init/new: generated devcontainer postCreateCommand fails on Podman-on-Windows (missing `file`, unguarded chmod)

[kaspergff]

Summary

The devcontainer generated by mxcli init / mxcli new (template in cmd/mxcli/tool_templates.go) has two independent bugs in its postCreateCommand that make the container's post-create step fail (VS Code shows a red error) when the workspace is a bind-mount from a Windows drive under Podman.

The container itself builds and works — mxcli runs fine, the binary is -rwxrwxrwx and executable — but postCreateCommand exits non-zero, so VS Code marks the whole setup as failed.

Environment

• Windows 11 + WSL2 + Podman 5.8.2
• Devcontainer for a Mendix project on C:\Mendix\...
• Workspace bind-mounted via 9p into the Podman machine (/mnt/c), then into the container
• Base image: mcr.microsoft.com/devcontainers/base:bookworm
• mxcli v0.14.0

Symptoms (from the container log)

command not found: file
chmod: changing permissions of './mxcli': Operation not permitted

Bug 1 — file is not installed in the image

postCreateCommand runs:

if [ -f ./mxcli ] && file ./mxcli | grep -q Linux; then echo 'mxcli binary OK'; else ...download...; fi

But the Dockerfile's apt install list (cmd/mxcli/tool_templates.go, the generateDockerfile main apt-get install) is:

wget apt-transport-https gpg ca-certificates curl temurin-21-jdk nodejs postgresql-client kafkacat

There is no file. So file ./mxcli emits command not found, the pipeline fails, the fast-path (mxcli binary OK) is never taken, and the command always falls through to the download branch even when a valid Linux binary is already committed. Wasteful, and it sets up Bug 2.

Fix: add file to the Dockerfile apt install list so the Linux-binary check works as intended.

Bug 2 — unguarded chmod +x ./mxcli fails on a 9p bind-mount

The download fallback branch ends with:

curl -fsSL .../mxcli-linux-${ARCH} -o ./mxcli && chmod +x ./mxcli

On a 9p filesystem (Windows drive bind-mounted through the Podman machine), Unix permission changes are not permitted, so chmod fails with Operation not permitted. The binary is already executable (9p exposes it -rwxrwxrwx), so the chmod is unnecessary — but its non-zero exit propagates and fails the entire postCreateCommand.

Fix: guard the chmod so it can't fail the step:

chmod +x ./mxcli 2>/dev/null || true

Proposed diff

cmd/mxcli/tool_templates.go:

postCreateCommand — guard the chmod:

-... && curl -fsSL https://github.com/mendixlabs/mxcli/releases/latest/download/mxcli-linux-${ARCH} -o ./mxcli && chmod +x ./mxcli; }; fi
+... && curl -fsSL https://github.com/mendixlabs/mxcli/releases/latest/download/mxcli-linux-${ARCH} -o ./mxcli && { chmod +x ./mxcli 2>/dev/null || true; }; }; fi

Dockerfile apt list — install file:

     apt-get install -y --no-install-recommends \
        temurin-21-jdk \
        nodejs \
        postgresql-client \
+       file \
        kafkacat \

Both fixes are independent; together they make mxcli init/new devcontainers work cleanly on Podman-on-Windows with a Windows-drive workspace.

Related

• Follow-up enhancement: publish a prebuilt devcontainer image to ghcr.io to avoid the ~5min local build (separate issue).
• init generates devcontainer.json referencing non-existent feature ghcr.io/devcontainers/features/podman-in-podman #653 (podman devcontainer feature) — related area, already addressed.

[kaspergff]

Follow-up enhancement (prebuilt ghcr.io image) filed as #743.