Fix silent drops of conditional expressions with keyword-named functions - #108
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`alter page … set Editable = [expr]` (and `set Visible`) produced a project
Studio Pro refused to open:
StorageLoadException: Conditional editability settings has an invalid
value '' for property Attribute
`Attribute` on Forms$Conditional{Visibility,Editability}Settings is a BY_NAME
AttributeIdentifier, so its unset value is the empty string, not null. The
CREATE path already encodes it that way — codec.RegisterTypeDefaults with
EmptyStringFields: {"Attribute"} in mdl/backend/modelsdk/widget_write.go,
whose comment records this exact StorageLoadException from mendixlabs#627. The ALTER
path builds the node by hand in setWidgetConditionalSettingMut and never got
the same treatment, so a widget authored through ALTER was unloadable while
the identical widget authored through CREATE was fine.
Neither `mxcli check` nor `mx check` inspects the stored value, so both
reported success on the broken project.
SourceVariable stays nil: it is a BY_ID reference, where null is the absent
value. "null is wrong here" is per-field, not a blanket rule.
Verified by dumping both encodings (`mxcli bson dump --type page`): a
CREATE-authored and an ALTER-authored widget now produce identical key sets
and values for both settings types.
Fixes mendixlabs#851
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013uQvFDd5R4eNqqita59jM8
…ssions `visible: [trim($currentObject/Slug) != '']` and `[length(...) > 0]` silently dropped the entire property. `xpathFunctionName` enumerated only IDENTIFIER, HYPHENATED_ID, NOT, TRUE, FALSE and CONTAINS, so a call to a function whose name is also an MDL lexer keyword never matched xpathFunctionCall. The enclosing `[...]` then failed to parse as an xpathConstraint and matched the generic property-value alternative instead, so the visitor set `Visible` to an array rather than `VisibleIf`, and the builder — which reads only a bool or a string from that slot — never fired. Nothing reported it: `mxcli check` passed, `mx check` passed, and a dropped Visible defaults to "always visible", so the only symptom was a widget that should have been hidden appearing in the running app. toUpperCase/isMatch (plain IDENTIFIERs) and contains (enumerated) were unaffected, which is what made the failure look arbitrary. Define the rule as `xpathWord | NOT` instead. xpathWord is the negated token set already used for name parts, so it self-maintains as the lexer gains keywords — an enumerated list would reacquire this bug with the next function name promoted to a token. This cannot swallow a path: xpathFunctionCall requires a following LPAREN and no xpathStepValue may be followed by one, so bare `empty` still parses as a word, which is what keeps `[Name = empty]` working. NOT is spelled out because xpathWord excludes it. The grammar deliberately does not enumerate a valid function set, because xpathConstraint serves two contexts with different ones: `Visible:`/`Editable:` is a Mendix client expression (trim/length/toUpperCase/find), while a datasource `where` is real XPath (contains/starts-with/ends-with/string-length/not, where `length()` means list length, the aggregates are Java-API-only, and empty/NULL are keywords rather than calls). One rule cannot encode both, so mxbuild adjudicates — it reports a wrong-context call as CE0117 against the real version's rules, which no table here could track. Also add MDL-WIDGET19 as the general guard, per the issue's request that encoding failures be loud: a `Visible`/`Editable` value that is neither routed to VisibleIf/EditableIf nor a recognized static form is the residue signature of any conditional the visitor could not build. It now fails `check` instead of disappearing on write. Verified by reverting the grammar fix and confirming the rule fires on the reported MDL. Verification, on a blank Mendix 11.6.6 app via `mxcli run --local` + Playwright (the repro script carries the Bug852.Verify page for this; Slug is three spaces so trim() changes the outcome): pre-fix all 5 markers render — TRIM_HIDDEN and LEN_HIDDEN should not post-fix only the 3 that should be visible render `mx check` reports 0 errors both ways, so this could only be confirmed in a browser. XPath regression checked too: `[Name = empty]`, `[Name = NULL]`, not(), contains(), starts-with() and string-length() all still parse and check clean. Behaviour change worth noting: `count(…)` and `empty(…)` are also keyword tokens and now parse, but they are not client-expression functions, so mxbuild now reports CE0117 where it previously saw nothing — the property having been dropped before reaching it. Loud beats silent, but anyone who had written one will newly see an error. Fixes mendixlabs#852 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013uQvFDd5R4eNqqita59jM8
