fix(upload): hangs indefinitely on download error instead of exiting

internal/api/client.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"strings"
 	"time"
 
 	"github.com/google/uuid"
@@ -308,9 +309,10 @@ func (c *Client) ModelUpload(ctx context.Context, req ModelUploadRequest, opts M
 }
 
 // consumeUploadFrame inspects a single modelUpload pipeline frame. done is
-// true for a terminal frame ("ready" or "failed"). Intermediate statuses are
-// reported through onStatus, deduplicated against *lastStatus so repeated
-// frames for the same phase fire the callback once.
+// true for a terminal frame ("ready", "failed", or other error statuses such as
+// "error downloading"). Intermediate statuses are reported through onStatus,
+// deduplicated against *lastStatus so repeated frames for the same phase fire
+// the callback once.
 func consumeUploadFrame(raw json.RawMessage, onStatus func(status, message string), lastStatus *string) (*ModelUploadResult, bool, error) {
 	var item ModelUploadResult
 	if err := json.Unmarshal(raw, &item); err != nil {
@@ -321,15 +323,12 @@ func consumeUploadFrame(raw json.RawMessage, onStatus func(status, message strin
 	switch item.Status {
 	case uploadStatusReady:
 		return &item, true, nil
-	case uploadStatusFailed:
-		msg := item.Message
-		if msg == "" {
-			msg = "no failure reason reported"
-		}
-		return nil, true, fmt.Errorf("model upload failed: %s", msg)
 	case "":
 		return nil, false, nil
 	default:
+		if msg, failed := uploadFailureMessage(item.Status, item.Message); failed {
+			return nil, true, fmt.Errorf("model upload failed: %s", msg)
+		}
 		if item.Status != *lastStatus {
 			*lastStatus = item.Status
 			if onStatus != nil {
@@ -340,6 +339,21 @@ func consumeUploadFrame(raw json.RawMessage, onStatus func(status, message strin
 	}
 }
 
+// uploadFailureMessage reports whether a modelUpload pipeline status is terminal
+// failure and returns the message to surface to the caller.
+func uploadFailureMessage(status, message string) (string, bool) {
+	if status == uploadStatusFailed || strings.Contains(strings.ToLower(status), "error") {
+		if message != "" {
+			return message, true
+		}
+		if status == uploadStatusFailed {
+			return "no failure reason reported", true
+		}
+		return status, true
+	}
+	return "", false
+}
+
 // Poll polls for async task results using the getResponse task type.
 // It blocks until at least minResults items with status "success" have been
 // returned in a single poll cycle, a data item reports status "error", the

internal/api/types.go

@@ -348,7 +348,7 @@ type ModelUploadRequest struct {
 
 // ModelUploadResult is a single status/result frame from the modelUpload
 // pipeline. Status progresses validated → downloaded → optimized → stored →
-// ready, or failed.
+// ready, or terminates with a failure status such as "failed" or "error downloading".
 type ModelUploadResult struct {
 	TaskType TaskType  `json:"taskType"`
 	TaskUUID uuid.UUID `json:"taskUUID"`

internal/api/upload_test.go

@@ -186,6 +186,43 @@ func TestModelUpload_DuplicateStatusDeduped(t *testing.T) {
 	}
 }
 
+// TestModelUpload_ErrorDownloadingReturnsError: pipeline error statuses such as
+// "error downloading" must terminate the stream instead of waiting indefinitely.
+func TestModelUpload_ErrorDownloadingReturnsError(t *testing.T) {
+	mock := &mockStreamTransport{
+		frames: []json.RawMessage{
+			uploadStatusItem(t, "validated", "", ""),
+			uploadStatusItem(t, "error downloading", "could not fetch file", ""),
+		},
+	}
+
+	_, err := NewClient(mock, slog.Default()).ModelUpload(context.Background(), minimalUploadRequest(), ModelUploadOptions{})
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "could not fetch file") {
+		t.Errorf("expected error to contain failure message, got: %v", err)
+	}
+}
+
+// TestModelUpload_ErrorDownloadingWithoutMessage: when the API omits a message,
+// the status string is used as the failure reason.
+func TestModelUpload_ErrorDownloadingWithoutMessage(t *testing.T) {
+	mock := &mockStreamTransport{
+		frames: []json.RawMessage{
+			uploadStatusItem(t, "error downloading", "", ""),
+		},
+	}
+
+	_, err := NewClient(mock, slog.Default()).ModelUpload(context.Background(), minimalUploadRequest(), ModelUploadOptions{})
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "error downloading") {
+		t.Errorf("expected error to contain status, got: %v", err)
+	}
+}
+
 // TestModelUpload_FailedReturnsError: a "failed" frame surfaces its message.
 func TestModelUpload_FailedReturnsError(t *testing.T) {
 	mock := &mockStreamTransport{