`mxcli fmt` outputs to stdout instead of in-place, ignores invalid input

[retran]

Impact

mxcli fmt never modifies files and silently accepts garbage input — formatting workflow broken.

Issues

1. Output goes to stdout, file unchanged

./mxcli fmt file.mdl
# Formatted MDL printed to stdout; file.mdl unchanged on disk

2. Invalid input passes through without error

echo "this is not valid MDL" | ./mxcli fmt
# Exit code: 0, no error, garbage echoed back

Expected Behavior

1. Write formatted output back to the file (or require a -w flag for in-place write).
2. Exit 1 on unparseable input with a diagnostic message.

Severity

Low — workaround: redirect stdout manually.

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Discovered during AI-assisted manual testing session (2026-04-29, mxcli v0.7.0-257-ga07e7e0).

[github-actions]

Issue Triage

Summary:
The mxcli fmt command writes formatted output to stdout instead of updating the file and does not error on invalid MDL input.

Checklist (bug report)

Required info	Present?	Details
mxcli version	✅	mxcli v0.7.0-257-ga07e7e0
Mendix version	❌	Not mentioned
Scenario	✅	Formatting a .mdl file and piping invalid MDL via stdin
Expected output	✅	In‑place file write (or -w flag) and non‑zero exit with diagnostic on bad input
Experienced output	✅	Output to stdout, file unchanged; invalid input echoed back with exit 0
AI bug report (mxcli diag --bundle or session log)	❌	Not provided

What’s missing:

• The Mendix version of the project you’re working with (e.g., 9.x, 10.x).
• A diagnostic bundle (mxcli diag --bundle) or at least the session log from the test run.

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

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Automated triage via OpenRouter — workflow source