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https://issues.apache.org/jira/browse/GROOVY-12015?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Paul King updated GROOVY-12015:
-------------------------------
Description:
{code:none}
h3. Summary
Extends {{copyWith}} (generated for {{@Immutable}} and {{@RecordType}}
classes declared with {{copyWith=true}}) with nested-path support and a
transactional block form, for ergonomic updates of immutable object graphs.
h3. Nested-path map form
A {{copyWith}} key may now be a dotted path; the affected nested nodes are
rebuilt recursively and untouched branches are reused.
{code:groovy}
def q = p.copyWith('address.city': 'NYC', 'address.zip': '10001')
{code}
* Works for arbitrarily deep paths and heterogeneous {{@Immutable}}/
{{@RecordType}} graphs (record-in-record included).
* Plain (non-dotted) keys behave exactly as before.
* Identity is preserved transitively: if nothing changes, the original
instance is returned.
* Every node on a nested path must itself provide {{copyWith(Map)}};
otherwise a clear, specific error is raised.
h3. Transactional block form
A {{copyWith(Closure)}} overload is also generated:
{code:groovy}
def q = p.copyWith {
name = 'Bob' // plain set
address.city = old.address.city.reverse() // derive from the original
fullName = old.first + ' ' + old.last // cross-field derivation
loginCount.modify { it + 1 } // single-field shorthand
}
{code}
* {{old}} resolves to the original (pre-state) object, consistent with
{{old}} in {{@Ensures}}/{{@Contract}}, and may be used to derive any new
value, including across fields.
* {{prop.modify { }}} is a shorthand for the common
transform-this-same-field case.
* To invoke a real same-named {{modify}} method on a value type (or simply
for readability), use the {{old}} form: {{x = old.x.modify { ... }}}.
* An empty or no-op block returns the original instance.
h3. Compatibility
* A no-arg {{copyWith()}} is generated, returning the same instance
(preserving the historical zero-argument behaviour).
* Existing single-level and Map-based {{copyWith}} usage is unchanged.
* Shared generation logic is used by both the {{@Immutable}} and
{{@RecordType}} transforms so behaviour stays identical across the two.
{code}
No spike/option/decision language included — purely the delivered behaviour, in
Jira markup. Let me know if you want it tightened further or split into Summary
vs. Acceptance Criteria fields.
> Provide a nested copyWith capability
> ------------------------------------
>
> Key: GROOVY-12015
> URL: https://issues.apache.org/jira/browse/GROOVY-12015
> Project: Groovy
> Issue Type: New Feature
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
> {code:none}
> h3. Summary
> Extends {{copyWith}} (generated for {{@Immutable}} and {{@RecordType}}
> classes declared with {{copyWith=true}}) with nested-path support and a
> transactional block form, for ergonomic updates of immutable object graphs.
> h3. Nested-path map form
> A {{copyWith}} key may now be a dotted path; the affected nested nodes are
> rebuilt recursively and untouched branches are reused.
> {code:groovy}
> def q = p.copyWith('address.city': 'NYC', 'address.zip': '10001')
> {code}
> * Works for arbitrarily deep paths and heterogeneous {{@Immutable}}/
> {{@RecordType}} graphs (record-in-record included).
> * Plain (non-dotted) keys behave exactly as before.
> * Identity is preserved transitively: if nothing changes, the original
> instance is returned.
> * Every node on a nested path must itself provide {{copyWith(Map)}};
> otherwise a clear, specific error is raised.
> h3. Transactional block form
> A {{copyWith(Closure)}} overload is also generated:
> {code:groovy}
> def q = p.copyWith {
> name = 'Bob' // plain set
> address.city = old.address.city.reverse() // derive from the original
> fullName = old.first + ' ' + old.last // cross-field derivation
> loginCount.modify { it + 1 } // single-field shorthand
> }
> {code}
> * {{old}} resolves to the original (pre-state) object, consistent with
> {{old}} in {{@Ensures}}/{{@Contract}}, and may be used to derive any new
> value, including across fields.
> * {{prop.modify { }}} is a shorthand for the common
> transform-this-same-field case.
> * To invoke a real same-named {{modify}} method on a value type (or simply
> for readability), use the {{old}} form: {{x = old.x.modify { ... }}}.
> * An empty or no-op block returns the original instance.
> h3. Compatibility
> * A no-arg {{copyWith()}} is generated, returning the same instance
> (preserving the historical zero-argument behaviour).
> * Existing single-level and Map-based {{copyWith}} usage is unchanged.
> * Shared generation logic is used by both the {{@Immutable}} and
> {{@RecordType}} transforms so behaviour stays identical across the two.
> {code}
> No spike/option/decision language included — purely the delivered behaviour,
> in Jira markup. Let me know if you want it tightened further or split into
> Summary vs. Acceptance Criteria fields.
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