.
 
+#### Spotless ####
+The import order is a part of static check. please call `spotlessApply` to optimize the imports of Java codes before filing pull request :
+
+    ./gradlew spotlessApply
+
 #### Spotbugs ####
 Spotbugs uses static analysis to look for bugs in the code.
 You can run spotbugs using:
diff --git a/build.gradle b/build.gradle
index ea168ecb26fb4..a2a6531d29a62 100644
--- a/build.gradle
+++ b/build.gradle
@@ -47,7 +47,9 @@ plugins {
   // Updating the shadow plugin version to 8.1.1 causes issue with signing and publishing the shadowed
   // artifacts - see https://github.com/johnrengelman/shadow/issues/901
   id 'com.github.johnrengelman.shadow' version '8.1.0' apply false
-  id 'com.diffplug.spotless' version '6.14.0' apply false // 6.14.1 and newer require Java 11 at compile time, so we can't upgrade until AK 4.0
+  //  the minimum required JRE of 6.14.0+ is 11
+  //  refer:https://github.com/diffplug/spotless/tree/main/plugin-gradle#requirements
+  id 'com.diffplug.spotless' version "6.13.0" apply false
 }
 
 ext {
@@ -198,6 +200,9 @@ def determineCommitId() {
   }
 }
 
+def spotlessApplyModules = ['']
+
+
 apply from: file('wrapper.gradle')
 
 if (repo != null) {
@@ -793,6 +798,16 @@ subprojects {
     skipProjects = [ ":jmh-benchmarks", ":trogdor" ]
     skipConfigurations = [ "zinc" ]
   }
+
+  if (project.name in spotlessApplyModules) {
+    apply plugin: 'com.diffplug.spotless'
+    spotless {
+      java {
+        importOrder('kafka', 'org.apache.kafka', 'com', 'net', 'org', 'java', 'javax', '', '\\#')
+        removeUnusedImports()
+      }
+    }
+  }
 }
 
 gradle.taskGraph.whenReady { taskGraph ->
diff --git a/checkstyle/checkstyle.xml b/checkstyle/checkstyle.xml
index aff659638928b..61eb7e4b245fd 100644
--- a/checkstyle/checkstyle.xml
+++ b/checkstyle/checkstyle.xml
@@ -82,6 +82,8 @@
       <property name="file" value="${config_loc}/${importControlFile}"/>
     </module>
 
+    <!--   don't define any import order here! Import order check/format is addressed by spotless.-->
+
     <!-- whitespace -->
     <module name="GenericWhitespace"/>
     <module name="NoWhitespaceBefore"/>