Use longest suffix match to pick up checksum

http/compression.go

@@ -47,15 +47,21 @@ func DownloadTryCompression(downloader aptly.Downloader, url string, expectedChe
 		tryURL := url + method.extenstion
 		foundChecksum := false
 
-		for suffix, expected := range expectedChecksums {
+		bestSuffix := ""
+
+		for suffix := range expectedChecksums {
 			if strings.HasSuffix(tryURL, suffix) {
-				file, err = DownloadTempWithChecksum(downloader, tryURL, &expected, ignoreMismatch, maxTries)
 				foundChecksum = true
-				break
+				if len(suffix) > len(bestSuffix) {
+					bestSuffix = suffix
+				}
 			}
 		}
 
-		if !foundChecksum {
+		if foundChecksum {
+			expected := expectedChecksums[bestSuffix]
+			file, err = DownloadTempWithChecksum(downloader, tryURL, &expected, ignoreMismatch, maxTries)
+		} else {
 			if !ignoreMismatch {
 				continue
 			}

http/compression_test.go

@@ -89,6 +89,27 @@ func (s *CompressionSuite) TestDownloadTryCompression(c *C) {
 	c.Assert(d.Empty(), Equals, true)
 }
 
+func (s *CompressionSuite) TestDownloadTryCompressionLongestSuffix(c *C) {
+	var buf []byte
+
+	expectedChecksums := map[string]utils.ChecksumInfo{
+		"file.bz2":          {Size: 1},
+		"subdir/file.bz2":   {Size: int64(len(bzipData))},
+		"otherdir/file.bz2": {Size: 1},
+	}
+
+	// longest suffix should be picked up
+	buf = make([]byte, 4)
+	d := NewFakeDownloader()
+	d.ExpectResponse("http://example.com/subdir/file.bz2", bzipData)
+	r, file, err := DownloadTryCompression(d, "http://example.com/subdir/file", expectedChecksums, false, 1)
+	c.Assert(err, IsNil)
+	defer file.Close()
+	io.ReadFull(r, buf)
+	c.Assert(string(buf), Equals, rawData)
+	c.Assert(d.Empty(), Equals, true)
+}
+
 func (s *CompressionSuite) TestDownloadTryCompressionErrors(c *C) {
 	d := NewFakeDownloader()
 	_, _, err := DownloadTryCompression(d, "http://example.com/file", nil, true, 1)