add git extension

README.md

@@ -2,6 +2,10 @@
 
 ## Extension
 
+### Extension Git
+
+The GitExtension enhances versioning by dynamically appending the Git hash before "snapshot" in the version string. For example, 0.0.0-SNAPSHOT becomes 0.0.0.0a2b3c4d-SNAPSHOT, ensuring each build reflects its commit origin, prevents overwriting existing versions. This feature aids developers during development by providing clear version identification.
+
 ## Publish version catalog locally.
 
 ```shell

build.gradle.kts

@@ -17,7 +17,11 @@ plugins {
 }
 
 dependencies {
+    implementation(aa.jgit)
+
+    testImplementation(aa.junit.jupiter.params)
     testImplementation(aa.kotlin.junit5)
+    testImplementation(aa.mockk)
 
     testRuntimeOnly(aa.junit.platform.launcher)
 }

src/main/kotlin/ltd/lulz/plugin/CorePlugin.kt

@@ -1,7 +1,9 @@
 package ltd.lulz.plugin
 
+import ltd.lulz.plugin.extension.GitExtension
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import ltd.lulz.plugin.extension.GitExtension.Companion.PLUGIN_NAME as GIT_PLUGIN_NAME
 
 @Suppress("unused")
 class CorePlugin : Plugin<Project> {
@@ -12,6 +14,11 @@ class CorePlugin : Plugin<Project> {
     override fun apply(
         project: Project,
     ) {
-        TODO("Not yet implemented")
+        gitExtension(project)
     }
+
+    private fun gitExtension(
+        project: Project,
+    ): GitExtension = project.extensions
+        .create(GIT_PLUGIN_NAME, GitExtension::class.java, project)
 }

src/main/kotlin/ltd/lulz/plugin/extension/GitExtension.kt

@@ -0,0 +1,37 @@
+package ltd.lulz.plugin.extension
+
+import org.eclipse.jgit.api.Git.open
+import org.eclipse.jgit.lib.Constants.HEAD
+import org.gradle.api.Project
+
+abstract class GitExtension(private val project: Project) {
+
+    companion object {
+        const val PLUGIN_NAME = "git"
+
+        private const val HASH_LENGTH = 8
+        private const val SNAPSHOT = "-SNAPSHOT"
+        private const val UNAVAILABLE = "n/a"
+        private val PRIMARY_BRANCHES = setOf("master", "develop")
+    }
+
+    fun version(): String = when {
+        isHead() || currentBranch() in PRIMARY_BRANCHES -> project.version.toString()
+        else -> makeVersion(project.version.toString(), currentShortHash())
+    }
+
+    fun currentShortHash(): String = open(project.projectDir)
+        .use { it.repository.exactRef(HEAD)?.objectId?.name?.take(HASH_LENGTH) ?: UNAVAILABLE }
+
+    fun currentBranch(): String = open(project.projectDir)
+        .use { it.repository.branch ?: UNAVAILABLE }
+
+    fun isHead(): Boolean = open(project.projectDir)
+        .use { it.repository.exactRef(HEAD)?.target?.name == HEAD }
+
+    private fun makeVersion(version: String, shortHash: String): String = when {
+        shortHash == UNAVAILABLE -> version.also { println("Failed to get data from GIT") }
+        version.endsWith(SNAPSHOT) -> version.replace(SNAPSHOT, ".$shortHash$SNAPSHOT")
+        else -> version.also { println("Failed version missing suffix $SNAPSHOT") }
+    }
+}

src/test/kotlin/ltd/lulz/plugin/extension/GitExtensionTest.kt

@@ -0,0 +1,162 @@
+package ltd.lulz.plugin.extension
+
+import io.mockk.every
+import io.mockk.justRun
+import io.mockk.mockk
+import io.mockk.mockkStatic
+import io.mockk.unmockkStatic
+import org.eclipse.jgit.api.Git
+import org.eclipse.jgit.lib.ObjectId
+import org.eclipse.jgit.lib.Ref
+import org.eclipse.jgit.lib.Repository
+import org.gradle.api.Project
+import org.gradle.testfixtures.ProjectBuilder
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+
+class GitExtensionTest {
+    companion object {
+        const val GIT_HASH_SHA_1 = "0a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t"
+        const val SHORT_GIT_HASH = "0a1b2c3d"
+        const val SNAPSHOT_HASH_VERSION = "0.0.0.0a1b2c3d-SNAPSHOT"
