From ff53c45a0e58f1291af5f0bdb2584669d26409b6 Mon Sep 17 00:00:00 2001
From: Brice Jaglin <bjaglin@teads.tv>
Date: Mon, 6 Jul 2020 13:40:39 +0200
Subject: [PATCH] prevent failure on sbt init when JGit finds a .git with no
 commit

2ca68e4 exposed failure to lookup commits during sbt initialization,
while it would only happen on `scalafix` invocation earlier.
---
 .../internal/sbt/JGitCompletions.scala        |  4 ++-
 .../internal/sbt/JGitCompletionsSuite.scala   | 28 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 src/test/scala/scalafix/internal/sbt/JGitCompletionsSuite.scala

diff --git a/src/main/scala/scalafix/internal/sbt/JGitCompletions.scala b/src/main/scala/scalafix/internal/sbt/JGitCompletions.scala
index aebc90af..f473a068 100644
--- a/src/main/scala/scalafix/internal/sbt/JGitCompletions.scala
+++ b/src/main/scala/scalafix/internal/sbt/JGitCompletions.scala
@@ -11,6 +11,7 @@ import org.eclipse.jgit.util.GitDateFormatter
 
 import java.nio.file.Path
 import scala.collection.JavaConverters._
+import scala.util.Try
 
 class JGitCompletion(cwd: Path) {
   private val isGitRepository =
@@ -24,7 +25,8 @@ class JGitCompletion(cwd: Path) {
       val refList0 =
         repo.getRefDatabase().getRefsByPrefix(RefDatabase.ALL).asScala
       val git = new Git(repo)
-      val refs0 = git.log().setMaxCount(20).call().asScala.toList
+      val refs0 =
+        Try(git.log().setMaxCount(20).call().asScala.toList).getOrElse(Nil)
       (refList0, refs0)
     } else {
       (Nil, Nil)
diff --git a/src/test/scala/scalafix/internal/sbt/JGitCompletionsSuite.scala b/src/test/scala/scalafix/internal/sbt/JGitCompletionsSuite.scala
new file mode 100644
index 00000000..54cfe36d
--- /dev/null
+++ b/src/test/scala/scalafix/internal/sbt/JGitCompletionsSuite.scala
@@ -0,0 +1,28 @@
+package scalafix.internal.sbt
+
+import org.eclipse.jgit.api.{Git => JGit}
+import org.scalatest.funsuite.AnyFunSuite
+
+class JGitCompletionsSuite extends AnyFunSuite {
+
+  test("directory with no .git") {
+    val fs = new Fs()
+    val jgit = new JGitCompletion(fs.workingDirectory)
+    assert(jgit.last20Commits == Nil)
+  }
+
+  test("directory with empty .git") {
+    val fs = new Fs()
+    fs.mkdir(".git")
+    val jgit = new JGitCompletion(fs.workingDirectory)
+    assert(jgit.last20Commits == Nil)
+  }
+
+  test("directory with no commits") {
+    val fs = new Fs()
+    JGit.init().setDirectory(fs.workingDirectory.toFile).call() // git init
+    val jgit = new JGitCompletion(fs.workingDirectory)
+    assert(jgit.last20Commits == Nil)
+  }
+
+}