From c17ea027c810272b6749eb454164275d048d73c8 Mon Sep 17 00:00:00 2001
From: KotlinIsland <kotlinisland@users.noreply.github.com>
Date: Wed, 28 Apr 2021 10:26:15 +1000
Subject: [PATCH] git hook: add version number and validation

---
 CHANGELOG.md                                      |  2 +-
 .../org/jlleitschuh/gradle/ktlint/GitHook.kt      | 15 ++++++++++++++-
 .../gradle/ktlint/tasks/BaseKtLintCheckTask.kt    |  4 ++++
 .../jlleitschuh/gradle/ktlint/GitHookTasksTest.kt | 11 +++++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa60201d..025e5473 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [10.1.0-SNAPSHOT] Unreleased
 ### Added
-  - ?
+  - Added git hook update notifier ([#474](https://github.com/JLLeitschuh/ktlint-gradle/pull/474))
 ### Changed
   - Updated Gradle to `6.8.3` version
   - Updated default KtLint version to `0.41.0`
diff --git a/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/GitHook.kt b/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/GitHook.kt
index 732b2bff..658316e1 100644
--- a/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/GitHook.kt
+++ b/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/GitHook.kt
@@ -12,6 +12,19 @@ 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+ * When this value is passed to the gradle task it is validated to ensure users don't have outdated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 =
     """
@@ -32,7 +45,7 @@ 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(
diff --git a/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/tasks/BaseKtLintCheckTask.kt b/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/tasks/BaseKtLintCheckTask.kt
index ac8601e2..53e3d607 100644
--- a/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/tasks/BaseKtLintCheckTask.kt
+++ b/plugin/src/main/kotlin/org/jlleitschuh/gradle/ktlint/tasks/BaseKtLintCheckTask.kt
@@ -30,6 +30,7 @@ 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
@@ -88,6 +89,9 @@ abstract class BaseKtLintCheckTask @Inject constructor(
     }
 
     init {
+        if (project.findProperty(hookVersion)?.equals(hookVersion) == false) {
+            throw GradleException("Your ktlint git hook is outdated, please update by running the addKtlint*GitPreCommitHook Gradle task.")
+        }
         if (project.hasProperty(FILTER_INCLUDE_PROPERTY_NAME)) {
             applyGitFilter()
         } else {
diff --git a/plugin/src/test/kotlin/org/jlleitschuh/gradle/ktlint/GitHookTasksTest.kt b/plugin/src/test/kotlin/org/jlleitschuh/gradle/ktlint/GitHookTasksTest.kt
index ea4005dc..6e919779 100644
--- a/plugin/src/test/kotlin/org/jlleitschuh/gradle/ktlint/GitHookTasksTest.kt
+++ b/plugin/src/test/kotlin/org/jlleitschuh/gradle/ktlint/GitHookTasksTest.kt
@@ -184,6 +184,17 @@ 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()