validate field name duplicates at least sometimes

firmware/integration/rusefi_config.txt

@@ -2104,4 +2104,5 @@ end_struct
 #define show_test_presets true
 #define show_Frankenso_presets true
 
+
 ! poke

java_tools/configuration_definition/src/main/java/com/rusefi/ConfigStructure.java

@@ -1,7 +1,11 @@
 package com.rusefi;
 
+import com.fathzer.soft.javaluator.Parameters;
+
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import static com.rusefi.ConfigField.BOOLEAN_T;
 
@@ -30,6 +34,7 @@ public class ConfigStructure {
     public final BitState readingBitState = new BitState();
 
     private ConfigField cPrevField = ConfigField.VOID;
+    private final Set<String> names = new HashSet<>();
 
     public ConfigStructure(String name, String comment, boolean withPrefix, boolean withConstructor) {
         this.name = name;
@@ -82,10 +87,14 @@ public class ConfigStructure {
     }
 
     public void addC(ConfigField cf) {
-        // skip duplicate names
+        // skip duplicate names - that's the weird use-case of conditional project definition like lambdaTable
         if (cf.getName().equals(cPrevField.getName()))
             return;
 
+        boolean isNew = names.add(cf.getName());
+        if (!isNew)
+            throw new IllegalStateException(cf.getName() + " name already used");
+
         cFields.add(cf);
 
         cPrevField = cf;

java_tools/configuration_definition/src/main/java/com/rusefi/ReaderState.java

@@ -33,7 +33,6 @@ public class ReaderState {
 
     public EnumsReader enumsReader = new EnumsReader();
 
-
     private static void handleBitLine(ReaderState state, String line) {
         line = line.substring(BIT.length() + 1).trim();
 

java_tools/configuration_definition/src/main/java/com/rusefi/test/ConfigFieldParserTest.java

@@ -48,6 +48,24 @@ public class ConfigFieldParserTest {
                 "; total TS size = 8\n", new String(writer.toCharArray()));
     }
 
+    @Test(expected = IllegalStateException.class)
+    public void testSameFieldTwice() throws IOException {
+        String test = "struct pid_s\n" +
+                "int afr_type1;PID dTime;\"ms\",      1,      0,       0, 3000,      0\n" +
+                "int afr_type2;PID dTime;\"ms\",      1,      0,       0, 3000,      0\n" +
+                "int afr_type1;PID dTime;\"ms\",      1,      0,       0, 3000,      0\n" +
+                "end_struct\n";
+        ReaderState state = new ReaderState();
+        BufferedReader reader = new BufferedReader(new StringReader(test));
+
+        BaseCHeaderConsumer consumer = new BaseCHeaderConsumer() {
+            @Override
+            public void endFile() {
+            }
+        };
+        state.readBufferedReader(reader, Arrays.asList(consumer));
+    }
+
     @Test
     public void testCustomEnum() throws IOException {
         String test = "struct pid_s\n" +