compose: RenderEntrypointWrapper doesn't gate entrypoint/command on overrideCommand

[bilby91]

Summary

compose.RenderEntrypointWrapper (added in #103) is a faithful port of the reference devcontainers/cli generateFeaturesComposeOverrideContent, with one deliberate gap: it does not implement overrideCommand gating of the original entrypoint/command.

Reference behavior

In src/spec-node/dockerCompose.ts the CLI computes:

const userEntrypoint = overrideCommand ? [] : composeEntrypoint || (imageEntrypoint…);
const userCommand    = overrideCommand ? [] : composeCommand   || (imageCmd…);
// …emits `command: <userCommand>` only when userCommand !== composeCommand

When overrideCommand is true, both the original entrypoint and command are zeroed — the generated wrapper runs the feature entrypoints, then exec "$@" hits empty args and falls through to the while sleep 1 & wait $!; do :; done keep-alive.

Our behavior

RenderEntrypointWrapper always preserves the original entrypoint (service's entrypoint:, else the image ENTRYPOINT) and never zeroes the command or emits a command: override. We do not read cfg.OverrideCommand on the compose path at all (serviceToRunSpec also ignores it).

Why this is low priority

Per the dev container spec, overrideCommand defaults to false for Docker Compose (true only for image/Dockerfile). With it false, the reference takes the composeEntrypoint || … / composeCommand || … branches — i.e. preserves exactly what we preserve. So for the default compose case (and the DAP devcontainer this was built for), our output is behaviorally equivalent to upstream.

The only divergence is an explicit "overrideCommand": true on a compose devcontainer: upstream would drop the service command and rely on the wrapper's keep-alive; we keep the command.

Options

• Implement overrideCommand gating in the compose path for full parity (zero entrypoint/command + emit keep-alive command when overrideCommand is true), or
• Leave as-is and document the limitation.

Related

• PR compose: apply feature security metadata + entrypoint chaining to services #103 (compose feature security metadata + entrypoint chaining)
• Separate follow-up: image-source (non-compose) entrypoint chaining is also not yet implemented (newRunSpec doesn't consume cfg.Entrypoints).