Maven Cache Extension - Restore /target artifacts not working?

Question

I am currently introducing the Maven Build Cache Extension to a large project (EAR, multiple WARS, multiple JAR modules) to speed up build times.

https://maven.apache.org/extensions/maven-build-cache-extension/index.html

Pretty much standard (no customization) works perfectly fine for this build - since there is not that much special logic with plugins:

.mvn/extensions.xml

<extension>
    <groupId>org.apache.maven.extensions</groupId>
    <artifactId>maven-build-cache-extension</artifactId>
    <version>1.1.0</version>
</extension>

.mvn/maven-build-cache-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<cache xmlns="http://maven.apache.org/BUILD-CACHE-CONFIG/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://maven.apache.org/BUILD-CACHE-CONFIG/1.0.0 https://maven.apache.org/xsd/build-cache-config-1.0.0.xsd">

    <configuration>
        <enabled>true</enabled>
        <hashAlgorithm>XX</hashAlgorithm>
        <projectVersioning adjustMetaInf="false"/>
        <local>
            <maxBuildsCached>5</maxBuildsCached>
        </local>
        <multiModule>
            <discovery>
                <scanProfiles>
                    <scanProfile>full</scanProfile>
                </scanProfiles>
            </discovery>
        </multiModule>
    </configuration>

    <input>
        <global>
            <glob>*</glob>
            <includes>
                <include>src/</include>
            </includes>
        </global>
    </input>
</cache>

QUESTION

Caching of modules and builds works fine, but restoring the main build artifact(s) in /target/ not. When I do a mvn clean package, the target build dirs are ofcourse deleted, but the main artifact (JAR, EAR, WARs) are not restored to /target.

Why are artifacts not restored to /target ?

I see output like this, which suggests that a restore should happen?

[INFO] Going to calculate checksum for project [groupId=com.xxx, artifactId=aaa]
[INFO] Going to calculate checksum for project [groupId=com.xxx, artifactId=bbb]
[INFO] Going to calculate checksum for project [groupId=com.xxx, artifactId=ccc]
[INFO] Project inputs calculated in 71 ms. XX checksum [fae782eba5969b98] calculated in 62 ms.
[INFO] Attempting to restore project com.xxx:yyy from build cache
[INFO] Local build found by checksum fae782eba5969b98
[INFO] Found cached build, restoring com.xxx:yyy from cache by checksum fae782eba5969b98

Answer 1

It turns out to be a bug in all current versions (1.0.0 - 1.1.0): MBUILDCACHE-67

The next release (1.1.1-SNAPSHOT) fixes this problem.