Compatibility with Groovy 2.5

[dawidsawa]

Perhaps due to some @Immutable AST transformation changes in Groovy 2.5, some methods are failing now.

Grgit.open().head() fails with the following:

Caught: java.lang.RuntimeException: Unsupported type (org.ajoberstar.grgit.Person) found for field 'author' while constructing immutable class org.ajoberstar.grgit.Commit.
Immutable classes only support properties with effectively immutable types including:
- Strings, primitive types, wrapper types, Class, BigInteger and BigDecimal, enums
- classes annotated with @KnownImmutable and known immutables (java.awt.Color, java.net.URI)
- Cloneable classes, collections, maps and arrays, and other classes with special handling
  (java.util.Date and various java.time.* classes and interfaces)
Other restrictions apply, please see the groovydoc for ImmutableOptions for further details
java.lang.RuntimeException: Unsupported type (org.ajoberstar.grgit.Person) found for field 'author' while constructing immutable class org.ajoberstar.grgit.Commit.
Immutable classes only support properties with effectively immutable types including:
- Strings, primitive types, wrapper types, Class, BigInteger and BigDecimal, enums
- classes annotated with @KnownImmutable and known immutables (java.awt.Color, java.net.URI)
- Cloneable classes, collections, maps and arrays, and other classes with special handling
  (java.util.Date and various java.time.* classes and interfaces)
Other restrictions apply, please see the groovydoc for ImmutableOptions for further details
        at org.ajoberstar.grgit.Commit.<init>(Commit.groovy)
        at org.ajoberstar.grgit.util.JGitUtil.convertCommit(JGitUtil.groovy:134)
        at org.ajoberstar.grgit.util.JGitUtil$convertCommit$2.callStatic(Unknown Source)
        at org.ajoberstar.grgit.util.JGitUtil.resolveCommit(JGitUtil.groovy:109)
        at org.ajoberstar.grgit.util.JGitUtil$resolveCommit$1.callStatic(Unknown Source)
        at org.ajoberstar.grgit.util.JGitUtil.resolveCommit(JGitUtil.groovy:98)
        at org.ajoberstar.grgit.util.JGitUtil$resolveCommit$0.call(Unknown Source)
        at org.ajoberstar.grgit.service.ResolveService.toCommit(ResolveService.groovy:93)
        at org.ajoberstar.grgit.service.ResolveService$toCommit.call(Unknown Source)
        at org.ajoberstar.grgit.Grgit.head(Grgit.groovy:153)
        at org.ajoberstar.grgit.Grgit$head$0.call(Unknown Source)

Grgit.open().branch.getCurrent() fails with the following:

Caught: java.lang.RuntimeException: Unsupported type (org.ajoberstar.grgit.Branch) found for field 'trackingBranch' while constructing immutable class org.ajoberstar.grgit.Branch.
Immutable classes only support properties with effectively immutable types including:
- Strings, primitive types, wrapper types, Class, BigInteger and BigDecimal, enums
- classes annotated with @KnownImmutable and known immutables (java.awt.Color, java.net.URI)
- Cloneable classes, collections, maps and arrays, and other classes with special handling
  (java.util.Date and various java.time.* classes and interfaces)
Other restrictions apply, please see the groovydoc for ImmutableOptions for further details
java.lang.RuntimeException: Unsupported type (org.ajoberstar.grgit.Branch) found for field 'trackingBranch' while constructing immutable class org.ajoberstar.grgit.Branch.
Immutable classes only support properties with effectively immutable types including:
- Strings, primitive types, wrapper types, Class, BigInteger and BigDecimal, enums
- classes annotated with @KnownImmutable and known immutables (java.awt.Color, java.net.URI)
- Cloneable classes, collections, maps and arrays, and other classes with special handling
  (java.util.Date and various java.time.* classes and interfaces)
Other restrictions apply, please see the groovydoc for ImmutableOptions for further details
        at org.ajoberstar.grgit.Branch.<init>(Branch.groovy)
        at org.ajoberstar.grgit.util.JGitUtil.resolveBranch(JGitUtil.groovy:209)
        at org.ajoberstar.grgit.util.JGitUtil$resolveBranch.call(Unknown Source)
        at org.ajoberstar.grgit.service.BranchService.current(BranchService.groovy:60)
        at org.ajoberstar.grgit.service.BranchService.getCurrent(BranchService.groovy:70)
        at org.ajoberstar.grgit.service.BranchService$getCurrent.call(Unknown Source)

[ajoberstar]

Thanks for the report, I'll get this fixed in the next release.