Add debug property for ambiguous Ruby to Java calls. Fixes #4894.

headius · headius · commit d8198d9b3f25 · 2018-03-19T17:04:42.000-05:00
diff --git a/core/src/main/java/org/jruby/java/dispatch/CallableSelector.java b/core/src/main/java/org/jruby/java/dispatch/CallableSelector.java
@@ -22,6 +22,7 @@
 import org.jruby.javasupport.JavaUtil;
 import org.jruby.javasupport.ParameterTypes;
 import org.jruby.runtime.builtin.IRubyObject;
+import org.jruby.util.cli.Options;
 import org.jruby.util.collections.IntHashMap;
 import static org.jruby.util.CodegenUtils.getBoxType;
 import static org.jruby.util.CodegenUtils.prettyParams;
@@ -279,7 +280,18 @@ else if ( procArity < 0 && methodArity >= -(procArity + 1) ) { // *splat that fi
                 method = mostSpecific;
 
                 if ( ambiguous ) {
-                    runtime.getWarnings().warn("ambiguous Java methods found, using " + ((Member) ((JavaCallable) method).accessibleObject()).getName() + prettyParams(msTypes));
+                    if (Options.DEBUG_AMBIGUOUS_JAVA_CALLS.load()) {
+                        runtime.newRuntimeError(
+                                "multiple Java methods found, dumping backtrace and choosing "
+                                        + ((Member) ((JavaCallable) method).accessibleObject()).getName()
+                                        + prettyParams(msTypes)
+                        ).printStackTrace(runtime.getErr());
+                    } else {
+                        runtime.getWarnings().warn(
+                                "multiple Java methods found, use -Xdebug.ambiguous.java.calls for backtrace. Choosing "
+                                        + ((Member) ((JavaCallable) method).accessibleObject()).getName()
+                                        + prettyParams(msTypes));
+                    }
                 }
             }
         }
diff --git a/core/src/main/java/org/jruby/util/cli/Options.java b/core/src/main/java/org/jruby/util/cli/Options.java
@@ -188,6 +188,7 @@ public class Options {
     public static final Option<String> LOGGER_CLASS = string(DEBUG, "logger.class", new String[]{"class name"}, "org.jruby.util.log.StandardErrorLogger", "Use specified class for logging.");
     public static final Option<Boolean> DUMP_INSTANCE_VARS = bool(DEBUG, "dump.variables", false, "Dump class + instance var names on first new of Object subclasses.");
     public static final Option<Boolean> REWRITE_JAVA_TRACE = bool(DEBUG, "rewrite.java.trace", true, "Rewrite stack traces from exceptions raised in Java calls.");
+    public static final Option<Boolean> DEBUG_AMBIGUOUS_JAVA_CALLS = bool(DEBUG, "debug.ambiguous.java.calls", false, "Toggle verbose reporting of all ambiguous calls to Java objects");
 
     // TODO: Replace flag that's false on 9 with proper module checks
     public static final Option<Boolean> JI_SETACCESSIBLE = bool(JAVA_INTEGRATION, "ji.setAccessible", calculateSetAccessibleDefault(), "Try to set inaccessible Java methods to be accessible.");
