From 06f27384dd74fe8705933108274f6a6dfa8732cd Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Mon, 19 Apr 2021 16:48:51 +0100
Subject: [PATCH] b2: fix versions and .files with no extension - fixes #5244

---
 lib/version/version.go      | 18 ++++++++++++++----
 lib/version/version_test.go |  4 ++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/lib/version/version.go b/lib/version/version.go
index 2b13f6b44..6166e2262 100644
--- a/lib/version/version.go
+++ b/lib/version/version.go
@@ -13,10 +13,21 @@ const versionFormat = "-v2006-01-02-150405.000"
 
 var versionRegexp = regexp.MustCompile("-v\\d{4}-\\d{2}-\\d{2}-\\d{6}-\\d{3}")
 
+// Split fileName into base and extension so that base + ext == fileName
+func splitExt(fileName string) (base, ext string) {
+	ext = path.Ext(fileName)
+	base = fileName[:len(fileName)-len(ext)]
+	// .file splits to base == "", ext == ".file"
+	// so swap ext and base in this case
+	if ext != "" && base == "" {
+		base, ext = ext, base
+	}
+	return base, ext
+}
+
 // Add returns fileName modified to include t as the version
 func Add(fileName string, t time.Time) string {
-	ext := path.Ext(fileName)
-	base := fileName[:len(fileName)-len(ext)]
+	base, ext := splitExt(fileName)
 	s := t.Format(versionFormat)
 	// Replace the '.' with a '-'
 	s = strings.Replace(s, ".", "-", -1)
@@ -27,8 +38,7 @@ func Add(fileName string, t time.Time) string {
 // If the fileName did not have a version then time.Time{} is returned along with an unmodified fileName
 func Remove(fileName string) (t time.Time, fileNameWithoutVersion string) {
 	fileNameWithoutVersion = fileName
-	ext := path.Ext(fileName)
-	base := fileName[:len(fileName)-len(ext)]
+	base, ext := splitExt(fileName)
 	if len(base) < len(versionFormat) {
 		return
 	}
diff --git a/lib/version/version_test.go b/lib/version/version_test.go
index 7517fb329..d514b1918 100644
--- a/lib/version/version_test.go
+++ b/lib/version/version_test.go
@@ -26,6 +26,8 @@ func TestVersionAdd(t *testing.T) {
 		{t0, "potato-v2001-02-03-040506-123.txt", "potato-v2001-02-03-040506-123-v1970-01-01-010101-123.txt"},
 		{t0, "123.!!lipps", "123-v1970-01-01-010101-123.!!lipps"},
 		{t1, "potato", "potato-v2001-02-03-040506-123"},
+		{t1, ".potato", ".potato-v2001-02-03-040506-123"},
+		{t1, ".potato.conf", ".potato-v2001-02-03-040506-123.conf"},
 		{t1, "", "-v2001-02-03-040506-123"},
 	} {
 		actual := version.Add(test.in, test.t)
@@ -43,6 +45,8 @@ func TestVersionRemove(t *testing.T) {
 		{"potato-v1970-01-01-010101-123.txt", t0r, "potato.txt"},
 		{"potato-v2001-02-03-040506-123-v1970-01-01-010101-123.txt", t0r, "potato-v2001-02-03-040506-123.txt"},
 		{"potato-v2001-02-03-040506-123", t1, "potato"},
+		{".potato-v2001-02-03-040506-123", t1, ".potato"},
+		{".potato-v2001-02-03-040506-123.conf", t1, ".potato.conf"},
 		{"-v2001-02-03-040506-123", t1, ""},
 		{"potato-v2A01-02-03-040506-123", emptyT, "potato-v2A01-02-03-040506-123"},
 		{"potato-v2001-02-03-040506=123", emptyT, "potato-v2001-02-03-040506=123"},