Make archive validation error messages friendlier (#1188)

* Make archive validation error messages friendlier

* change behaviour a little + fix tests

arduino/resources/checksums.go

@@ -34,6 +34,9 @@ import (
 
 // TestLocalArchiveChecksum test if the checksum of the local archive match the checksum of the DownloadResource
 func (r *DownloadResource) TestLocalArchiveChecksum(downloadDir *paths.Path) (bool, error) {
+	if r.Checksum == "" {
+		return false, fmt.Errorf("missing checksum for: %s", r.ArchiveFileName)
+	}
 	split := strings.SplitN(r.Checksum, ":", 2)
 	if len(split) != 2 {
 		return false, fmt.Errorf("invalid checksum format: %s", r.Checksum)
@@ -69,7 +72,12 @@ func (r *DownloadResource) TestLocalArchiveChecksum(downloadDir *paths.Path) (bo
 	if _, err := io.Copy(algo, file); err != nil {
 		return false, fmt.Errorf("computing hash: %s", err)
 	}
-	return bytes.Compare(algo.Sum(nil), digest) == 0, nil
+
+	if bytes.Compare(algo.Sum(nil), digest) != 0 {
+		return false, fmt.Errorf("archive hash differs from hash in index")
+	}
+
+	return true, nil
 }
 
 // TestLocalArchiveSize test if the local archive size match the DownloadResource size
@@ -82,7 +90,11 @@ func (r *DownloadResource) TestLocalArchiveSize(downloadDir *paths.Path) (bool,
 	if err != nil {
 		return false, fmt.Errorf("getting archive info: %s", err)
 	}
-	return info.Size() == r.Size, nil
+	if info.Size() != r.Size {
+		return false, fmt.Errorf("fetched archive size differs from size specified in index")
+	}
+
+	return true, nil
 }
 
 // TestLocalArchiveIntegrity checks for integrity of the local archive.
@@ -94,7 +106,7 @@ func (r *DownloadResource) TestLocalArchiveIntegrity(downloadDir *paths.Path) (b
 	}
 
 	if ok, err := r.TestLocalArchiveSize(downloadDir); err != nil {
-		return false, fmt.Errorf("teting archive size: %s", err)
+		return false, fmt.Errorf("testing archive size: %s", err)
 	} else if !ok {
 		return false, nil
 	}
@@ -163,5 +175,9 @@ func CheckDirChecksum(root string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	return file.Checksum == checksum, nil
+	if file.Checksum != checksum {
+		return false, fmt.Errorf("Checksum differs from checksum in package.json")
+	}
+
+	return true, nil
 }

arduino/resources/helpers.go

@@ -44,26 +44,23 @@ func (r *DownloadResource) IsCached(downloadDir *paths.Path) (bool, error) {
 
 // Download a DownloadResource.
 func (r *DownloadResource) Download(downloadDir *paths.Path, config *downloader.Config) (*downloader.Downloader, error) {
-	cached, err := r.TestLocalArchiveIntegrity(downloadDir)
-	if err != nil {
-		return nil, fmt.Errorf("testing local archive integrity: %s", err)
-	}
-	if cached {
-		// File is cached, nothing to do here
-		return nil, nil
-	}
-
 	path, err := r.ArchivePath(downloadDir)
 	if err != nil {
 		return nil, fmt.Errorf("getting archive path: %s", err)
 	}
 
-	if stats, err := path.Stat(); os.IsNotExist(err) {
+	if _, err := path.Stat(); os.IsNotExist(err) {
 		// normal download
-	} else if err == nil && stats.Size() > r.Size {
-		// file is bigger than expected, retry download...
-		if err := path.Remove(); err != nil {
-			return nil, fmt.Errorf("removing corrupted archive file: %s", err)
+	} else if err == nil {
+		// check local file integrity
+		ok, err := r.TestLocalArchiveIntegrity(downloadDir)
+		if err != nil || !ok {
+			if err := path.Remove(); err != nil {
+				return nil, fmt.Errorf("removing corrupted archive file: %s", err)
+			}
+		} else {
+			// File is cached, nothing to do here
+			return nil, nil
 		}
 	} else if err == nil {
 		// resume download

arduino/resources/resources_test.go

@@ -26,19 +26,21 @@ import (
 )
 
 func TestDownloadAndChecksums(t *testing.T) {
+	testFileName := "core.zip"
 	tmp, err := paths.MkTempDir("", "")
 	require.NoError(t, err)
 	defer tmp.RemoveAll()
-	testFile := tmp.Join("cache", "index.html")
+	testFile := tmp.Join("cache", testFileName)
 
+	// taken from test/testdata/test_index.json
 	r := &DownloadResource{
-		ArchiveFileName: "index.html",
+		ArchiveFileName: testFileName,
 		CachePath:       "cache",
-		Checksum:        "SHA-256:e021e1a223d03069d5f08dea25a58ca445a7376d9bdf980f756034f118449e66",
-		Size:            1119,
-		URL:             "https://downloads.arduino.cc/index.html",
+		Checksum:        "SHA-256:6a338cf4d6d501176a2d352c87a8d72ac7488b8c5b82cdf2a4e2cef630391092",
+		Size:            486,
+		URL:             "https://raw.githubusercontent.com/arduino/arduino-cli/master/test/testdata/core.zip",
 	}
-	digest, err := hex.DecodeString("e021e1a223d03069d5f08dea25a58ca445a7376d9bdf980f756034f118449e66")
+	digest, err := hex.DecodeString("6a338cf4d6d501176a2d352c87a8d72ac7488b8c5b82cdf2a4e2cef630391092")
 	require.NoError(t, err)
 
 	downloadAndTestChecksum := func() {
@@ -73,10 +75,14 @@ func TestDownloadAndChecksums(t *testing.T) {
 	// Download if cached file has less data (resume)
 	data, err = testFile.ReadFile()
 	require.NoError(t, err)
-	err = testFile.WriteFile(data[:1000])
+	err = testFile.WriteFile(data[:100])
 	require.NoError(t, err)
 	downloadAndTestChecksum()
 
+	r.Checksum = ""
+	_, err = r.TestLocalArchiveChecksum(tmp)
+	require.Error(t, err)
+
 	r.Checksum = "BOH:12312312312313123123123123123123"
 	_, err = r.TestLocalArchiveChecksum(tmp)
 	require.Error(t, err)
@@ -89,21 +95,16 @@ func TestDownloadAndChecksums(t *testing.T) {
 	_, err = r.TestLocalArchiveChecksum(tmp)
 	require.Error(t, err)
 
-	r.Checksum = "SHA-1:c007e47637cc6ad6176e7d94aeffc232ee34c1c1"
+	r.Checksum = "SHA-1:16e1495aff482f2650733e1661d5f7c69040ec13"
 	res, err := r.TestLocalArchiveChecksum(tmp)
 	require.NoError(t, err)
 	require.True(t, res)
 
-	r.Checksum = "MD5:2e388576eefd92a15967868d5f566f29"
+	r.Checksum = "MD5:3bcc3aab6842ff124df6a5cfba678ca1"
 	res, err = r.TestLocalArchiveChecksum(tmp)
 	require.NoError(t, err)
 	require.True(t, res)
 
-	r.Checksum = "MD5:12312312312312312312313131231231"
-	res, err = r.TestLocalArchiveChecksum(tmp)
-	require.NoError(t, err)
-	require.False(t, res)
-
 	_, err = r.TestLocalArchiveChecksum(paths.New("/not-existent"))
 	require.Error(t, err)