[ako]

Implements mendixlabs#1518 (#1400), approved by the maintainer. This is a conservative rule at warning severity.

Rule: CONV020 (quality, warning)

CONV020 sits in mdl/linter/rules/conv_created_never_persisted.go. It flags a create when all of these hold:

• it is in a microflow (not a nanoflow or a rule);
• it is a CreateObjectAction with Commit stored explicitly as No;
• its entity is persistent, per the catalog;
• its output variable is never used in a way that keeps the object.

It walks the stored object graph (FullMicroflow, like CONV011).

Escapes. These are flow-insensitive, include loops and error handlers, and match whole words regardless of case. Any of the following keeps the rule quiet:

• the variable as a commit, delete or rollback target;
• a change with commit;
• the return value;
• any call argument (microflow, Java action, JavaScript action, workflow, export mapping);
• a show-page argument or passed object;
• added to a list;
• set as an association value on another object or on a new object;
• any bare $o in an expression.

Only reading a member ($o/Attr) or changing the object without commit does not count as a use, so an unknown action type also keeps it quiet. A commit on only one branch is an accepted false negative.

Tests

conv_created_never_persisted_test.go, 34 subtests:

• Positives: the issue's repro, a member read in a log message, a change without commit, a member read in a split or the return value, and a create inside a loop.
• Negatives: one per escape, plus a commit only in the error handler, and the out-of-scope cases (non-persistent entity, unstored commit value, created with commit, no output variable).

Revert check:

• With escape detection stubbed out, 19 negatives fail.
• If member reads count as uses, the 4 non-escape positives fail.

End to end: on an 11.15 fixture copy, mdl-examples/bug-tests/1518-created-object-never-persisted.mdl gives exactly one CONV020. The controls stay silent, and mx check reports 0 errors, so nothing else catches this.

False-positive survey

• Example scripts: 57 mdl-examples scripts containing create were executed into fresh fixture copies, then linted. That gave 70 creates with commit No and 7 hits, all read and all true positives: test fixtures whose object really is dropped.
• Studio Pro-authored flows: the Administration module in the blank 11.15 project and in a 9.x app had 6 creates each and 0 hits. That is correct: Account is passed on as an association value.

Docs: the docs-site/src/tools/builtin-rules.md rule row and a details section, linting.md, the mendix/lint command table, the assess-quality skill, and a CHANGELOG entry. make build, make test and make lint pass.

For review

• No check-time version. There is no mxcli check version of the rule, the way validate_commit_in_loop.go mirrors CONV011. That could be a follow-up.
• Not in the REPL: like CONV011, the rule isn't in the REPL lint list.

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