`download file $Doc;` was accepted by the grammar, the visitor, the flow builder and `mxcli check`, and `mxcli exec` reported "Created microflow" — but microflowActionToGen had no *microflows.DownloadFileAction case, so the action hit `default: return nil` and the enclosing ActionActivity was serialized with no Action at all. DESCRIBE then rendered "-- Empty action" and `mx check` failed with CE0008 "No action defined." The statement passed every stage that reports something and disappeared at the one that reports nothing. This is the same silent-drop mechanism as the microflowObjectToGen default branch in mendixlabs#791. Add the case, setting FileDocumentVariableName, ShowFileInBrowser and ErrorHandlingType (Rollback default). The storage key is ShowFileInBrowser, not ShowInBrowser; the gen setter binds the right one (legacy's parseDownloadFileAction reads the wrong key — a latent legacy bug the existing reader test documents). Tested at the round trip rather than the reader. A reader-only test cannot catch this class: it starts from BSON the writer never had to produce, which is why TestActionFromGen_DownloadFile stayed green the whole time. The new test asserts the round-tripped ActionActivity has a non-nil Action — the CE0008 shape itself — and covers both the plain and `show in browser` forms. Fixes mendixlabs#850 Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013uQvFDd5R4eNqqita59jM8
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Brings the branch up to date with main (PRs #107, #108 and the commits behind them) so PR #109 merges cleanly and CI runs against the current base. No conflicts. The fix-issue.md symptom table merged via the union driver as intended — both this branch's rows and main's survive, with no duplicates. Full suite green on the merged tree. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_018hifgRSawfaRWXS44YKtSJ
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Summary
This PR fixes three related issues where MDL statements were silently dropped during parsing or writing, leaving no diagnostic trace:
trim()/length()in a widgetVisible/Editableexpression silently drop the whole property (contains(),toUpperCase()are fine) mendixlabs/mxcli#852: Widget conditionals calling functions whose names are MDL keywords (trim(),length(),find()) were silently dropped, leaving widgets unconditionally visible/editablealter page … set Editable = [expr]corrupts the project: StorageLoadException, .mpr will not load (CREATE/INSERT path is fine) mendixlabs/mxcli#851:alter page … set Editable = [expr]produced unopenable projects due to incorrect BSON encoding of theAttributefielddownload fileis parsed and built but never written: activity lands in the .mpr with no action (CE0008) mendixlabs/mxcli#850:download filemicroflow actions were parsed but never written, causing CE0008 "No action defined" at build timeKey Changes
Grammar & Parser (Issue mendixlabs#852)
mdl/grammar/domains/MDLPage.g4: Replaced enumeratedxpathFunctionNamerule withxpathWord(negated token set) plusNOT, allowing any function name including keywords. Added comprehensive documentation explaining why the grammar accepts any name and lets mxbuild adjudicate semantics.mdl/visitor/visitor_conditional_visibility_test.go: AddedTestConditionalVisibility_KeywordFunctionNamescoveringtrim(),length(),find(),count(),empty(), and non-keyword functions to prevent regression.Validation (Issue mendixlabs#852)
mdl/executor/validate_widgets.go: AddedvalidateConsumableConditional()function implementing MDL-WIDGET19 rule to detect unparseable conditional expressions that would be silently dropped on write.mdl/executor/validate_widgets_test.go: AddedTestValidateStaticWidget_UnconsumableConditionalcovering both flagged violations and valid static forms.Page Mutation (Issue mendixlabs#851)
mdl/backend/pagemutator/mutator.go: FixedsetWidgetConditionalSettingMut()to writeAttribute: ""(empty string) instead ofAttribute: nil. TheAttributefield is a BY_NAME AttributeIdentifier where unset must be"", notnull; a null causes Studio Pro to fail withStorageLoadException.mdl/backend/pagemutator/mutator_test.go: AddedTestSetWidgetConditionalSetting_AttributeIsEmptyStringwith helper functions to verify the BSON structure matches CREATE path behavior.Microflow Writing (Issue mendixlabs#850)
mdl/backend/modelsdk/microflow_write.go: Added missing*microflows.DownloadFileActioncase inmicroflowActionToGen()to write download file actions to BSON instead of falling through todefault: return nil.mdl/backend/modelsdk/microflow_downloadfile_test.go: AddedTestMicroflowRoundTrip_DownloadFileround-trip test covering bothShowInBrowservariants to catch write-side regressions.Documentation
.claude/skills/mendix/create-page.md: Added examples of keyword-named function calls in conditionals and a comparison table showing the different function sets for widget expressions vs. XPath constraints.mdl-examples/bug-tests/: Added three new test scripts:850-download-file-action.mdl: Verifiesdownload fileactions survive round-trip851-alter-page-conditional-attribute.mdl: Compares CREATE vs. ALTER conditional settings852-conditional-keyword-functions.mdl: Comprehensive test of keyword-named functions with runtime verification pageNotable Implementation Details
xpathConstraintserves two contexts (widget expressions vs. XPath) with different valid function sets.xpathWordis a negated token set, so it self-maintains as the lexer grows new keywords—an enumerated list would silently reacquire this bug.https://claude.ai/code/session_013uQvFDd5R4eNqqita59jM8