It is not possible to override the default java.util.Map handler

[whilo]

In Clojure code:

(get
 (TransitFactory/writeHandlerMap {java.util.Map "foo bar"})
 java.util.Map)

yields the default map handler unchanged instead of an exception (which happens for java.util.List). This behavior worked with transit-clj 0.8.285. I have been using this for https://github.com/replikativ/incognito/ to serialize all unknown record types as special maps including tag information. Unfortunately the default-handler does not cover this case, because it is only triggered if the thing is unknown, while records are treated as maps by default.

[puredanger]

Could you use the clojure.lang.IRecord marker type to catch these?

[whilo]

I get a java.lang.RuntimeException: java.lang.RuntimeException: More thane one match for class ... from the checkBaseInterfaces method in WriteHandlerMap in this case.

[whilo]

The full stacktrace is:

  WriteHandlerMap.java:  226  com.cognitect.transit.impl.WriteHandlerMap/checkBaseInterfaces
  WriteHandlerMap.java:  195  com.cognitect.transit.impl.WriteHandlerMap/getHandler
  AbstractEmitter.java:  199  com.cognitect.transit.impl.AbstractEmitter/marshalTop
      JsonEmitter.java:   41  com.cognitect.transit.impl.JsonEmitter/emit
    WriterFactory.java:   62  com.cognitect.transit.impl.WriterFactory$1/write
           transit.clj:  171  cognitect.transit/write
           transit.clj:  168  cognitect.transit/write
                  REPL:   31  incognito.transit-test/fn/fn
                  REPL:   20  incognito.transit-test/fn
                  REPL:   13  incognito.transit-test/fn
              test.clj:  203  cider.nrepl.middleware.test/test-var/fn
              test.clj:  203  cider.nrepl.middleware.test/test-var
              test.clj:  195  cider.nrepl.middleware.test/test-var
              test.clj:  218  cider.nrepl.middleware.test/test-vars/fn/fn
              test.clj:  687  clojure.test/default-fixture
              test.clj:  683  clojure.test/default-fixture
              test.clj:  218  cider.nrepl.middleware.test/test-vars/fn
              test.clj:  687  clojure.test/default-fixture
              test.clj:  683  clojure.test/default-fixture
              test.clj:  215  cider.nrepl.middleware.test/test-vars
              test.clj:  209  cider.nrepl.middleware.test/test-vars
              test.clj:  231  cider.nrepl.middleware.test/test-ns
              test.clj:  222  cider.nrepl.middleware.test/test-ns
              test.clj:  242  cider.nrepl.middleware.test/test-var-query
              test.clj:  235  cider.nrepl.middleware.test/test-var-query
              test.clj:  280  cider.nrepl.middleware.test/handle-test-var-query-op/fn/fn
              AFn.java:  152  clojure.lang.AFn/applyToHelper
              AFn.java:  144  clojure.lang.AFn/applyTo
              core.clj:  665  clojure.core/apply
              core.clj: 1973  clojure.core/with-bindings*
              core.clj: 1973  clojure.core/with-bindings*
           RestFn.java:  425  clojure.lang.RestFn/invoke
              test.clj:  272  cider.nrepl.middleware.test/handle-test-var-query-op/fn
              AFn.java:   22  clojure.lang.AFn/run
           session.clj:  171  nrepl.middleware.session/session-exec/main-loop/fn
           session.clj:  170  nrepl.middleware.session/session-exec/main-loop
              AFn.java:   22  clojure.lang.AFn/run
           Thread.java:  830  java.lang.Thread/run

[whilo]

Looking at the commit log the MapHandler has changed at some point, caching was also introduced in the meantime. I can try to track down why it is shadowed, if this is helpful.