val someVal: String? = null
                    var someVar: String? = null
                    fun foo(): String? = null
                }
            """
        ) {
            assertHasErrors(
                "Method com.example.Source.foo(): From non-null returning to null returning breaking change.",
                "Method com.example.Source.getSomeVal(): From non-null returning to null returning breaking change.",

                null, // effectiveModel is null
                null, // rawModel is null
                createMockModel("com.example", "test-project", "1.0.0") // fileModel is available
                );

        String projectId = (String) extractProjectIdMethod.invoke(null, mockResult);

        assertNotNull(projectId, "Project ID should not be null");
        assertEquals(

// indicates if this is the last version.
func (x *xlMetaV2) DeleteVersion(fi FileInfo) (string, error) {
	// This is a situation where versionId is explicitly
	// specified as "null", as we do not save "null"
	// string it is considered empty. But empty also
	// means the version which matches will be purged.
	if fi.VersionID == nullVersionID {
		fi.VersionID = ""
	}

	var uv uuid.UUID

                                    propertyName, valueClass == null ? null : valueClass.getName(),
                                    valueClass == null ? null : valueClass.getClassLoader(), convertedValue,
                                    targetClass == null ? null : targetClass.getName(),
                                    targetClass == null ? null : targetClass.getClassLoader() }).initCause(t);
                }

        // Filter accepts only when name is exactly null, otherwise false
        SmbFilenameFilter filter = (dir, n) -> n == null;

        boolean result = filter.accept(mockDir, name);

        if (name == null) {
            assertTrue(result, "Null name should be accepted by this filter");
        } else {
            assertFalse(result, "Non-null names should be rejected by this filter");
        }

                }
            """
        ) {
            assertHasErrors(
                "Method com.example.Source.foo(): From non-null returning to null-unmarked returning breaking change.",
                "Method com.example.Source.baz(): From non-null returning to null-unmarked returning breaking change.",
            )
            assertHasNoWarning()

           * will always copy any entry objects that cannot be safely reused.
           */
          if (valueComparator != null) {
            if (entriesUsed) {
              entries = Arrays.copyOf(entries, size);
            }
            sort(
                (Entry<K, V>[]) entries, // Entries up to size are not null
                0,
                size,
                Ordering.from(valueComparator).onResultOf(Entry::getValue));

    }
    // ------------------------------------------------------------------------
    public MetadataGraphVertex addVertex(ArtifactMetadata md) {
        if (md == null) {
            return null;
        }

        checkVertices();

        MetadataGraphVertex v = findVertex(md);
        if (v != null) {
            return v;
        }

        v = new MetadataGraphVertex(md);

        // and we want artifact resolution to only return the system scoped artifact itself.
        //
        if (artifact.getScope() != null && artifact.getScope().equals(Artifact.SCOPE_SYSTEM)) {
            return new ResolutionGroup(null, null, null);
        }

        ResolutionGroup cached = cache.get(
                artifact,
                request.isResolveManagedVersions(),

            VersionResult result) {
        Versioning versioning = null;
        try {
            if (metadata != null) {
                try (SyncContext syncContext = syncContextFactory.newInstance(session, true)) {
                    syncContext.acquire(null, Collections.singleton(metadata));

                    if (metadata.getPath() != null && Files.exists(metadata.getPath())) {