Paul King created GROOVY-12634:
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Summary: groovy-lsp: hover on a constructor call shows a fragment
of the type name instead of the constructor
Key: GROOVY-12634
URL: https://issues.apache.org/jira/browse/GROOVY-12634
Project: Groovy
Issue Type: Bug
Reporter: Paul King
Hovering over a constructor call does not describe the constructor or the type
being instantiated. The hover instead shows the part of the word that lies
before the hovered character.
For the script:
{code:groovy}
println new Date()
{code}
hovering at these 0-based UTF-16 columns gives:
||Column||Character||Hover content||
|9|{{e}} in {{new}}|{{n}}|
|12|{{D}}|(no hover)|
|13|{{a}}|{{D}}|
|14|{{t}}|{{Da}}|
|15|{{e}}|{{Dat}}|
Hover on {{println}} works as expected ({{void Script.println(Object arg0)}}).
The script compiles without diagnostics.
h3. Cause
* {{HoverService.resolveForHover()}} only resolves a {{MethodCallExpression}}.
A {{ConstructorCallExpression}} is passed through unchanged.
* {{HoverService.render()}} has no case for {{ConstructorCallExpression}}, so
it returns {{null}}.
* A {{null}} result falls through to {{identifierHover()}}, which uses
{{CompletionService.prefixAt()}}. That returns the identifier text before the
caret, which gives the fragments above (see the separate issue on the fallback).
The other features already handle constructor calls: signature help
({{SignatureHelpService}}), navigation ({{NavigationService}}) and the type
hierarchy ({{HierarchyService}}). {{MethodBinding.resolveConstructor()}}
already picks a unique constructor by argument count.
h3. Expected
* When a unique constructor matches the call, hover shows its signature and
Groovydoc, for example {{new Date()}}.
* When no single constructor matches (overloads with the same argument count,
or an anonymous inner class), hover falls back to the instantiated type, for
example {{class java.util.Date}}.
h3. Notes
{{ConstructorNode}} extends {{MethodNode}}. If it is passed to the existing
method rendering, the hover would read {{void Date.<init>()}}, so constructors
need their own rendering placed before the {{MethodNode}} case.
Tests should cover hovering on the first, a middle and the last character of
the type name, the {{new}} keyword, and a type whose constructors share an
argument count.
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