Replace grgit with static method in buildSrc using JGit

Author: Choonster

.gitignore

@@ -13,4 +13,8 @@
 !.gitattributes
 !ASSETS_LICENSE.txt
 
+!buildSrc
+buildSrc/.gradle
+buildSrc/build
+
 src/generated/resources/\.cache/

build.gradle

@@ -1,3 +1,5 @@
+import choonster.testmod3.gradle.GitVersion;
+
 plugins {
     id 'java'
     id 'idea'
@@ -6,16 +8,9 @@ plugins {
     id 'net.minecraftforge.accesstransformers' version '5.0.1'
     id 'net.minecraftforge.gradle' version '7.0.0-beta.51'
     id 'net.minecraftforge.jarjar' version '0.2.3'
-    id 'org.ajoberstar.grgit' version '5.2.0'
 }
 
-final commitId
-
-if (hasProperty("grgit")) { // If there's a valid Git repository, get the latest commit ID
-    commitId = "${grgit.head().abbreviatedId}"
-} else { // Else fall back to NOGIT
-    commitId = "NOGIT"
-}
+final def commitId = GitVersion.getGitCommit(layout.projectDirectory.asFile).orElse("NOGIT");
 
 mod_version = "${minecraft_version}-${mod_version}-${commitId}"
 

buildSrc/build.gradle

@@ -0,0 +1,7 @@
+repositories {
+    mavenCentral();
+}
+
+dependencies {
+    implementation "org.eclipse.jgit:org.eclipse.jgit:7.4.0.202509020913-r"
+}

buildSrc/src/main/java/choonster/testmod3/gradle/GitVersion.java

@@ -0,0 +1,42 @@
+package choonster.testmod3.gradle;
+
+import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Optional;
+
+public class GitVersion {
+	static Optional<String> getGitCommit(final File projectDir) {
+		final var gitDir = new File(projectDir, ".git");
+
+		if (!gitDir.exists()) {
+			return Optional.empty();
+		}
+
+		final var builder = new FileRepositoryBuilder();
+		builder.readEnvironment();
+
+		builder.findGitDir(projectDir);
+
+		if (builder.getGitDir() == null) {
+			throw new IllegalStateException("No .git directory found!");
+		}
+
+		try (
+				final var repository = builder.build();
+				final var reader = repository.newObjectReader()
+		) {
+			final var head = repository.resolve("HEAD");
+
+			if (head == null) {
+				return Optional.empty();
+			}
+
+			final var abbreviated = reader.abbreviate(head);
+			return Optional.of(abbreviated.name());
+		} catch (final IOException e) {
+			throw new IllegalStateException("Failed to get commit from Git repository", e);
+		}
+	}
+}