Revert code where ColumnSchema.equals was accidental to original matches semantic

Author: koperagen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/codeGen/SchemaProcessorImpl.kt

@@ -91,7 +91,7 @@ internal class SchemaProcessorImpl(
             val superFields = requiredSuperMarkers.mapNotNull { it.getField(columnName) }
 
             val fieldsToOverride = superFields
-                .filter { it.columnSchema != columnSchema }
+                .filter { !it.columnSchema.compare(columnSchema).matches() }
                 .map { it.fieldName }
                 .distinctBy { it.unquoted }
 

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/codeGen/ReplCodeGenTests.kt

@@ -1,14 +1,17 @@
 package org.jetbrains.kotlinx.dataframe.codeGen
 
 import io.kotest.matchers.shouldBe
+import io.kotest.matchers.string.shouldContain
 import io.kotest.matchers.string.shouldNotBeEmpty
+import io.kotest.matchers.string.shouldNotContain
 import org.jetbrains.kotlinx.dataframe.AnyRow
 import org.jetbrains.kotlinx.dataframe.ColumnsScope
 import org.jetbrains.kotlinx.dataframe.DataColumn
 import org.jetbrains.kotlinx.dataframe.DataRow
 import org.jetbrains.kotlinx.dataframe.annotations.DataSchema
 import org.jetbrains.kotlinx.dataframe.api.add
 import org.jetbrains.kotlinx.dataframe.api.asFrame
+import org.jetbrains.kotlinx.dataframe.api.columnOf
 import org.jetbrains.kotlinx.dataframe.api.convert
 import org.jetbrains.kotlinx.dataframe.api.dataFrameOf
 import org.jetbrains.kotlinx.dataframe.api.filter
@@ -300,4 +303,39 @@ class ReplCodeGenTests : BaseTest() {
             val $dfRowName<_DataFrameType2>.leaf: $dfRowName<_DataFrameType3> @JvmName("_DataFrameType2_leaf") get() = this["leaf"] as $dfRowName<_DataFrameType3>
             """.trimIndent()
     }
+
+    object TestColumnOrderInGroup {
+        @DataSchema
+        interface Nested {
+            val x: Int
+            val y: String
+        }
+
+        @DataSchema
+        interface Base {
+            val nested: Nested
+            val extra: Int?
+        }
+
+        val df = dataFrameOf(
+            "nested" to columnOf(
+                "y" to columnOf("hello"),
+                "x" to columnOf(42),
+            ),
+            "extra" to columnOf(1),
+        )
+    }
+
+    @Test
+    fun `column order in nested group should not cause override`() {
+        val repl = ReplCodeGenerator.create()
+        repl.process<TestColumnOrderInGroup.Nested>()
+        repl.process<TestColumnOrderInGroup.Base>()
+        val c = repl.process(TestColumnOrderInGroup.df)
+
+        // extra: Int? → Int — valid
+        c.declarations shouldContain "override val extra"
+        // nested: Group{y,x} vs Group{x,y} — semantically the same, no need to override
+        c.declarations shouldNotContain "override val nested"
+    }
 }