fix(forms): an optional field with a format constraint must accept empty

[delchev]

What

A blank optional field cannot be saved.

Creating a Customer with only the required Name fails with "Could not save — Fields that need attention: Email" / "Enter a valid email address.", even though Email is not required. The only way through is to invent an address — which then pollutes the data, since the dunning and notify paths mail whatever is stored there.

Cause

Both layers applied the format rule to the empty value:

• Client (application-core formValidation.js) ran every rule regardless of presence, so the email rule on an optional field rejected ''.
• Server (EntityController.java.template) guarded the pattern on != null only, so a direct REST caller sending "" got a 400. The Harmonia form already posts '' as null, so this path is REST-only.

A format constraint describes what a value must look like when there is one. Presence is required's decision alone; applying a format rule to an empty value makes every optional field carrying one required by the back door.

Fix

Client — skip any non-required rule when the value is blank. This covers email / pattern / minLength / min / max alike. No required field loses its check: the generator emits either the required rule or the format rule for a given field, never both.

This file is the shared runtime, so every generated app picks the fix up without a regen.

Server — emit the blank skip only for optional properties:

// optional + pattern
if (entity.Email != null && !entity.Email.toString().isBlank() && !entity.Email.toString().matches(...))
// required + pattern — unchanged
if (entity.Code != null && !entity.Code.toString().matches(...))

A required property keeps the strict check, where blank is not a legal value — so nothing that is rejected today starts passing. Modules pick this up on their next regen.

Verification

• The client validator against 11 cases: blank / null / whitespace accepted on an optional email; "abc" still refused; required still fails on '' and null; optional minLength/min skip empty but still fail a present bad value.
• The controller template rendered through a real Velocity engine with an optional-patterned and a required-patterned property, confirming the emitted Java gains && !isBlank() on the optional one only, and is byte-identical for the required one.

🤖 Generated with Claude Code