[c-dilks]

We expect to see no change here. Note that 6.2-SNAPSHOT is a different major version 6 than the one upstream. I call the version on code.jlab.org as 5.99.0, and it is effectively the same as our 6.2-SNAPHOT from clasweb.

The details get confusing, but this PR should cause no change here!

• 5.99.0 release notes: https://code.jlab.org/hallb/evio/-/releases/v5.99.0
• details: https://code.jlab.org/dilks/jarchaeology-evio

For redundancy and hopefully clarity, here is a copy of those details below:

What is 5.99.0??

It's an attempt to reproduce 6.2-SNAPSHOT from clasweb/clas12maven
from our forked evio repo source code.

Based on comparing the decompiled 6.2-SNAPSHOT JAR and the source code history, I find that:

• the 6.2-SNAPSHOT JAR was deployed on 23 December 2020
• looking at the commit DAG in this region, and comparing to the decompiled 6.2-SNAPSHOT JAR, I find that this JAR must have been:
  • produced from commit d5694f57 or sometime later, since this commit added CompactReaderTest.java method main333
  • produced from commit b72af6e4 or sometime earlier, since this is the last commit where RecordViewer.java was present
• there are no relevant changes to the Java code between these commits (d5694f57..b72af6e4), other than minor changes such as @Deprecated decorators
• therefore, I've branched off the latest commit in this range, b72af6e4 and added a CI config, updated the POM file, and added a settings.xml file, all for package-registry deployment
• I named this version as 5.99.0, since:
  • the first tag after b72af6e4 is v6.0.0 (and it's even a number that's semantically later than that of the 6.2-SNAPSHOT JAR)
  • there are no versions on clasweb of jevio with major version 5 (skips from 4.4 to 6.2-SNAPSHOT, the 6.2-SNAPSHOT JAR)
  • let's avoid simply calling it 6.2, since the current latest tag in the source code repo is 6.2.1, which includes about 5 years of changes beyond the 6.2-SNAPSHOT JAR version

Differences between 6.2-SNAPSHOT and 5.99.0

In summary:

• The only real difference is the Java version used to build:
  • 6.2-SNAPSHOT used Java 7
  • 5.99.0 uses Java 8 (since OpenJDK 21 dropped support for Java 7)
• The decompiled JAR files appear to be consistent

Detailed details are given in the following sections.

Java Versions

Looking at the manifests, we have:

>>> unzip -p jevio-6.2-SNAPSHOT.jar META-INF/MANIFEST.MF
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Built-By: baltzell
Created-By: Apache Maven 3.5.0
Build-Jdk: 1.8.0_31

>>> unzip -p jevio-5.99.0.jar META-INF/MANIFEST.MF
Manifest-Version: 1.0
Created-By: Maven JAR Plugin 3.5.1
Java-Version: 8
Build-Jdk-Spec: 21

Inspecting a class within, we have:

>>> javap -v -cp jevio-6.2-SNAPSHOT.jar org.jlab.coda.jevio.CompositeData | grep "major version"
  major version: 51

>>> javap -v -cp jevio-5.99.0.jar org.jlab.coda.jevio.CompositeData | grep "major version"
  major version: 52

So, 6.2-SNAPSHOT was built with Java 7, whereas 5.99.0 was built with Java 8.

JAR file contents

jar tf of the 6.2-SNAPSHOT JAR includes the following line, which the 5.99.0 JAR does not have:

org/jlab/coda/jevio/DataType$1.class

CFR Decompilation

To compare decompilations, clone this repo and run

git diff 6.2-SNAPSHOT..5.99.0

These are tags for the 6.2-SNAPSHOT and 5.99.0 JAR decompilations, respectively.

• the only differences between the uber jars are scoped to jevio only, so the dependencies in the uber JAR are exactly the same between 6.2-SNAPSHOT and 5.99.0.
• in hipo/WriterMT.java
  • version 6.2-SNAPSHOT:

    WriterMT.this.writerBytesWritten = WriterMT.this.writerBytesWritten + (long)bytesToWrite;

  • version 5.99.0:

    WriterMT.this.writerBytesWritten += bytesToWrite;

  • bytesToWrite is an int, and the cast to long is gone; since writerBytesWritten is long, and long is wider than int, these should behave the same
• in jevio/BaseStructure.java:
  • version 6.2-SNAPSHOT:

    public Enumeration<?> children() {

  • version 5.99.0:

    @Override
    public Enumeration<? extends TreeNode> children() {

  • this was a necessary fix for Java 8
• jevio/CompositeData.java shows what appear to be non-trivial differences
  • the 6.2-SNAPSHOT has CFR placeholders (e.g., void var9_16)
  • Claude says the differences are purely cosmetic and both decompiled versions follow the logic of the original source code
  • it is highly likely that these cosmetic differences are a result from the 6.2-SNAPSHOT version being built with major version 51 (i.e., Java 7)
    and the 5.99.0 version being built with major version 52 (Java 8)
  • I tried rebuilding 5.99.0 with Java 7 (and OpenJDK 11), and decompiling that, but I get the same thing I get with Java 8
• jevio/DataType.java seems to show differences in some switch statements, but they are indeed the same; details:
  • the 6.2-SNAPSHOT version uses enumerator names, whereas the 5.99.0 version uses enumerator numbers (ordinals)
  • version 6.2-SNAPSHOT, with the enumerator ordinal numbers added by me as comments (note: CFR strips comments); case statements are sorted by ordinal number:

    public boolean isStructure() {
        switch (this) {
            case TAGSEGMENT:  // 12
            case ALSOSEGMENT: // 13
            case ALSOBANK:    // 14
            case BANK:        // 16
            case SEGMENT:     // 17 // NOTE: the enum value itself is 32 (0x20), but it's the 18th enum constant declared, i.e., ordinal 17
            {
                return true;
            }
        }
        return false;
    }
    
    public boolean isInteger() {
        switch (this) {
            case UINT32:   // 1
            case SHORT16:  // 4
            case USHORT16: // 5
            case CHAR8:    // 6
            case UCHAR8:   // 7
            case LONG64:   // 9
            case ULONG64:  // 10
            case INT32:    // 11
            {
                return true;
            }
        }
        return false;
    }

  • version 5.99.0, with the enumerator names added by me as comments:

    public boolean isStructure() {
        switch (this.ordinal()) {
            case 12: // TAGSEGMENT
            case 13: // ALSOSEGMENT
            case 14: // ALSOBANK
            case 16: // BANK
            case 17: // SEGMENT // NOTE: the enum value itself is 32 (0x20)
            {
                return true;
            }
        }
        return false;
    }
    
    public boolean isInteger() {
        switch (this.ordinal()) {
            case 1:  // UINT32
            case 4:  // SHORT16
            case 5:  // USHORT16
            case 6:  // CHAR8
            case 7:  // UCHAR8
            case 9:  // LONG64
            case 10: // ULONG64
            case 11: // INT32
            {
                return true;
            }
        }
        return false;
    }

• inconsequential differences:
  • several added @Deprecated decorators
  • exception variables are named differently
  • string concatenation