From a73c3366bf83e2313c09614307d95f61f7d14075 Mon Sep 17 00:00:00 2001
From: Ethan Atkins <contact@ethanatkins.com>
Date: Tue, 21 Jan 2020 12:11:08 -0800
Subject: [PATCH] Correctly exclude base from Path.allSubpaths result

It was reported in https://github.com/scala/scala/pull/8525 that sbt
does not correctly exclude the base directory when calling
Path.allSubpaths. This ended up causing jar files to be created with an
empty entry. The problem was in an incorrect equality check because the
compiler did not flag for us that
`PathFinder(base).globRecursive(filter).get()` returned `Seq[File]` but
that we were filtering the results by comparing a `File` to a `Path`.
---
 io/src/main/scala/sbt/io/PathMapper.scala     | 6 ++----
 io/src/test/scala/sbt/io/PathMapperSpec.scala | 7 +++++++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/io/src/main/scala/sbt/io/PathMapper.scala b/io/src/main/scala/sbt/io/PathMapper.scala
index 78c51c20..25bbd964 100644
--- a/io/src/main/scala/sbt/io/PathMapper.scala
+++ b/io/src/main/scala/sbt/io/PathMapper.scala
@@ -112,12 +112,10 @@ abstract class Mapper {
    * Selects descendants of `base` directory matching `filter` and maps them to a path relative to `base`.
    * `base` itself is not included.
    */
-  def selectSubpaths(base: File, filter: FileFilter): Traversable[(File, String)] = {
-    val path = base.toPath
+  def selectSubpaths(base: File, filter: FileFilter): Traversable[(File, String)] =
     PathFinder(base).globRecursive(filter).get().collect {
-      case f if f != path => f -> path.relativize(f.toPath).toString
+      case f if f != base => f -> base.toPath.relativize(f.toPath).toString
     }
-  }
 
   /**
    * return a Seq of mappings which effect is to add a whole directory in the generated package
diff --git a/io/src/test/scala/sbt/io/PathMapperSpec.scala b/io/src/test/scala/sbt/io/PathMapperSpec.scala
index 8b282572..ed533ef3 100644
--- a/io/src/test/scala/sbt/io/PathMapperSpec.scala
+++ b/io/src/test/scala/sbt/io/PathMapperSpec.scala
@@ -128,6 +128,13 @@ class PathMapperSpec extends fixture.FlatSpec with Matchers {
     mappings should be(empty)
   }
 
+  it should "not include the base directory" in { tempDirectory =>
+    val file = Files.createFile(tempDirectory.resolve("file"))
+    val paths = Path.allSubpaths(tempDirectory.toFile).toVector.map(_._1.toPath).toSet
+    assert(paths.contains(file))
+    assert(!paths.contains(tempDirectory))
+  }
+
   override protected def withFixture(test: OneArgTest): Outcome = {
     val tmpDir = Files.createTempDirectory("path-mappings")
     try {