deps: bump go-tail to fix duplicates and stalls

CHANGELOG.md

@@ -130,12 +130,18 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   backup take a cluster-wide recovery point.
 - `tt backup`: remove `creation_duration` from the cluster manifest — the
   field was unused and is no longer serialized.
+- `tt log -f` / `tt tcm log --follow`: only complete lines are printed. A
+  half-written line stays buffered until its newline arrives instead of
+  being split into two records.
 
 ### Fixed
 
 - `tt log -f`: possible line loss/duplication on rename, hanging after
   a watched log directory is removed, and lines written just as the
   file was read to the end not showing up until the next write.
+- `tt log -f` / `tt tcm log --follow`: a line could be delivered twice
+  right after a log rotation, and the follow could stall, never picking
+  up the rotated file (go-tail v1.4.15).
 
 ## [2.13.0] - 2026-05-21
 

cli/tail/follow.go

@@ -86,16 +86,18 @@ func (f *fileFollower) tryReopenTailer(ctx context.Context, cfg *tail.Config) (*
 	}
 
 	for i := range maxRetriesReopen {
-		timer := time.NewTimer(retryOpenDelay)
-		defer timer.Stop()
+		if i > 0 {
+			timer := time.NewTimer(retryOpenDelay)
 
-		select {
-		case <-ctx.Done():
-			return nil, fmt.Errorf("context (%w) while waiting to retry for %q",
-				ctx.Err(), f.name)
+			select {
+			case <-ctx.Done():
+				timer.Stop()
+				return nil, fmt.Errorf("context (%w) while waiting to retry for %q",
+					ctx.Err(), f.name)
 
-		case <-timer.C:
-			log.Infof("Wake up to retry tailing %q", f.name)
+			case <-timer.C:
+				log.Infof("Wake up to retry tailing %q", f.name)
+			}
 		}
 
 		newT, err := tail.TailFile(f.name, newCfg)
@@ -139,7 +141,11 @@ func (f *fileFollower) handleTailerStopStatus(ctx context.Context, curT *tail.Ta
 		return t, nil
 	}
 
-	return nil, fmt.Errorf("failed to stop tailer for %q: %w", f.name, stopErr)
+	if stopErr != nil {
+		return nil, fmt.Errorf("failed to stop tailer for %q: %w", f.name, stopErr)
+	}
+
+	return nil, fmt.Errorf("tailer for %q stopped unexpectedly", f.name)
 }
 
 func (f *fileFollower) followFile(ctx context.Context, t *tail.Tail, out chan<- string) {
@@ -223,7 +229,12 @@ func (f *fileFollower) startFollowing(ctx context.Context, out chan<- string, li
 		MustExist: true,
 		Follow:    true,
 		ReOpen:    true,
-		Logger:    tail.DiscardingLogger,
+		// Half-written lines stay buffered until their newline arrives:
+		// yielding them early would split a log record in two, and the
+		// seek-to-end after an early yield can skip bytes appended in
+		// the meantime.
+		CompleteLines: true,
+		Logger:        tail.DiscardingLogger,
 	}
 
 	t, err := tail.TailFile(f.name, tCfg)

cli/tail/tail.go

@@ -191,10 +191,14 @@ func Follow(ctx context.Context, out chan<- string, logFormatter LogFormatter, f
 			Offset: startPos,
 			Whence: io.SeekStart,
 		},
-		MustExist:     true,
-		Follow:        true,
-		ReOpen:        true,
-		CompleteLines: false,
+		MustExist: true,
+		Follow:    true,
+		ReOpen:    true,
+		// Half-written lines stay buffered until their newline arrives:
+		// yielding them early would split a log record in two, and the
+		// seek-to-end after an early yield can skip bytes appended in
+		// the meantime.
+		CompleteLines: true,
 		Logger:        tail.DiscardingLogger,
 	})
 	if err != nil {
@@ -217,7 +221,8 @@ func Follow(ctx context.Context, out chan<- string, logFormatter LogFormatter, f
 					if err != nil {
 						log.Error(err.Error())
 					} else {
-						log.Errorf("The log file %q is unavailable for reading. Exiting.")
+						log.Errorf("The log file %q is unavailable for reading. Exiting.",
+							t.Filename)
 					}
 					return
 				}

go.mod

@@ -32,7 +32,7 @@ require (
 	github.com/tarantool/go-iproto v1.1.0
 	github.com/tarantool/go-prompt v1.0.1
 	github.com/tarantool/go-storage v1.5.0
-	github.com/tarantool/go-tail v1.4.14
+	github.com/tarantool/go-tail v1.4.15-0.20260806154205-254b9b0cd094
 	github.com/tarantool/go-tarantool v1.12.3
 	github.com/tarantool/go-tarantool/v2 v2.4.2
 	github.com/tarantool/go-xlog v0.0.0-20260707203858-fed522934686

go.sum

@@ -360,8 +360,8 @@ github.com/tarantool/go-prompt v1.0.1 h1:88Yer6gCFylqGRrdWwikNFVbklRQsqKF7mycvGd
 github.com/tarantool/go-prompt v1.0.1/go.mod h1:9Vuvi60Bk+3yaXqgYaXNTpLbwPPaaEOeaUgpFW1jqTU=
 github.com/tarantool/go-storage v1.5.0 h1:WRi5eahOinBHh+Nnc5CmiaFNxYQCd5OoiUfA7n9pe30=
 github.com/tarantool/go-storage v1.5.0/go.mod h1:Aj8RoWXZGYOI7oWT3Utj9IE7FItvMSDf2smHxHJo96M=
-github.com/tarantool/go-tail v1.4.14 h1:myfx/k3Xf9N7RPq/0qyuZw5jqqNb2lrheLdaBHyQUT8=
-github.com/tarantool/go-tail v1.4.14/go.mod h1:NqLWssaRJ2w9myxdJWlc4WaZWHU2CLZDdEYfKlSnbEQ=
+github.com/tarantool/go-tail v1.4.15-0.20260806154205-254b9b0cd094 h1:uNFHojM8qO8yBwy4FFdrjFDvcztK4v1ucvPaEpPFaEw=
+github.com/tarantool/go-tail v1.4.15-0.20260806154205-254b9b0cd094/go.mod h1:7OEbsSv1hZ/XfBlgeglrMry5GUeJS3be9SoGLxbA1fo=
 github.com/tarantool/go-tarantool v1.12.3 h1:GXabowmrTSW225xFEjX4t+8PlccVDCeGB5OM1VLbBXE=
 github.com/tarantool/go-tarantool v1.12.3/go.mod h1:QRiXv0jnxwgxHtr9ZmifSr/eRba76gTUBgp69pDMX1U=
 github.com/tarantool/go-tarantool/v2 v2.4.2 h1:rkzYtFhLJLA9RDIhjzN93MJBN5PBxHW4+soq+RB90gE=

test/integration/tcm/test_tcm_log.py

@@ -254,10 +254,7 @@ def test_log_rotate(
     tmp_log.rename(tmp_log.with_suffix(".bak"))
     assert not tmp_log.exists(), "Temporary log file should be deleted."
 
-    # Create the replacement separately so the asynchronous reopen path can
-    # attach its watcher before new records are written.
     tmp_log.touch()
-    time.sleep(0.5)
 
     new_lines, cnt_lines = handle_updating_logs(reader, tmp_log, mode, delay_time, is_append=True)
     stdout_lines.extend(new_lines)