Detect archive format from the file extension

The entire file name including the extension is used to detect the
format of the archive, like `archive.tar.gz` but this doesn't permit
the addition of more flexible routes that accept names like
`project-name-1.2.tar.gz`.

Only the extension of the file should be used to detect the archive
format so that more flexible archive routes are possible.

internal/git/archive.go

@@ -12,6 +12,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"regexp"
 	"time"
 
 	pb "gitlab.com/gitlab-org/gitaly-proto/go"
@@ -181,17 +182,26 @@ func finalizeCachedArchive(tempFile *os.File, archivePath string) error {
 	return nil
 }
 
+var (
+	patternZip    = regexp.MustCompile(`\.zip$`)
+	patternTar    = regexp.MustCompile(`\.tar$`)
+	patternTarGz  = regexp.MustCompile(`\.(tar\.gz|tgz|gz)$`)
+	patternTarBz2 = regexp.MustCompile(`\.(tar\.bz2|tbz|tbz2|tb2|bz2)$`)
+)
+
 func parseBasename(basename string) (pb.GetArchiveRequest_Format, bool) {
 	var format pb.GetArchiveRequest_Format
 
-	switch basename {
-	case "archive.zip":
+	switch {
+	case (basename == "archive"):
+		format = pb.GetArchiveRequest_TAR_GZ
+	case patternZip.MatchString(basename):
 		format = pb.GetArchiveRequest_ZIP
-	case "archive.tar":
+	case patternTar.MatchString(basename):
 		format = pb.GetArchiveRequest_TAR
-	case "archive", "archive.tar.gz", "archive.tgz", "archive.gz":
+	case patternTarGz.MatchString(basename):
 		format = pb.GetArchiveRequest_TAR_GZ
-	case "archive.tar.bz2", "archive.tbz", "archive.tbz2", "archive.tb2", "archive.bz2":
+	case patternTarBz2.MatchString(basename):
 		format = pb.GetArchiveRequest_TAR_BZ2
 	default:
 		return format, false

internal/git/archive_test.go

@@ -14,17 +14,17 @@ func TestParseBasename(t *testing.T) {
 		in  string
 		out pb.GetArchiveRequest_Format
 	}{
-		{"", pb.GetArchiveRequest_TAR_GZ},
-		{".tar.gz", pb.GetArchiveRequest_TAR_GZ},
-		{".tgz", pb.GetArchiveRequest_TAR_GZ},
-		{".gz", pb.GetArchiveRequest_TAR_GZ},
-		{".tar.bz2", pb.GetArchiveRequest_TAR_BZ2},
-		{".tbz", pb.GetArchiveRequest_TAR_BZ2},
-		{".tbz2", pb.GetArchiveRequest_TAR_BZ2},
-		{".tb2", pb.GetArchiveRequest_TAR_BZ2},
-		{".bz2", pb.GetArchiveRequest_TAR_BZ2},
+		{"archive", pb.GetArchiveRequest_TAR_GZ},
+		{"master.tar.gz", pb.GetArchiveRequest_TAR_GZ},
+		{"foo-master.tgz", pb.GetArchiveRequest_TAR_GZ},
+		{"foo-v1.2.1.gz", pb.GetArchiveRequest_TAR_GZ},
+		{"foo.tar.bz2", pb.GetArchiveRequest_TAR_BZ2},
+		{"archive.tbz", pb.GetArchiveRequest_TAR_BZ2},
+		{"archive.tbz2", pb.GetArchiveRequest_TAR_BZ2},
+		{"archive.tb2", pb.GetArchiveRequest_TAR_BZ2},
+		{"archive.bz2", pb.GetArchiveRequest_TAR_BZ2},
 	} {
-		basename := "archive" + testCase.in
+		basename := testCase.in
 		out, ok := parseBasename(basename)
 		if !ok {
 			t.Fatalf("parseBasename did not recognize %q", basename)