[Bug]: Port binding not working if breaking the fluent interface

### Testcontainers version

4.12.0

### Using the latest Testcontainers version?

Yes

### Host OS

Windows

### Host arch

x86-64

### .NET version

10.0.300

### Docker version

<details>
<summary>Docker version</summary>

```shell
Client:
 Version:           29.4.3
 API version:       1.54
 Go version:        go1.26.2
 Git commit:        055a478
 Built:             Wed May  6 17:10:36 2026
 OS/Arch:           windows/amd64
 Context:           desktop-linux

Server: Docker Desktop 4.74.0 (227015)
 Engine:
  Version:          29.4.3
  API version:      1.54 (minimum version 1.40)
  Go version:       go1.26.2
  Git commit:       56be731
  Built:            Wed May  6 17:07:37 2026
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v2.2.3
  GitCommit:        77c84241c7cbdd9b4eca2591793e3d4f4317c590
 runc:
  Version:          1.3.5
  GitCommit:        v1.3.5-0-g488fc13e
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0
```

</details>

### Docker info

<details>
<summary>Docker info</summary>

```shell
Client:
 Version:    29.4.3
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  agent: Docker AI Agent Runner (Docker Inc.)
    Version:  v1.57.0
    Path:     C:\Program Files\Docker\cli-plugins\docker-agent.exe
  ai: Docker AI Agent - Ask Gordon (Docker Inc.)
    Version:  v1.20.2
    Path:     C:\Program Files\Docker\cli-plugins\docker-ai.exe
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.33.0-desktop.1
    Path:     C:\Program Files\Docker\cli-plugins\docker-buildx.exe
  compose: Docker Compose (Docker Inc.)
    Version:  v5.1.4
    Path:     C:\Users\gabriele.ricci\.docker\cli-plugins\docker-compose.exe
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.47
    Path:     C:\Program Files\Docker\cli-plugins\docker-debug.exe
  desktop: Docker Desktop commands (Docker Inc.)
    Version:  v0.3.0
    Path:     C:\Program Files\Docker\cli-plugins\docker-desktop.exe
  dhi: CLI for managing Docker Hardened Images (Docker Inc.)
    Version:  v0.0.3
    Path:     C:\Program Files\Docker\cli-plugins\docker-dhi.exe
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.31
    Path:     C:\Program Files\Docker\cli-plugins\docker-extension.exe
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     C:\Program Files\Docker\cli-plugins\docker-init.exe
  mcp: Docker MCP Plugin (Docker Inc.)
    Version:  v0.42.1
    Path:     C:\Program Files\Docker\cli-plugins\docker-mcp.exe
  model: Docker Model Runner (Docker Inc.)
    Version:  v1.1.37
    Path:     C:\Program Files\Docker\cli-plugins\docker-model.exe
  offload: Docker Offload (Docker Inc.)
    Version:  v0.5.89
    Path:     C:\Program Files\Docker\cli-plugins\docker-offload.exe
  pass: Docker Pass Secrets Manager Plugin (beta) (Docker Inc.)
    Version:  v0.0.27
    Path:     C:\Program Files\Docker\cli-plugins\docker-pass.exe
  sandbox: Docker Sandbox (Docker Inc.)
    Version:  v0.12.0
    Path:     C:\Program Files\Docker\cli-plugins\docker-sandbox.exe
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     C:\Program Files\Docker\cli-plugins\docker-sbom.exe
  scout: Docker Scout (Docker Inc.)
    Version:  v1.21.0
    Path:     C:\Users\gabriele.ricci\.docker\cli-plugins\docker-scout.exe


Server:
 Containers: 2
  Running: 2
  Paused: 0
  Stopped: 0
 Images: 17
 Server Version: 29.4.3
 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
 Discovered Devices:
  cdi: docker.com/gpu=webgpu
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 nvidia runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 77c84241c7cbdd9b4eca2591793e3d4f4317c590
 runc version: v1.3.5-0-g488fc13e
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.6.87.2-microsoft-standard-WSL2
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 16
 Total Memory: 15.48GiB
 Name: docker-desktop
 ID: d571f0d6-b9e9-4ae7-86ce-76f0551c1e3d
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=npipe://\\.\pipe\docker_cli
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false
 Firewall Backend: iptables
```

</details>

### What happened?

The port binding is not working if I break the fluent interface like so:
```C#
PostgreSqlBuilder containerBuilder =
    new PostgreSqlBuilder("postgres:15-alpine")
    .WithDatabase(DatabaseName)
    .WithUsername("postgres")
    .WithPassword("Test123!")
    .WithCommand(
        "-c", "fsync=off",
        "-c", "synchronous_commit=off",
        "-c", "full_page_writes=off"
    );

if (Debugger.IsAttached)
{
    containerBuilder.WithPortBinding(55344, 5432);
}

_postgresContainer = containerBuilder.Build();
```

It does work if the call `WithPortBinding` is chained to the fluent interface:
```C#
_postgresContainer = new PostgreSqlBuilder("postgres:15-alpine")
    .WithDatabase(DatabaseName)
    .WithUsername("postgres")
    .WithPassword("Test123!")
    .WithCommand(
        "-c", "fsync=off",
        "-c", "synchronous_commit=off",
        "-c", "full_page_writes=off"
    )
    .WithPortBinding(55344, 5432)
    .Build();
```

Context:
I'm doing some integration testing and I created a class `APIFactory` extending `WebApplicationFactory` and `IAsyncLifetime` to create a base class that is able to call the web service via HTTP mocking it all.
I then use the class `APIFactory` in my test class extending `IClassFixture<APIFactory>`

```C#
public class QualityCheckShould(ApiFactory factory) : IClassFixture<APIFactory>
{
    private readonly HttpClient _client = factory.CreateClient();

    [Fact]
    public async Task MyTest()
    {
        [...]
```

### Relevant log output

```shell

```

### Additional information

_No response_

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[Bug]: Port binding not working if breaking the fluent interface #1692

Testcontainers version

Using the latest Testcontainers version?

Host OS

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[Bug]: Port binding not working if breaking the fluent interface #1692

Description

Testcontainers version

Using the latest Testcontainers version?

Host OS

Host arch

.NET version

Docker version

Docker info

What happened?

Relevant log output

Additional information

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions