More tests and human review

s3/client_multipart.go

@@ -71,7 +71,7 @@ func (c *Client) listMultipartUploads(ctx context.Context) ([]*multipartUpload,
 		keyMarker = result.NextKeyMarker
 		uploadIDMarker = result.NextUploadIDMarker
 	}
-	return nil, fmt.Errorf("s3: listMultipartUploads exceeded %d pages", maxPages)
+	return nil, fmt.Errorf("error listing multipart uploads, exceeded %d pages", maxPages)
 }
 
 // abortMultipartUpload cancels an in-progress multipart upload. Called on error to clean up.
@@ -122,10 +122,9 @@ func (c *Client) putObjectMultipart(ctx context.Context, key string, body io.Rea
 		}
 		if err == io.EOF || errors.Is(err, io.ErrUnexpectedEOF) {
 			break
-		}
-		if err != nil {
+		} else if err != nil {
 			c.abortMultipartUpload(ctx, key, uploadID)
-			return fmt.Errorf("s3: PutObject read: %w", err)
+			return fmt.Errorf("error uploading object %s, reading from client failed: %w", key, err)
 		}
 	}
 
@@ -172,7 +171,7 @@ func (c *Client) completeMultipartUpload(ctx context.Context, key, uploadID stri
 	log.Tag(tagS3Client).Debug("Completing multipart upload for object %s, %d parts", key, len(parts))
 	bodyBytes, err := xml.Marshal(&completeMultipartUploadRequest{Parts: parts})
 	if err != nil {
-		return fmt.Errorf("s3: CompleteMultipartUpload marshal: %w", err)
+		return fmt.Errorf("error marshalling complete multipart upload request: %w", err)
 	}
 	reqURL := fmt.Sprintf("%s?uploadId=%s", c.config.ObjectURL(key), url.QueryEscape(uploadID))
 	respBody, err := c.do(ctx, "CompleteMultipartUpload", http.MethodPost, reqURL, bodyBytes, nil)
@@ -180,7 +179,7 @@ func (c *Client) completeMultipartUpload(ctx context.Context, key, uploadID stri
 		return err
 	}
 	// Check if the response contains an error (S3 can return 200 with an error body)
-	var errResp ErrorResponse
+	var errResp errorResponse
 	if xml.Unmarshal(respBody, &errResp) == nil && errResp.Code != "" {
 		return &errResp
 	}

s3/client_test.go

@@ -456,7 +456,7 @@ func TestClient_GetObject_NotFound(t *testing.T) {
 
 	_, _, err := client.GetObject(context.Background(), "nonexistent")
 	require.Error(t, err)
-	var errResp *ErrorResponse
+	var errResp *errorResponse
 	require.ErrorAs(t, err, &errResp)
 	require.Equal(t, 404, errResp.StatusCode)
 	require.Equal(t, "NoSuchKey", errResp.Code)
@@ -799,7 +799,7 @@ func TestClient_RealBucket(t *testing.T) {
 		// Get after delete should fail
 		_, _, err = client.GetObject(ctx, key)
 		require.Error(t, err)
-		var errResp *ErrorResponse
+		var errResp *errorResponse
 		require.ErrorAs(t, err, &errResp)
 		require.Equal(t, 404, errResp.StatusCode)
 	})

s3/types.go

@@ -76,15 +76,15 @@ type Object struct {
 	LastModified time.Time
 }
 
-// ErrorResponse is returned when S3 responds with a non-2xx status code.
-type ErrorResponse struct {
+// errorResponse is returned when S3 responds with a non-2xx status code.
+type errorResponse struct {
 	StatusCode int
 	Code       string `xml:"Code"`
 	Message    string `xml:"Message"`
 	Body       string `xml:"-"` // raw response body
 }
 
-func (e *ErrorResponse) Error() string {
+func (e *errorResponse) Error() string {
 	if e.Code != "" {
 		return fmt.Sprintf("s3: %s (HTTP %d): %s", e.Code, e.StatusCode, e.Message)
 	}

s3/util.go

@@ -84,7 +84,7 @@ func ParseURL(s3URL string) (*Config, error) {
 	}, nil
 }
 
-// parseError reads an S3 error response and returns an *ErrorResponse.
+// parseError reads an S3 error response and returns an *errorResponse.
 func parseError(resp *http.Response) error {
 	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseBytes))
 	if err != nil {
@@ -94,7 +94,7 @@ func parseError(resp *http.Response) error {
 }
 
 func parseErrorFromBytes(statusCode int, body []byte) error {
-	errResp := &ErrorResponse{
+	errResp := &errorResponse{
 		StatusCode: statusCode,
 		Body:       string(body),
 	}

s3/util_test.go

@@ -163,7 +163,7 @@ func TestParseError_XMLResponse(t *testing.T) {
 	xmlBody := []byte(`<?xml version="1.0" encoding="UTF-8"?><Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message></Error>`)
 	err := parseErrorFromBytes(404, xmlBody)
 
-	var errResp *ErrorResponse
+	var errResp *errorResponse
 	require.ErrorAs(t, err, &errResp)
 	require.Equal(t, 404, errResp.StatusCode)
 	require.Equal(t, "NoSuchKey", errResp.Code)
@@ -173,7 +173,7 @@ func TestParseError_XMLResponse(t *testing.T) {
 func TestParseError_NonXMLResponse(t *testing.T) {
 	err := parseErrorFromBytes(500, []byte("internal server error"))
 
-	var errResp *ErrorResponse
+	var errResp *errorResponse
 	require.ErrorAs(t, err, &errResp)
 	require.Equal(t, 500, errResp.StatusCode)
 	require.Equal(t, "", errResp.Code) // XML parsing failed, no code