Can not update an entity instance after specification change

[Gorynych]

Steps to reproduce:

• Create a specification for entity:

key: PRODUCT-ORDERING
name: { en: "Product ordering" }
isApp: true
isAbstract: false
dataSpec: |
{
"type": "object",
"title": "Data",
"properties": {
"client": {
"title": "Client",
"type": "string"
}
}
}

• Validate & apply
• Go to the Applications -> Product ordering menu, and create a new Product ordering entity instance
• Then go back to specifications, and update the specification like this:

key: PRODUCT-ORDERING
name: { en: "Product ordering" }
isApp: true
isAbstract: false
dataSpec: |
{
"type": "object",
"title": "Product ordering information",
"properties": {
"client": {
"title": "Client",
"type": "object",
"properties": {
"firstName": {
"title": "First Name",
"type": "string"
},
"lastName": {
"title": "Last Name",
"type": "string"
}
}
}
}
}

• Go to the Applications -> Product ordering menu, and try to edit existing entity with some value in at least one of fields

Current behavior:
Internal server error message.

Logs:

xm2local_entity-app.1.ti8yb0m5rja9@linuxkit-025000000001 | 17:49:26.504 [XNIO-2 task-24] ERROR org.hibernate.internal.ExceptionMapperStandardImpl - HHH000346: Error during managed flush [failed to parse [data.client]]
xm2local_entity-app.1.ti8yb0m5rja9@linuxkit-025000000001 | 2019-05-03 17:49:26,514 ERROR [XNIO-2 task-24] [45NHgcP4:xm:XM] ServiceLoggingAspect: srv:stop: XmEntityServiceImpl:save, error: org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:545) ... com.icthh.xm.commons.logging.aop.ServiceLoggingAspect.logBeforeService(ServiceLoggingAspect.java:68)... -> javax.persistence.RollbackException: Error while committing the transaction org.hibernate.internal.ExceptionConverterImpl.convertCommitException(ExceptionConverterImpl.java:77) ... com.icthh.xm.commons.logging.aop.ServiceLoggingAspect.logBeforeService(ServiceLoggingAspect.java:68)... -> MapperParsingException[failed to parse [data.client]]; nested: IllegalStateException[Can't get text on a START_OBJECT at 1:194]; org.elasticsearch.index.mapper.FieldMapper.parse(FieldMapper.java:298) -> java.lang.IllegalStateException: Can't get text on a START_OBJECT at 1:194 org.elasticsearch.common.xcontent.json.JsonXContentParser.text(JsonXContentParser.java:88), time = 211 ms

Expected behavior:
To be discussed, but not 500.

Either

• specification should not be changed,
• or migration should be provided,
• or operator should confirm a data loss.