`mxcli new` exits 0 on download failure

[retran]

Description

mxcli new --version 10.24.15 receives HTTP 404 (no arm64 binary available) but exits with code 0 instead of non-zero.

Steps to Reproduce

./mxcli new --version 10.24.15
echo $?  # prints 0

Also: mxcli new without --version gives "Error: --version is required" but exits 0.

Expected

• Exit 1 on download failure (HTTP 404).
• Exit 1 on missing required flags.

Severity

Medium — CI scripts and automation cannot detect failures.

Reproducing test cases

• cli-commands-test-cases.md § 12.1, 12.2

[github-actions]

Issue Triage

Summary:
The mxcli new command exits with status 0 even when it encounters an HTTP 404 while downloading a Mendix version or when a required --version flag is omitted.

Checklist of required bug‑report information

Required info	Present?	Details
mxcli version (output of mxcli --version or commit/build)	❌	Not provided
Mendix version of the project being processed	✅	User attempts to download Mendix 10.24.15
Scenario (what the user was trying to do)	✅	Running mxcli new --version 10.24.15 and mxcli new without --version
Expected output	✅	Should exit with non‑zero code on download failure or missing flag
Experienced output	✅	Exits 0 despite HTTP 404 or missing flag
AI bug report (mxcli diag --bundle or session log)	❌	Not included

What’s missing:

• The version of mxcli you’re using (run mxcli --version and share the output).
• A diagnostic bundle or at least the session log from mxcli diag --bundle (or the relevant log excerpt) to help us see the internal error handling.

Could you please add those details? Once we have them, we’ll be able to investigate and fix the exit‑code behavior. Thanks for reporting this!

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Automated triage via OpenRouter — workflow source

[ako]

Investigated and fixed the confirmed bug. Here's the breakdown:

Bug 1 — Step 4 download failure exits 0 (confirmed, now fixed)

When running on macOS/Windows, mxcli new downloads a Linux mxcli binary for the devcontainer (step 4). If that download fails (HTTP 404 — e.g. no binary for the current release tag), the code printed only a warning and continued, exiting 0. Fixed in this branch by changing the warning to a hard error with os.Exit(1):

Error: could not download Linux mxcli binary for devcontainer: downloading mxcli: HTTP 404 from ...
  Run 'mxcli setup mxcli --output ./mxcli' inside the project directory to fix this.

Also extracted downloadMxcliBinaryFromURL helper so the behavior is covered by unit tests using httptest.Server.

Bug 2 — Missing --version exits 0 (cannot reproduce)

The current code calls os.Exit(1) when mendixVersion == "" — this was present from the original commit (2026-04-04). The --version flag is not marked required in Cobra, so it's validated manually inside Run before any downloads start. I could not find a code path where the process would exit 0 for this case with the current code.