AnnotationFileParser: accept a stub record whose library type is a class

checker/jtreg/stubs/recordstubclass/Outer.astub

@@ -0,0 +1,13 @@
+package recordstubclass;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class Outer {
+    // The class is a record here but a plain class in the library, as when the annotated JDK
+    // (written for a newer JDK) declares a record that the JDK running the checker has as a class.
+    // Component "missing" has no field in the library.
+    public record Inner(Object f, Object missing) {}
+
+    // Declared after the record: it was lost when the record aborted the processing of Outer.
+    public @Nullable Object get();
+}

checker/jtreg/stubs/recordstubclass/Outer.java

@@ -0,0 +1,12 @@
+package recordstubclass;
+
+/** A library class whose nested class is a record in the annotated stub (see Outer.astub). */
+public class Outer {
+    public static class Inner {
+        public final Object f = new Object();
+    }
+
+    public Object get() {
+        return new Object();
+    }
+}

checker/jtreg/stubs/recordstubclass/Use.java

@@ -0,0 +1,18 @@
+/*
+ * @test
+ * @summary A record in a stub file whose library type is a class must not stop the processing of
+ *     the members that follow it.
+ *
+ * @compile Outer.java
+ * @compile/fail/ref=Use.out -XDrawDiagnostics -processor org.checkerframework.checker.nullness.NullnessChecker -Anomsgtext -Astubs=Outer.astub Use.java
+ */
+
+package recordstubclass;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+public class Use {
+    void g(Outer o) {
+        @NonNull Object x = o.get();
+    }
+}

checker/jtreg/stubs/recordstubclass/Use.out

@@ -0,0 +1,4 @@
+- compiler.warn.proc.messager: Outer.astub:(line 9,col 35): field missing not found in type recordstubclass.Outer.Inner
+Use.java:16:34: compiler.err.proc.messager: (assignment.type.incompatible)
+1 error
+1 warning

docs/CHANGELOG.md

@@ -153,6 +153,10 @@ Command-line option additions and changes:
 - Invalid option arguments (e.g. malformed regex) now produce compiler errors
   instead of stack traces.
 
+A stub file that declares a record where the running JDK has a class (for example
+the JDK 21 annotated JDK on JDK 8 to 17) no longer loses the annotations of the
+members that follow the record.
+
 ### Implementation details
 
 Performance optimizations:

framework/src/main/java/org/checkerframework/framework/stub/AnnotationFileParser.java

@@ -1194,14 +1194,21 @@ private String javaParserNodeToStringTruncated(Node n, int length) {
             Map<String, RecordComponentStub> byName =
                     ArrayMap.newArrayMapOrLinkedHashMap(recordMembers.size());
             for (Parameter recordMember : recordMembers) {
-                RecordComponentStub stub =
-                        processRecordField(
-                                recordMember,
-                                findFieldElement(
-                                        typeElt, recordMember.getNameAsString(), recordMember));
-                byName.put(recordMember.getNameAsString(), stub);
+                VariableElement componentElt =
+                        findFieldElement(typeElt, recordMember.getNameAsString(), recordMember);
+                // Null if the type is a class without a field for the component; see
+                // findFieldElement, which already reported it.
+                if (componentElt != null) {
+                    byName.put(
+                            recordMember.getNameAsString(),
+                            processRecordField(recordMember, componentElt));
+                }
+            }
+            // A record in the stub file can be a class in the running JDK; only a record element
+            // has components, and the binary stub files likewise store no record for a class.
+            if (ElementUtils.isRecordElement(typeElt)) {
+                putMergeRecords(recordDecl.getFullyQualifiedName().get(), new RecordStub(byName));
             }
-            putMergeRecords(recordDecl.getFullyQualifiedName().get(), new RecordStub(byName));
         }
 
         Pair<Map<Element, BodyDeclaration<?>>, Map<Element, List<BodyDeclaration<?>>>> members =
@@ -1236,8 +1243,11 @@ private String javaParserNodeToStringTruncated(Node n, int length) {
                     break;
                 case CLASS:
                 case INTERFACE:
+                    // The declaration is a record when the stub file was written for a newer JDK
+                    // than the one that is running: a class that became a record keeps its name,
+                    // and its element is still a class here.
                     // Not processing an ajava file, so ignore the return value.
-                    processTypeDecl((ClassOrInterfaceDeclaration) decl, innerName, null);
+                    processTypeDecl((TypeDeclaration<?>) decl, innerName, null);
                     break;
                 case ENUM:
                     // Not processing an ajava file, so ignore the return value.