fixing same issue for extension generation by ksp with test

Author: Jolanrensen

plugins/symbol-processor/src/main/kotlin/org/jetbrains/dataframe/ksp/ExtensionsGenerator.kt

@@ -12,7 +12,6 @@ import com.google.devtools.ksp.symbol.KSClassifierReference
 import com.google.devtools.ksp.symbol.KSDeclaration
 import com.google.devtools.ksp.symbol.KSFile
 import com.google.devtools.ksp.symbol.KSName
-import com.google.devtools.ksp.symbol.KSPropertyDeclaration
 import com.google.devtools.ksp.symbol.KSTypeReference
 import com.google.devtools.ksp.symbol.KSValueArgument
 import com.google.devtools.ksp.symbol.Modifier
@@ -61,11 +60,10 @@ class ExtensionsGenerator(
         return when {
             isClassOrInterface() && effectivelyPublicOrInternal() -> {
                 DataSchemaDeclaration(
-                    this,
-                    declarations
-                        .filterIsInstance<KSPropertyDeclaration>()
+                    origin = this,
+                    properties = getAllProperties()
                         .map { KSAnnotatedWithType(it, it.simpleName, it.type) }
-                        .toList()
+                        .toList(),
                 )
             }
             else -> null

plugins/symbol-processor/src/test/kotlin/org/jetbrains/dataframe/ksp/DataFrameSymbolProcessorTest.kt

@@ -748,6 +748,37 @@ class DataFrameSymbolProcessorTest {
         result.successfulCompilation shouldBe true
     }
 
+    @Test
+    fun `generic interface as supertype`() {
+        val result = KspCompilationTestRunner.compile(
+            TestCompilationParameters(
+                sources = listOf(
+                    SourceFile.kotlin(
+                        "MySources.kt",
+                        """
+                package org.example
+
+                $imports
+
+                interface KeyValue<T> {
+                    val key: String
+                    val value: T
+                }
+                
+                @DataSchema
+                interface MySchema : KeyValue<Int>
+
+
+                val ColumnsContainer<MySchema>.test1: DataColumn<String> get() = key
+                val DataRow<MySchema>.test2: Int get() = value
+                        """.trimIndent()
+                    )
+                )
+            )
+        )
+        result.successfulCompilation shouldBe true
+    }
+
     @Test
     fun `nested interface`() {
         val result = KspCompilationTestRunner.compile(