jamesfredley opened a new issue, #15506:
URL: https://github.com/apache/grails-core/issues/15506
## Summary
Tags defined in `RenderGrailsLayoutTagLib` (e.g., `pageProperty`,
`layoutTitle`, `layoutBody`) cannot be called as bare methods in GSP expression
syntax (`${pageProperty(name: 'meta.description')}`). They work correctly with
the explicit `g.` namespace prefix (`${g.pageProperty(name:
'meta.description')}`).
The root cause is that `RenderGrailsLayoutTagLib` has `@CompileStatic` at
class level, and `DefaultGrailsTagLibClass` tag discovery does not find
`Closure`-typed properties on `@CompileStatic` classes.
## Version
Grails 7.0.x (all versions since 7.0.0-M5, when `RenderGrailsLayoutTagLib`
was introduced). Tested on 7.0.9-SNAPSHOT.
## Steps to Reproduce
1. Create a layout GSP (e.g., `layouts/marketing.gsp`)
2. Use `pageProperty` as a bare method call in a GSP expression:
```gsp
<meta name="description" content="${pageProperty(name:
'meta.description') ?: 'default'}"/>
```
3. Visit a page that uses this layout
**Expected:** The page renders normally, `pageProperty` resolves to the tag
from `RenderGrailsLayoutTagLib`.
**Actual:** 500 error: `No signature of method:
...marketing_gsp.pageProperty() is applicable for argument types:
(LinkedHashMap)`
## Workaround
Using the explicit `g.` namespace prefix works:
```gsp
<meta name="description" content="${g.pageProperty(name: 'meta.description')
?: 'default'}"/>
```
This is because `g.pageProperty()` goes through
`GroovyPage.getProperty("g")` -> `NamespacedTagDispatcher` ->
`TagLibraryLookup.lookupTagLibrary()`, which is a different resolution path
that works correctly.
## Root Cause Analysis
### Tag discovery mechanism
`DefaultGrailsTagLibClass` (line 62-71) discovers tags by iterating
metaclass properties:
```java
for (MetaProperty prop :
GroovySystem.getMetaClassRegistry().getMetaClass(clazz).getProperties()) {
int modifiers = prop.getModifiers();
if (Modifier.isStatic(modifiers) || !Modifier.isPublic(modifiers)) {
continue;
}
if (Closure.class.isAssignableFrom(prop.getType())) {
tags.add(prop.getName());
}
}
```
When a TagLib class has `@CompileStatic`, Groovy 4 compiles the `Closure`
property fields differently. The metaclass property type no longer reports as
`Closure`, so `Closure.class.isAssignableFrom(prop.getType())` returns false,
and the tags are not registered.
### Two resolution paths
| Call syntax | Resolution path | Works? |
|---|---|---|
| `g.pageProperty(name: ...)` | `GroovyPage.getProperty("g")` ->
`NamespacedTagDispatcher.methodMissing` ->
`TagLibraryLookup.lookupTagLibrary("g", "pageProperty")` | Yes |
| `pageProperty(name: ...)` | `ExpandoMetaClass.methodMissing` ->
`TagLibraryMetaUtils.methodMissingForTagLib` ->
`TagLibraryLookup.lookupTagLibrary("g", "pageProperty")` | No |
Both paths use the same `TagLibraryLookup`. The bare method path fails
because the tag was never registered in the lookup's `tagNamespaces` map (due
to the property scanning issue above). The `g.` path works because the
`NamespacedTagDispatcher` has its own `methodMissing` that still finds the bean.
### Confirmed by test
Locally removed `@CompileStatic` from `RenderGrailsLayoutTagLib`, published
to mavenLocal, and tested: **bare `pageProperty()` works correctly after
removal**. Re-adding `@CompileStatic` breaks it again.
### Affected TagLib
`RenderGrailsLayoutTagLib` in `grails-layout` module is the only framework
TagLib with class-level `@CompileStatic`. Other built-in TagLibs (e.g.,
`ApplicationTagLib`, `FormTagLib`, `RenderTagLib`) do not have class-level
`@CompileStatic` and their tags work as bare methods.
### History
`RenderGrailsLayoutTagLib` was introduced in commit `0be9f5d486` ("revert
sitemesh3 upgrade & rename sitemesh -> layout") included in 7.0.0-M5. The
class-level `@CompileStatic` was present from its creation. The prior
`RenderSitemeshTagLib` (Sitemesh 3, since reverted) did not have
`@CompileStatic`.
## Affected tags
All tags in `RenderGrailsLayoutTagLib`:
- `pageProperty`
- `ifPageProperty`
- `layoutTitle`
- `layoutHead`
- `layoutBody`
- `applyLayout`
- `content`
## Note on documentation
The [official pageProperty
docs](https://grails.apache.org/docs/7.0.0/ref/Tags%20-%20GSP/pageProperty.html)
show `${pageProperty(name:'body.onload')}` without the `g.` prefix, which does
not work due to this bug.
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