Binary incompatibility in JavaHL runtime version check

[Philip Martin]

JavaHL uses JNI to load Subversion shared libraries and it includes a
runtime version check to ensure that the loaded library is the right
version.  A program built with 1.8 would report an error if it loaded
1.7 at runtime.  It seems we have introduced a binary incompatibility in
1.9 that causes the JVM to SEGV rather than report an error.

A simple Java program:

$ cat xx.java
import org.apache.subversion.javahl.*;
public class xx {
  public static void main(String argv[]) {
    System.out.println("hello");
    ISVNRepos repos = new SVNRepos();
  }
};

Build with 1.8 and run with 1.7:

$ javac -g -extdirs /usr/local/subversion-1.8/lib/svn-javahl xx.java
$ java -Djava.library.path=/usr/local/subversion-1.7/lib -cp 
/usr/local/subversion-1.8/lib/svn-javahl/svn-javahl.jar:. xx
hello
Exception in thread "main" java.lang.LinkageError: Native library version must 
be at least 1.8.0, but is only 1.7.23-dev (under development)
        at 
org.apache.subversion.javahl.NativeResources.init(NativeResources.java:136)
        at 
org.apache.subversion.javahl.NativeResources.loadNativeLibrary(NativeResources.java:99)
        at org.apache.subversion.javahl.SVNRepos.<clinit>(SVNRepos.java:46)
        at xx.main(xx.java:5)

Build with 1.9 and run with 1.8:

$ javac -g -extdirs /usr/local/subversion/lib/svn-javahl xx.java
$ java -Djava.library.path=/usr/local/subversion-1.8/lib -cp 
/usr/local/subversion/lib/svn-javahl/svn-javahl.jar:. xx
hello
Aborted

The stack trace shows:

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C  [libapr-1.so.0+0x27b54]  apr_threadkey_private_get+0x4

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j  org.apache.subversion.javahl.types.Version.getMajor()I+0
j  org.apache.subversion.javahl.types.Version.isAtLeast(III)Z+1
j  org.apache.subversion.javahl.NativeResources.init()V+17
j  org.apache.subversion.javahl.NativeResources.loadNativeLibrary()V+71
j  org.apache.subversion.javahl.types.Version.<clinit>()V+0

-- 
Philip Martin
WANdisco