[Bug]: When only using `credsStore` auth isn't used for any registry

[hammypants]

Testcontainers version

0.40 and 0.41

Using the latest Testcontainers version?

Yes

Host OS

Linux, MacOS

Host arch

x86, ARM

Go version

1.26

Docker version

All of them would be a lot (CI/CD-- all 29.*) but here's dev machine stuff:

 Version:           29.2.1
 API version:       1.53
 Go version:        go1.25.6
 Git commit:        a5c7197d72
 Built:             Mon Feb  2 16:33:58 2026
 OS/Arch:           darwin/arm64
 Context:           default

Docker info

Client: Docker Engine - Community
 Version:    29.2.1
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.31.1
    Path:     /<redacted>/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  5.0.2
    Path:     /<redacted>/.docker/cli-plugins/docker-compose

Server:
 Containers: 32
  Running: 19
  Paused: 0
  Stopped: 13
 Images: 21
 Server Version: 29.2.0
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: dea7da592f5d1d2b7755e3a161be07f43fad8f75
 runc version: v1.3.4-0-gd6d73eb8
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.8.0-90-generic
 Operating System: Ubuntu 24.04.3 LTS
 OSType: linux
 Architecture: aarch64
 CPUs: 4
 Total Memory: 7.737GiB
 Name: colima
 ID: <redacted>
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false
 Firewall Backend: iptables

What happened?

When only using (no auths, credshelpers, etc)

{
  "credsStore": "ecr-login"
}

(use credsStore for all registries)

testcontainers-go doesn't auth any registry.

Relevant log output

Error:      	Received unexpected error:
        	            	run postgres: generic container: create container: Error response from daemon: Head "<redacted>": no basic auth credentials

Additional information

Not requiring authentication for the registry, everything works. We discovered this when moving to a proxied image cache. We're doing this for a slew of languages and frameworks using testcontainers. Go is the only one where we've had an issue.

It also looks like in #1078 the decision was made to always check credsHelpers, but this is incorrect now. credsStore should be enough to configure all registries.