feat(microflows): expose the Commit flag on create/change activities (#779)

[ako]

Fixes mendixlabs#779.

Stacked on #66 — base is claude/microflow-mandatory-semicolons, not main. Merge #66 first; this will then retarget to main on its own. The dependency is real: mandatory statement semicolons are what make the commit modifier unambiguous against the standalone commit $Var activity.

The issue asks for a display feature. The actual defect is a write bug.

mendixlabs#779 reports that DESCRIBE MICROFLOW cannot distinguish a create/change with Commit enabled from one without. True — but the more serious half is that MDL had no syntax for the flag and the builder hardcoded it:

mdl/executor/cmd_microflows_builder_actions.go:95   Commit: microflows.CommitTypeNo,
mdl/executor/cmd_microflows_builder_actions.go:241  Commit: microflows.CommitTypeNo,

Every create/change mxcli authored was written as Commit: No regardless of intent, so a describe → edit → re-exec round-trip silently converted committing activities into non-committing ones. That is the object-orphaning failure mode the reporter describes chasing in Studio Pro — this may explain their original bug, not merely help them find the next one.

Three commits

4ba3cbc — declare the Commit values Mendix actually defines. CommitType declared "YesWithEvents" and "NoEvent", neither of which exists in the metamodel; the canonical set is Yes / YesWithoutEvents / No. Nothing crashed, because the read path passes the stored string through untouched — but the named constants matched nothing in a real project, so code switching on them fell through to its default. The giveaway was mdl/backend/mcp, whose mfCommitType had to translate CommitTypeNoEvent into "YesWithoutEvents", mapping a constant named "no events" onto "yes, without events". A new test pins the set against the generated CommitEnum in both directions.

8704b58 — the syntax. Follows the existing refresh modifier on change:

$Order = create Sales.Order (Number = 'X');                        -- No (default)
$Order = create Sales.Order (Number = 'X') commit;                 -- Yes
$Order = create Sales.Order (Number = 'X') commit without events;  -- YesWithoutEvents
change $Order (Status = 'Paid') commit refresh;

The default stays unwritten, so existing scripts are unaffected and enabling the flag is a one-word diff. Wired grammar → AST (CommitFlag) → visitor (buildCommitClause) → builder (commitTypeOf).

34a93ed — DESCRIBE emission. The value was already read by both engines; the formatter simply never looked at it. Canonical order on change is commit [without events] then refresh, matching the grammar.

Ordering note

I did grammar before DESCRIBE rather than the other way round. Emitting a modifier the parser could not read would have left describe output unparseable in between — a worse regression than the bug being fixed.

Tests

• Parse: all three values on create and change, with and without member lists, with on error, with refresh, and refresh alone.
• Ambiguity guards — a create followed by commit $O; must yield two statements with the create flagged No; a create carrying the modifier and followed by a commit activity must keep both.
• Round-trip (TestFormatAction_CommitRoundTrips) — formats each value, re-parses the emitted MDL through the visitor, requires the flag back identical. This is Feature Request: Expose Commit flag on CREATE/CHANGE activities in DESCRIBE MICROFLOW mendixlabs/mxcli#779's second acceptance criterion, asserted rather than assumed.
• mdl-examples/doctype-tests/779-commit-flag.mdl covering every variant plus the modifier sitting next to a standalone COMMIT activity.

Full suite green. Corpus at 235 / 39 — the +1 over baseline is the new example file.

Docs

MDL_QUICK_REFERENCE.md create/change rows, write-microflows.md CREATE and CHANGE sections, and the microflow.object-operations syntax topic. Each spells out that commit on create/change is a modifier, not the standalone commit $Var; activity — the thing most likely to be confused.

🤖 Generated with Claude Code

https://claude.ai/code/session_012XR649rKk68z6gBpngu6MA

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