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https://issues.apache.org/jira/browse/GROOVY-12191?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18099443#comment-18099443
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ASF GitHub Bot commented on GROOVY-12191:
-----------------------------------------
daniellansun commented on code in PR #2736:
URL: https://github.com/apache/groovy/pull/2736#discussion_r3657316553
##########
src/main/java/org/codehaus/groovy/vmplugin/v8/IndyInterface.java:
##########
@@ -215,29 +216,86 @@ public int getOrderNumber() {
}
/**
- * Shared switch point invalidated when metaclass state changes.
+ * Legacy process-wide SwitchPoint retained for binary compatibility only.
+ * <p>
+ * <strong>Behavioral change in 6.0 (GROOVY-12191):</strong> MetaClass
changes
+ * are scoped per {@link org.codehaus.groovy.reflection.ClassInfo}. This
field
+ * is <em>not</em> the MOP guard on linked call sites and is <em>not</em>
+ * rotated on per-class MetaClass changes. It is rotated only when
+ * {@link #invalidateSwitchPoints()} runs — i.e. category enter/leave and
+ * {@code VMPlugin.invalidateCallSites()} — so external observers of this
+ * field still see those bulk events. Guarding a site on this field alone
+ * will <strong>silently miss</strong> type-scoped MetaClass invalidations;
+ * migrate to {@link IndyInvalidation#guardWithMopSwitchPoints}.
+ *
+ * @see IndyInvalidation
+ * @deprecated since 6.0.0 — use {@link
IndyInvalidation#guardWithMopSwitchPoints};
+ * this field is not the call-site MOP guard and is not
rotated on
+ * per-class MetaClass changes.
*/
- protected static SwitchPoint switchPoint = new SwitchPoint();
+ @Deprecated(since = "6.0.0", forRemoval = false)
+ protected static volatile SwitchPoint switchPoint = new SwitchPoint();
Review Comment:
Agreed — thank you.
`org.codehaus.groovy.vmplugin.*` is internal-by-intent. Keeping a dead
process-wide `SwitchPoint` only for binary compatibility was weaker than a
clean removal: after scoping, the field was no longer the MOP guard and was
rotated only on bulk paths, which was easy to misread.
**Action taken**
- Removed `protected static SwitchPoint switchPoint` entirely.
- `invalidateSwitchPoints()` now only bulk-retires per-class domains via
`IndyInvalidation.invalidateCategory()` (no legacy field rotation, no
`volatile`, no extra lock).
- Docs/`package-info` updated; tests no longer assert on the removed field.
The earlier `volatile` was only there to make concurrent bulk rotation of
that legacy field observable; with the field gone, that concern disappears.
> Scope indy SwitchPoint invalidation
> -----------------------------------
>
> Key: GROOVY-12191
> URL: https://issues.apache.org/jira/browse/GROOVY-12191
> Project: Groovy
> Issue Type: Improvement
> Reporter: Daniel Sun
> Priority: Major
> Fix For: 6.0.0-beta-1
>
>
> h3. Problem
> With invokedynamic enabled (default since Groovy 4), linked MOP call sites
> were guarded by a *single process-wide* {{SwitchPoint}}
> ({{{}IndyInterface.switchPoint{}}}).
> Any MetaClass registry change or category enter/leave invalidated that switch
> point, so *every* linked site fell back and re-linked — including sites whose
> receiver type was unrelated.
> That global invalidation is expensive when MetaClass churn is common (e.g.
> ExpandoMetaClass / mixins on startup or per-request paths, Grails-like
> patterns). Unrelated hot monomorphic sites pay re-link and JIT deopt cost
> they should not.
> h3. Goal
> Keep linked call sites optimized unless the *relevant* MetaClass state for
> that site actually changed.
> h3. Approach
> One SwitchPoint domain {*}per class{*}, stored on {{{}ClassInfo{}}}:
> * MetaClass change for type {{T}} retires {{{}T{}}}'s SwitchPoint *and*
> those of loaded subtypes / implementors (hierarchy fan-out).
> * Unrelated types keep their SwitchPoints; their call sites stay optimized.
> * Category enter/leave (and {{{}VMPlugin.invalidateCallSites(){}}})
> bulk-retire *all* loaded class SwitchPoints so sites re-link under the new
> category state. There is *no* second category SwitchPoint on the hot path.
> * Linked handles always install a *single* class-domain guard via
> {{IndyInvalidation.guardWithMopSwitchPoints(...)}} — same monomorphic guard
> shape as before, without global deopt on unrelated MetaClass churn.
> Final classes short-circuit hierarchy fan-out (no full {{ClassInfo}} scan).
> Non-final types batch retirements with {{{}SwitchPoint.invalidateAll{}}}.
> h3. Invalidation map
> ||Event||What is retired||
> |MetaClass change for type {{T}} (registry /
> {{{}ClassInfo.incVersion{}}})|{{T}} + loaded subtypes / implementors|
> |Category enter/leave, {{invalidateCallSites()}}|All loaded class
> SwitchPoints (bulk)|
> |Unattributed MetaClass registry event|All loaded class SwitchPoints (bulk)|
> |First MetaClass *install* on a class|Version bump only (no linked sites
> yet); replacement / clear retires that class's SwitchPoint|
>
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