Paul King created GROOVY-12701:
----------------------------------
Summary: @ASTTest on a declaration with several declarators fails
with "BUG! ... Tried to overwrite existing meta data"
Key: GROOVY-12701
URL: https://issues.apache.org/jira/browse/GROOVY-12701
Project: Groovy
Issue Type: Bug
Components: Compiler
Affects Versions: 6.0.0, 5.1.3, 4.0.32
Reporter: Paul King
h3. Description
{{@ASTTest}} on a local variable declaration or field declaration with more
than one declarator makes the compiler fail with a {{GroovyBugError}}, whatever
the test closure does:
{code:groovy}
import groovy.transform.ASTTest
import org.codehaus.groovy.ast.expr.DeclarationExpression
def m() {
@ASTTest(value={
assert node instanceof DeclarationExpression
})
def a = 1, b = 2
a + b
}
println m()
{code}
{noformat}
BUG! exception in phase 'semantic analysis' in source unit '...' Tried to
overwrite existing meta data
org.codehaus.groovy.ast.AnnotationNode@...[@groovy.transform.ASTTest(phase=...,
value={ ... })].
{noformat}
The same happens for fields:
{code:groovy}
import groovy.transform.ASTTest
class F {
@ASTTest(value={
assert node.name in ['x', 'y']
})
int x = 1, y = 2
}
{code}
and for any {{phase}}. A single declarator ({{def a = 1}}) and a multiple
assignment ({{def (a, b) = [1, 2]}}) work.
Expected: the test closure runs once for each declared variable or field, with
{{node}} bound to that declaration, as other local AST transformations are
invoked for each declarator.
Reproduced with 4.0.32, 5.1.3, 6.0.0 and master.
h3. Cause
The parser attaches the same {{AnnotationNode}} instance to every declarator of
the declaration ({{def a = 1, b = 2}} becomes two {{DeclarationExpression}}s,
{{int x = 1, y = 2}} two {{FieldNode}}s, sharing the annotation).
{{ASTTransformationVisitor}} therefore calls {{ASTTestTransformation#visit}}
once per declarator with the same annotation node.
On the first call, {{ASTTestTransformation}} moves the test closure out of the
annotation into node metadata and replaces the {{value}} member with an empty
closure:
{code:groovy}
annotationNode.setNodeMetaData(ASTTestTransformation, member)
annotationNode.setMember('value', new ClosureExpression(Parameter.EMPTY_ARRAY,
EmptyStatement.INSTANCE))
{code}
On the second call {{setNodeMetaData}} finds the key already set and throws.
Even if it did not, it would store the empty replacement closure as the test.
h3. Suggested fix
In {{ASTTestTransformation#visit}}, do the conversion only the first time an
annotation node is seen: if the node metadata is already set, reuse the stored
test closure, skip the {{value}} checks and the replacement, and register an
{{ASTTester}} for the current node ({{nodes[1]}}). The {{phase}} member is
already rewritten into a form that the second call reads correctly.
This is a general hazard for local transformations that keep state on the
annotation node: with several declarators, the same annotation node is passed
for each annotated node.
--
This message was sent by Atlassian Jira
(v10.3.26#10030026)
