[MSHADE-406] relocated multi-release classes aren't moved to a new directory

**[Brian Gruber](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=bgruber-datadog)** opened **[MSHADE-406](https://issues.apache.org/jira/browse/MSHADE-406?redirect=false)** and commented

In a project in which a dependency has a multi-release jar, classes that match a relocation pattern and are in the `META-INF/versions` directories are not moved to the new directory structure. They are, however, rewritten so that the class file itself specifies the new package name.

Sample project: https://gist.github.com/bgruber/5fb045759505da5150d3e93ec5c6010e

The generated jar file still contains classes like this:

```java
$ jar tf target/relocation-test-SNAPSHOT-1.0.jar | grep versions | head
META-INF/versions/
META-INF/versions/9/
META-INF/versions/9/org/
META-INF/versions/9/org/bouncycastle/
META-INF/versions/9/org/bouncycastle/crypto/
META-INF/versions/9/org/bouncycastle/crypto/AsymmetricCipherKeyPair.class
META-INF/versions/9/org/bouncycastle/crypto/Digest.class
META-INF/versions/9/org/bouncycastle/crypto/CryptoServicesRegistrar$Property.class
META-INF/versions/9/org/bouncycastle/crypto/CryptoServicesRegistrar.class
META-INF/versions/9/org/bouncycastle/crypto/KeyGenerationParameters.class
```

I expect these class files to be under `META-INF/versions/9/com/dd/org/bouncycastle`. Extracting one of them from the jar and examining it, the class file does appear to have been modified to have the new package name:

```java
$ jar xf target/relocation-test-SNAPSHOT-1.0.jar META-INF/versions/9/org/bouncycastle/crypto/Digest.class
$ javap META-INF/versions/9/org/bouncycastle/crypto/Digest.class
Compiled from "Digest.java"
public interface com.dd.org.bouncycastle.crypto.Digest {
public abstract java.lang.String getAlgorithmName();
public abstract int getDigestSize();
public abstract void update(byte);
public abstract void update(byte[], int, int);
public abstract int doFinal(byte[], int);
public abstract void reset();
}
```

---

**Issue Links:**
- [PHOENIX-7011](https://issues.apache.org/jira/browse/PHOENIX-7011) Remove relocated multi-release classes from shaded artifacts
(_**"causes"**_)

**Remote Links:**
- [GitHub Pull Request #202
](https://github.com/apache/maven-shade-plugin/pull/202)

4 votes, 5 watchers

Start with the linked sample project and reproduce the shaded JAR, then inspect how relocation handles classes under META-INF/versions. Compare the generated paths with the expected META-INF/versions/9/com/dd/org/bouncycastle layout and verify with javap that the relocated class names remain correct.

Written by the indexing model from the issue text.