@@ -293,9 +293,17 @@ func calcCopyInfo(b *Builder, cmdName string, ci *copyInfo, allowRemote bool, al

 			return err

 		} else if fi.IsDir() {

 			var subfiles []string

+			absOrigPath := path.Join(b.contextPath, ci.origPath)

+

+			// Add a trailing / to make sure we only

+			// pick up nested files under the dir and

+			// not sibling files of the dir that just

+			// happen to start with the same chars

+			if !strings.HasSuffix(absOrigPath, "/") {

+				absOrigPath += "/"

+			}

 			for _, fileInfo := range sums {

 				absFile := path.Join(b.contextPath, fileInfo.Name())

-				absOrigPath := path.Join(b.contextPath, ci.origPath)

 				if strings.HasPrefix(absFile, absOrigPath) {

 					subfiles = append(subfiles, fileInfo.Sum())

 				}

@@ -1175,6 +1175,37 @@ func TestBuildADDLocalFileWithoutCache(t *testing.T) {

 	logDone("build - add local file without cache")

 }

+func TestBuildCopyDirButNotFile(t *testing.T) {

+	name := "testbuildcopydirbutnotfile"

+	defer deleteImages(name)

+	dockerfile := `

+        FROM scratch

+        COPY dir /tmp/`

+	ctx, err := fakeContext(dockerfile, map[string]string{

+		"dir/foo": "hello",

+	})

+	defer ctx.Close()

+	if err != nil {

+		t.Fatal(err)

+	}

+	id1, err := buildImageFromContext(name, ctx, true)

+	if err != nil {

+		t.Fatal(err)

+	}

+	// Check that adding file with similar name doesn't mess with cache

+	if err := ctx.Add("dir_file", "hello2"); err != nil {

+		t.Fatal(err)

+	}

+	id2, err := buildImageFromContext(name, ctx, true)

+	if err != nil {

+		t.Fatal(err)

+	}

+	if id1 != id2 {

+		t.Fatal("The cache should have been used but wasn't")

+	}

+	logDone("build - add current directory but not file")

+}

+

 func TestBuildADDCurrentDirWithCache(t *testing.T) {

 	name := "testbuildaddcurrentdirwithcache"

 	defer deleteImages(name)