1 files changed, 22 insertions, 3 deletions

diff --git a/src/cuchaz/enigma/mapping/ClassMapping.java b/src/cuchaz/enigma/mapping/ClassMapping.java
index c7f930c..5936512 100644
--- a/src/cuchaz/enigma/mapping/ClassMapping.java
+++ b/src/cuchaz/enigma/mapping/ClassMapping.java
@@ -129,10 +129,18 @@ public class ClassMapping implements Serializable, Comparable<ClassMapping>
         
         protected void addFieldMapping( FieldMapping fieldMapping )
         {
+                if( m_fieldsByObf.containsKey( fieldMapping.getObfName() ) )
+                {
+                        throw new Error( "Already have mapping for " + m_obfName + "." + fieldMapping.getObfName() );
+                }
+                if( m_fieldsByDeobf.containsKey( fieldMapping.getDeobfName() ) )
+                {
+                        throw new Error( "Already have mapping for " + m_deobfName + "." + fieldMapping.getDeobfName() );
+                }
                 m_fieldsByObf.put( fieldMapping.getObfName(), fieldMapping );
                 m_fieldsByDeobf.put( fieldMapping.getDeobfName(), fieldMapping );
+                assert( m_fieldsByObf.size() == m_fieldsByDeobf.size() );
         }
-        
 
         public String getObfFieldName( String deobfName )
         {
@@ -179,8 +187,19 @@ public class ClassMapping implements Serializable, Comparable<ClassMapping>
         
         protected void addMethodMapping( MethodMapping methodMapping )
         {
-                m_methodsByObf.put( getMethodKey( methodMapping.getObfName(), methodMapping.getObfSignature() ), methodMapping );
-                m_methodsByDeobf.put( getMethodKey( methodMapping.getDeobfName(), methodMapping.getDeobfSignature() ), methodMapping );
+                String obfKey = getMethodKey( methodMapping.getObfName(), methodMapping.getObfSignature() );
+                String deobfKey = getMethodKey( methodMapping.getDeobfName(), methodMapping.getDeobfSignature() );
+                if( m_methodsByObf.containsKey( obfKey ) )
+                {
+                        throw new Error( "Already have mapping for " + m_obfName + "." + obfKey );
+                }
+                if( m_methodsByDeobf.containsKey( deobfKey ) )
+                {
+                        throw new Error( "Already have mapping for " + m_deobfName + "." + deobfKey );
+                }
+                m_methodsByObf.put( obfKey, methodMapping );
+                m_methodsByDeobf.put( deobfKey, methodMapping );
+                assert( m_methodsByObf.size() == m_methodsByDeobf.size() );
         }
         
         public MethodMapping getMethodByObf( String obfName, String signature )