fix(config): warn when service selection is silently ignored

`docker compose config --no-interpolate <service>` and
`docker compose config --variables <service>` load the raw model
without applying service filtering, so the full model is rendered
regardless of the services passed as arguments. Filtering will not
be supported on these paths, so emit a warning to make sure users
are no longer misled by silently ignored arguments.

Fixes #13614

Signed-off-by: Guillaume Lours <glours@users.noreply.github.com>

cmd/compose/config.go

@@ -32,6 +32,7 @@ import (
 	"github.com/compose-spec/compose-go/v2/template"
 	"github.com/compose-spec/compose-go/v2/types"
 	"github.com/docker/cli/cli/command"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"go.yaml.in/yaml/v4"
 
@@ -266,6 +267,9 @@ func imagesOnly(project *types.Project) *types.Project {
 }
 
 func runConfigNoInterpolate(ctx context.Context, dockerCli command.Cli, opts configOptions, services []string) ([]byte, error) {
+	if len(services) > 0 {
+		logrus.Warn("service filtering is not applied when --no-interpolate is set, the full model will be rendered")
+	}
 	// we can't use ToProject, so the model we render here is only partially resolved
 	model, err := opts.ToModel(ctx, dockerCli, services)
 	if err != nil {
@@ -519,6 +523,9 @@ func runConfigImages(ctx context.Context, dockerCli command.Cli, opts configOpti
 }
 
 func runVariables(ctx context.Context, dockerCli command.Cli, opts configOptions, services []string) error {
+	if len(services) > 0 {
+		logrus.Warn("service filtering is not applied when --variables is set, variables from the full model will be rendered")
+	}
 	opts.noInterpolate = true
 	model, err := opts.ToModel(ctx, dockerCli, services, cli.WithoutEnvironmentResolution, cli.WithLoadOptions(loader.WithSkipValidation))
 	if err != nil {

pkg/e2e/config_test.go

@@ -47,6 +47,14 @@ func TestLocalComposeConfig(t *testing.T) {
 		res.Assert(t, icmd.Expected{Out: `- ${PORT:-8080}:80`})
 	})
 
+	t.Run("--no-interpolate with service selection", func(t *testing.T) {
+		res := c.RunDockerComposeCmd(t, "-f", "./fixtures/config/compose.yaml", "--project-name", projectName, "config", "--no-interpolate", "test")
+		res.Assert(t, icmd.Expected{
+			Err: "service filtering is not applied when --no-interpolate is set",
+			Out: `- ${PORT:-8080}:80`,
+		})
+	})
+
 	t.Run("--variables --format json", func(t *testing.T) {
 		res := c.RunDockerComposeCmd(t, "-f", "./fixtures/config/compose.yaml", "--project-name", projectName, "config", "--variables", "--format", "json")
 		res.Assert(t, icmd.Expected{Out: `{
@@ -67,4 +75,12 @@ func TestLocalComposeConfig(t *testing.T) {
     presencevalue: ""
     required: false`})
 	})
+
+	t.Run("--variables with service selection", func(t *testing.T) {
+		res := c.RunDockerComposeCmd(t, "-f", "./fixtures/config/compose.yaml", "--project-name", projectName, "config", "--variables", "test")
+		res.Assert(t, icmd.Expected{
+			Err: "service filtering is not applied when --variables is set",
+			Out: `PORT`,
+		})
+	})
 }