stray empty line printed when running `--call` with `--quiet`

[thaJeztah]

Contributing guidelines

• I've read the contributing guidelines and wholeheartedly agree

I've found a bug and checked that ...

• ... the documentation does not mention anything about my problem
• ... there are no open or closed issues that are related to my problem

Description

I noticed a small difference in output between --progress=none and --quiet; when using --quiet, a stray empty line is printed;

docker build -q --call=outline .

BUILD ARG        VALUE                                     DESCRIPTION
GO_VERSION       1.23.7
ALPINE_VERSION   3.21
XX_VERSION       1.9.0                                     version of the tonistiigi/xx utility to use.
PKG              github.com/distribution/distribution/v3
LDFLAGS          -s -w
BUILDTAGS


What's next:
    View a summary of image vulnerabilities and recommendations → docker scout quickview

Whereas with --progress=none, that's not the case;

docker build --progress=none --call=outline .
BUILD ARG        VALUE                                     DESCRIPTION
GO_VERSION       1.23.7
ALPINE_VERSION   3.21
XX_VERSION       1.9.0                                     version of the tonistiigi/xx utility to use.
PKG              github.com/distribution/distribution/v3
LDFLAGS          -s -w
BUILDTAGS


What's next:
    View a summary of image vulnerabilities and recommendations → docker scout quickview

Expected behaviour

Same output (no empty line)

Actual behaviour

Empty line

Buildx version

docker buildx version github.com/docker/buildx v0.31.1-desktop.1 3d153e82f8d99923062781d390607dabe1679613

Docker info

Client:
 Version:           29.2.1
 API version:       1.53
 Go version:        go1.25.6
 Git commit:        a5c7197
 Built:             Mon Feb  2 17:16:37 2026
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.61.0 (218081)
 Engine:
  Version:          29.2.1
  API version:      1.53 (minimum version 1.44)
  Go version:       go1.25.6
  Git commit:       6bc6209
  Built:            Mon Feb  2 17:16:47 2026
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          v2.2.1
  GitCommit:        dea7da592f5d1d2b7755e3a161be07f43fad8f75
 runc:
  Version:          1.3.4
  GitCommit:        v1.3.4-0-gd6d73eb8
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Builders list

not relevant

Configuration

not relevant

Build logs

Additional info

No response