Multi-machine sync correctness: transcript conflicts, history merge, debris, desktop records

cmd/claude-sync/main.go

@@ -1010,6 +1010,18 @@ func runWebDAVWizard(webdavURL, username, password, pathPrefix string) (*storage
 	return cfg, nil
 }
 
+// reportQuietErrors prints per-file sync errors to stderr in quiet mode.
+// Session hooks run with -q, which suppresses all normal output — but a
+// failure must never be invisible.
+func reportQuietErrors(result *sync.SyncResult) {
+	if !quiet || result == nil {
+		return
+	}
+	for _, e := range result.Errors {
+		fmt.Fprintf(os.Stderr, "claude-sync: %v\n", e)
+	}
+}
+
 func pushCmd() *cobra.Command {
 	var includeMCP bool
 
@@ -1072,6 +1084,8 @@ func pushCmd() *cobra.Command {
 				return err
 			}
 
+			reportQuietErrors(result)
+
 			if !quiet {
 				fmt.Println() // Clear the progress line
 
@@ -1201,6 +1215,8 @@ Examples:
 				return err
 			}
 
+			reportQuietErrors(result)
+
 			if !quiet {
 				fmt.Println() // Clear the progress line
 

internal/storage/gcs/gcs.go

@@ -160,6 +160,9 @@ func (c *Client) List(ctx context.Context, prefix string) ([]appstorage.ObjectIn
 func (c *Client) Head(ctx context.Context, key string) (*appstorage.ObjectInfo, error) {
 	attrs, err := c.client.Bucket(c.bucket).Object(key).Attrs(ctx)
 	if err != nil {
+		if errors.Is(err, storage.ErrObjectNotExist) {
+			return nil, fmt.Errorf("%s: %w", key, appstorage.ErrNotFound)
+		}
 		return nil, err
 	}
 

internal/storage/r2/r2.go

@@ -186,6 +186,10 @@ func (c *Client) Head(ctx context.Context, key string) (*storage.ObjectInfo, err
 		Key:    aws.String(key),
 	})
 	if err != nil {
+		var notFound *types.NotFound
+		if errors.As(err, &notFound) {
+			return nil, fmt.Errorf("%s: %w", key, storage.ErrNotFound)
+		}
 		return nil, err
 	}
 

internal/storage/s3/s3.go

@@ -200,6 +200,10 @@ func (c *Client) Head(ctx context.Context, key string) (*storage.ObjectInfo, err
 		Key:    aws.String(key),
 	})
 	if err != nil {
+		var notFound *types.NotFound
+		if errors.As(err, &notFound) {
+			return nil, fmt.Errorf("%s: %w", key, storage.ErrNotFound)
+		}
 		return nil, err
 	}
 

internal/storage/storage.go

@@ -2,10 +2,23 @@ package storage
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 )
 
+// ErrNotFound distinguishes a missing object from transient failures
+// (timeouts, throttling, 5xx). Adapters wrap their provider-specific
+// not-found errors with it; callers that must not confuse "absent" with
+// "unreachable" — such as the history merge-on-push, where the difference is
+// clobbering the bucket union — check it via IsNotFound.
+var ErrNotFound = errors.New("object not found")
+
+// IsNotFound reports whether err indicates the object does not exist.
+func IsNotFound(err error) bool {
+	return errors.Is(err, ErrNotFound)
+}
+
 // Provider represents a storage provider type
 type Provider string
 

internal/storage/webdav/webdav.go

@@ -365,7 +365,7 @@ func (c *Client) Head(ctx context.Context, key string) (*storage.ObjectInfo, err
 	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode == http.StatusNotFound {
-		return nil, fmt.Errorf("object not found: %s", key)
+		return nil, fmt.Errorf("%s: %w", key, storage.ErrNotFound)
 	}
 
 	if resp.StatusCode != 207 {