Fixed an issue causing Jar decompression to fail when downloaded using chunked encoding (#124)

Author: djcass44

remote_fetch.go

@@ -75,7 +75,14 @@ func closeBody(resp *http.Response) func() {
 }
 
 func decompressResponse(bodyBytes []byte, contentLength int64, cacheLocator CacheLocator, downloadURL string) error {
-	zipReader, err := zip.NewReader(bytes.NewReader(bodyBytes), contentLength)
+	size := contentLength
+	// if the content length is not set (i.e. chunked encoding),
+	// we need to use the length of the bodyBytes otherwise
+	// the unzip operation will fail
+	if contentLength < 0 {
+		size = int64(len(bodyBytes))
+	}
+	zipReader, err := zip.NewReader(bytes.NewReader(bodyBytes), size)
 	if err != nil {
 		return errorFetchingPostgres(err)
 	}

remote_fetch_test.go

@@ -4,6 +4,8 @@ import (
 	"archive/zip"
 	"crypto/sha256"
 	"encoding/hex"
+	"github.com/stretchr/testify/require"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -370,3 +372,48 @@ func Test_defaultRemoteFetchStrategyWithExistingDownload(t *testing.T) {
 	out2, err := os.ReadFile(cacheLocation)
 	assert.Equal(t, out1, out2)
 }
+
+func Test_defaultRemoteFetchStrategy_whenContentLengthNotSet(t *testing.T) {
+	jarFile, cleanUp := createTempZipArchive()
+	defer cleanUp()
+
+	cacheLocation := filepath.Join(filepath.Dir(jarFile), "extract_location", "cache.jar")
+
+	bytes, err := os.ReadFile(jarFile)
+	if err != nil {
+		require.NoError(t, err)
+	}
+	contentHash := sha256.Sum256(bytes)
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if strings.HasSuffix(r.RequestURI, ".sha256") {
+			w.WriteHeader(200)
+			if _, err := w.Write([]byte(hex.EncodeToString(contentHash[:]))); err != nil {
+				panic(err)
+			}
+
+			return
+		}
+
+		f, err := os.Open(jarFile)
+		if err != nil {
+			panic(err)
+		}
+
+		// stream the file back so that Go uses
+		// chunked encoding and never sets Content-Length
+		_, _ = io.Copy(w, f)
+	}))
+	defer server.Close()
+
+	remoteFetchStrategy := defaultRemoteFetchStrategy(server.URL+"/maven2",
+		testVersionStrategy(),
+		func() (s string, b bool) {
+			return cacheLocation, false
+		})
+
+	err = remoteFetchStrategy()
+
+	assert.NoError(t, err)
+	assert.FileExists(t, cacheLocation)
+}