+        const val SNAPSHOT_VERSION = "0.0.0-SNAPSHOT"
+        const val VERSION = "0.0.0"
+
+        const val BRANCH_FEATURE = "feature/ABC-123"
+        const val BRANCH_MASTER = "master"
+        const val EXTENSION = "git"
+        const val PLUGIN_ID = "ltd.lulz.plugin.core-plugin"
+        const val REF_HEAD = "HEAD"
+        const val UNAVAILABLE = "n/a"
+    }
+
+    private val gitMock: Git = mockk()
+    private val refMock: Ref = mockk()
+    private val repositoryMock: Repository = mockk()
+    private val objectIdMock: ObjectId = mockk()
+
+    lateinit var name: String
+    lateinit var project: Project
+
+    @BeforeEach
+    fun buildUp() {
+        project = ProjectBuilder.builder().build()
+        project.version = SNAPSHOT_VERSION
+        project.pluginManager.apply(PLUGIN_ID)
+        mockkStatic(Git::class)
+
+        every { Git.open(any()) } returns gitMock
+        every { gitMock.repository } returns repositoryMock
+        every { repositoryMock.branch } returns null
+        every { repositoryMock.exactRef(any()) } returns refMock
+        every { refMock.target } returns refMock
+        every { refMock.name } returns null
+        every { refMock.objectId } returns objectIdMock
+        every { objectIdMock.name } returns null
+
+        justRun { gitMock.close() }
+    }
+
+    @AfterEach
+    fun tearDown() {
+        unmockkStatic(Git::class)
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        "$REF_HEAD, true",
+        "$BRANCH_FEATURE, false",
+    )
+    fun `current ref is head`(ref: String, expected: Boolean) {
+        // given
+        every { refMock.name } returns ref
+
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(expected, extension.isHead())
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        ", $UNAVAILABLE",
+        "$BRANCH_FEATURE, $BRANCH_FEATURE",
+    )
+    fun `get current branch`(branch: String?, expected: String) {
+        // given
+        every { repositoryMock.branch } returns branch
+
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(expected, extension.currentBranch())
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        ", $UNAVAILABLE",
+        "$GIT_HASH_SHA_1, $SHORT_GIT_HASH",
+    )
+    fun `get current short hash`(hash: String?, expected: String) {
+        // given
+        every { objectIdMock.name } returns hash
+
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(expected, extension.currentShortHash())
+    }
+
+    @Test
+    fun `get version - version without snapshot`() {
+        // given
+        project.version = VERSION
+        every { objectIdMock.name } returns GIT_HASH_SHA_1
+
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(VERSION, extension.version())
+    }
+
+    @Test
+    fun `get version - short hash is blank`() {
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(SNAPSHOT_VERSION, extension.version())
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        ", , $SNAPSHOT_HASH_VERSION",
+        ", $REF_HEAD, $SNAPSHOT_VERSION",
+        "$BRANCH_MASTER, , $SNAPSHOT_VERSION",
+        "$BRANCH_MASTER, , $SNAPSHOT_VERSION",
+        "$BRANCH_FEATURE, , $SNAPSHOT_HASH_VERSION",
+        "$BRANCH_MASTER, $REF_HEAD, $SNAPSHOT_VERSION",
+        "$BRANCH_MASTER, $REF_HEAD, $SNAPSHOT_VERSION",
+        "$BRANCH_FEATURE, $REF_HEAD, $SNAPSHOT_VERSION",
+    )
+    fun `get version - different branches`(branch: String?, ref: String?, expected: String) {
+        // given
+        every { repositoryMock.branch } returns branch
+        every { objectIdMock.name } returns GIT_HASH_SHA_1
+        every { refMock.name } returns ref
+
+        // when
+        val extension = project.extensions.getByName(EXTENSION) as GitExtension
+
+        // then
+        assertEquals(expected, extension.version())
+    }
+}