Set<Attribute<?>> extraAttributes = new LinkedHashSet<>();
        for (ImmutableAttributes attributes : candidateAttributeSets) {
            extraAttributes.addAll(attributes.keySet());
        }
        removeSameAttributes(requested, extraAttributes);
        Attribute<?>[] extraAttributesArray = extraAttributes.toArray(new Attribute<?>[0]);

    }

    @Override
    public ImmutableMap<NamespaceId, String> getExtraAttributes() {
        return extraAttributes;
    }

    @Override
    public void setExtraAttributes(Map<NamespaceId, String> extraAttributes) {
        this.extraAttributes = ImmutableMap.copyOf(extraAttributes);
    }

    @Nullable
    @Override
    public String getBranch() {
        return branch;
    }

        ]
        AttributeContainer requested = attribute(attr1, "v3")

        when:
        def extraAttributes = schema.collectExtraAttributes(candidates, requested).toList()

        then:
        extraAttributes.contains(attr2)
        extraAttributes.contains(attr3)
        !extraAttributes.contains(attr1)
    }

    def "prefers extra attributes from the selection schema"() {

        requested {
            attribute(attr1, "v3")
        }

        when:
        collectExtraAttributes()

        then:
        extraAttributes.isEmpty()
    }

    private boolean hasExtraAttribute(Attribute<?> attribute) {
        extraAttributes.contains(attribute)
    }

    private boolean doesNotHaveExtraAttribute(Attribute<?> attribute) {
        !hasExtraAttribute(attribute)
    }

        return createModuleRevisionId(org, name, branch, rev, extraAttributes, true);
    }

    public static ModuleRevisionId createModuleRevisionId(String org, String name, String branch, String revConstraint, Map<String, String> extraAttributes, boolean replaceNullBranchWithDefault) {
        synchronized (MODULE_ID_LOCK) {

        }

        Attribute<?>[] extraAttributes = schema.collectExtraAttributes(candidateAttributeSets, requested);
        if (remaining.cardinality() > 1) {
            disambiguateWithExtraAttributes(extraAttributes);
        }
        if (remaining.cardinality() > 1) {
            disambiguateWithRequestedAttributeKeys(extraAttributes);
        }

        this.branch = metadata.branch;
        this.artifactDefinitions = metadata.artifactDefinitions;
        this.dependencies = metadata.dependencies;
        this.excludes = metadata.excludes;
        this.extraAttributes = metadata.extraAttributes;

        copyCachedState(metadata, metadata.getVariantDerivationStrategy() != variantDerivationStrategy);
    }

        this.artifactDefinitions = metadata.artifactDefinitions;
        this.dependencies = metadata.dependencies;
        this.excludes = metadata.excludes;
        this.extraAttributes = metadata.extraAttributes;
        this.metadata = metadata.metadata;
    }

    RealisedIvyModuleResolveMetadata(
        DefaultIvyModuleResolveMetadata metadata,

    @Override
    IvyModule withNoIvyMetaData() {
        metadataPublish = MetadataPublish.GRADLE
        return this
    }

    IvyFileModule withExtraAttributes(Map extraAttributes) {
        this.extraAttributes.putAll(extraAttributes)
        return this
    }

    /**
     * Keys in extra info will be prefixed with namespace prefix "ns" in this fixture.
     */

            Map<String, String> extraAttributes = getExtraAttributes(attributes, ignoredAttNames);
            for (String name : extraAttributes.keySet()) {
                item.setExtraAttribute(name, extraAttributes.get(name));
            }
        }

        private PatternMatcher getMatcher(String matcherName) {