Add git hook version

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [10.3.0-SNAPSHOT] - Unreleased
 ### Added
+  - Added git hook update notifier ([#474](https://github.com/JLLeitschuh/ktlint-gradle/pull/474))
   - ?
 
 ### Changed

plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/GitHook.kt

@@ -15,6 +15,19 @@ import javax.inject.Inject
 
 internal const val FILTER_INCLUDE_PROPERTY_NAME = "internalKtlintGitFilter"
 
+/**
+ * The version of the git hook,
+ *
+ * When this value is passed to the gradle task it is validated to ensure users don't have outdated
+ * ktlint git hooks installed.
+ *
+ * This should be manually updated when changes are made to the git hook.
+ *
+ * TODO: Implement a CI/build step that will look for changes to either GitHook.kt or the git hook output and
+ *   automatically increment this value
+ */
+internal const val hookVersion = "1"
+
 @Language("Bash")
 internal val shShebang =
     """
@@ -34,7 +47,7 @@ private fun generateGradleCommand(
     } else {
         "./gradlew"
     }
-    return "$gradleCommand --quiet $taskName -P$FILTER_INCLUDE_PROPERTY_NAME=\"${'$'}CHANGED_FILES\""
+    return "$gradleCommand --quiet $taskName -P$FILTER_INCLUDE_PROPERTY_NAME=\"${'$'}CHANGED_FILES\" -phookVersion=$hookVersion"
 }
 
 private fun generateGitCommand(
@@ -54,7 +67,7 @@ private fun postCheck(
             git add ${'$'}file
         fi
     done
-    """.trimIndent()
+    """.trim('\n', ' ')
 } else {
     ""
 }
@@ -90,6 +103,7 @@ internal fun generateGitHook(
     $gradleCommandExitCode=$?
 
     echo "Completed ktlint run."
+
     ${postCheck(shouldUpdateCommit)}
 
     if [ -s ${'$'}diff ]; then

plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/tasks/BaseKtLintCheckTask.kt

@@ -33,6 +33,7 @@ import org.jlleitschuh.gradle.ktlint.FILTER_INCLUDE_PROPERTY_NAME
 import org.jlleitschuh.gradle.ktlint.KOTLIN_EXTENSIONS
 import org.jlleitschuh.gradle.ktlint.applyGitFilter
 import org.jlleitschuh.gradle.ktlint.getEditorConfigFiles
+import org.jlleitschuh.gradle.ktlint.hookVersion
 import org.jlleitschuh.gradle.ktlint.intermediateResultsBuildDir
 import org.jlleitschuh.gradle.ktlint.property
 import org.jlleitschuh.gradle.ktlint.worker.KtLintWorkAction
@@ -96,6 +97,10 @@ abstract class BaseKtLintCheckTask @Inject constructor(
 
     init {
         if (project.hasProperty(FILTER_INCLUDE_PROPERTY_NAME)) {
+            // if FILTER_INCLUDE_PROPERTY_NAME exists then we are invoked from a git hook, check hook version
+            if (project.findProperty(hookVersion) != hookVersion) {
+                logger.warn("Your ktlint git hook is outdated, please update by running the addKtlint*GitPreCommitHook Gradle task.")
+            }
             applyGitFilter()
         } else {
             KOTLIN_EXTENSIONS.forEach {

plugin/src/test/kotlin/org/jlleitschuh/gradle/ktlint/GitHookTasksTest.kt

@@ -271,6 +271,23 @@ class GitHookTasksTest : AbstractPluginTest() {
         }
     }
 
+    @Test
+    internal fun `Git hook should send the hook version to gradle`() {
+        projectRoot.setupGradleProject()
+        val gitDir = projectRoot.initGit()
+
+        build(":$INSTALL_GIT_HOOK_FORMAT_TASK").run {
+            assertThat(task(":$INSTALL_GIT_HOOK_FORMAT_TASK")?.outcome).isEqualTo(TaskOutcome.SUCCESS)
+            assertThat(gitDir.preCommitGitHook().readText()).contains("""-phookVersion=$hookVersion""")
+        }
+    }
+
+    private fun File.initGit(): File {
+        val repo = RepositoryBuilder().setWorkTree(this).setMustExist(false).build()
+        repo.create()
+        return repo.directory
+    }
+
     private fun File.preCommitGitHook(): File = gitHookFolder().resolve("pre-commit")
 
     private fun File.gitHookFolder(): File = resolve("hooks/")