From 28bdc7ca8170d61060bc24c7d1d7c7ac5bd0b187 Mon Sep 17 00:00:00 2001
From: Aleksandr Nikolaev <aleksandr.nikolaev@jetbrains.com>
Date: Mon, 8 Sep 2025 17:41:29 +0200
Subject: [PATCH] Add annotation RequiredByIntellijPlugin to mark API used by
 Kotlin DataFrame IntelliJ Plugin. Mark such API in the library

---
 .../jetbrains/kotlinx/dataframe/ColumnsContainer.kt  |  3 +++
 .../org/jetbrains/kotlinx/dataframe/DataFrame.kt     |  3 +++
 .../org/jetbrains/kotlinx/dataframe/DataRow.kt       |  2 ++
 .../annotations/RequiredByIntellijPlugin.kt          | 12 ++++++++++++
 .../jetbrains/kotlinx/dataframe/api/DataFrameGet.kt  |  2 ++
 .../jetbrains/kotlinx/dataframe/api/DataRowApi.kt    |  4 ++++
 .../jetbrains/kotlinx/dataframe/api/generateCode.kt  |  3 +++
 .../org/jetbrains/kotlinx/dataframe/api/schema.kt    |  2 ++
 .../jetbrains/kotlinx/dataframe/api/valueCounts.kt   |  2 ++
 .../kotlinx/dataframe/columns/BaseColumn.kt          |  2 ++
 .../jetbrains/kotlinx/dataframe/impl/DebugUtil.kt    |  3 +++
 .../jetbrains/kotlinx/dataframe/impl/Rendering.kt    |  2 ++
 .../kotlinx/dataframe/impl/columns/DataColumnImpl.kt |  4 ++++
 .../dataframe/jupyter/DisableRowsLimitWrapper.kt     |  2 ++
 .../dataframe/jupyter/KotlinNotebookPluginUtils.kt   |  3 +++
 .../kotlinx/dataframe/io/JsonFacadeForDebugger.java  |  3 +++
 16 files changed, 52 insertions(+)
 create mode 100644 core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/RequiredByIntellijPlugin.kt

diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/ColumnsContainer.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/ColumnsContainer.kt
index 6f58c938ec..02d72ffe43 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/ColumnsContainer.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/ColumnsContainer.kt
@@ -1,6 +1,7 @@
 package org.jetbrains.kotlinx.dataframe
 
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.ColumnSelectionDsl
 import org.jetbrains.kotlinx.dataframe.api.asColumnGroup
 import org.jetbrains.kotlinx.dataframe.api.cast
@@ -26,8 +27,10 @@ public interface ColumnsContainer<out T> : ColumnsScope<T> {
 
     // region columns
 
+    @RequiredByIntellijPlugin
     public fun columns(): List<AnyCol>
 
+    @RequiredByIntellijPlugin
     public fun columnsCount(): Int
 
     public fun containsColumn(name: String): Boolean
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt
index c43bb4ee86..adff782b74 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataFrame.kt
@@ -6,6 +6,7 @@ import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
 import org.jetbrains.kotlinx.dataframe.annotations.HasSchema
 import org.jetbrains.kotlinx.dataframe.annotations.Interpretable
 import org.jetbrains.kotlinx.dataframe.annotations.Refine
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.ColumnsSelectionDsl
 import org.jetbrains.kotlinx.dataframe.api.add
 import org.jetbrains.kotlinx.dataframe.api.cast
@@ -73,6 +74,7 @@ public interface DataFrame<out T> :
      *
      * @return The number of rows in the [DataFrame].
      */
+    @RequiredByIntellijPlugin
     public fun rowsCount(): Int
 
     public operator fun iterator(): Iterator<DataRow<T>> = rows().iterator()
@@ -97,6 +99,7 @@ public interface DataFrame<out T> :
 
     // region get rows
 
+    @RequiredByIntellijPlugin
     public operator fun get(index: Int): DataRow<T>
 
     public operator fun get(indices: Iterable<Int>): DataFrame<T> = getRows(indices)
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataRow.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataRow.kt
index b89437c974..7c0a17c12f 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataRow.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataRow.kt
@@ -2,6 +2,7 @@ package org.jetbrains.kotlinx.dataframe
 
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
 import org.jetbrains.kotlinx.dataframe.annotations.HasSchema
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.next
 import org.jetbrains.kotlinx.dataframe.api.prev
 import org.jetbrains.kotlinx.dataframe.columns.ColumnKind
@@ -53,6 +54,7 @@ public interface DataRow<out T> {
 
     public operator fun get(path: ColumnPath): Any? = owner.get(path)[index]
 
+    @RequiredByIntellijPlugin
     public operator fun get(name: String): Any?
 
     public fun getColumnGroup(columnName: String): AnyRow {
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/RequiredByIntellijPlugin.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/RequiredByIntellijPlugin.kt
new file mode 100644
index 0000000000..a4ddcf35ab
--- /dev/null
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/RequiredByIntellijPlugin.kt
@@ -0,0 +1,12 @@
+package org.jetbrains.kotlinx.dataframe.annotations
+
+/**
+ * Marks API used by Kotlin DataFrame IntelliJ Plugin.
+ *
+ * Such API should remain stable:
+ * - It should not be moved, renamed, or removed.
+ * - The number of parameters and their types should not change.
+ *
+ * If changes to such API are required, they should first be supported in the Kotlin DataFrame IntelliJ Plugin.
+ */
+internal annotation class RequiredByIntellijPlugin
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataFrameGet.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataFrameGet.kt
index 23eca777a0..77bd83cf1e 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataFrameGet.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataFrameGet.kt
@@ -10,6 +10,7 @@ import org.jetbrains.kotlinx.dataframe.DataColumn
 import org.jetbrains.kotlinx.dataframe.DataFrame
 import org.jetbrains.kotlinx.dataframe.DataRow
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
 import org.jetbrains.kotlinx.dataframe.columns.ColumnPath
 import org.jetbrains.kotlinx.dataframe.columns.ColumnReference
@@ -167,6 +168,7 @@ public operator fun ColumnsContainer<*>.contains(column: KProperty<*>): Boolean
 
 // region rows
 
+@RequiredByIntellijPlugin
 public fun <T> DataFrame<T>.rows(): Iterable<DataRow<T>> =
     object : Iterable<DataRow<T>> {
         override fun iterator() =
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataRowApi.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataRowApi.kt
index 51e853be21..e3b63b4b48 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataRowApi.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/DataRowApi.kt
@@ -10,6 +10,7 @@ import org.jetbrains.kotlinx.dataframe.RowExpression
 import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
 import org.jetbrains.kotlinx.dataframe.annotations.CandidateForRemoval
 import org.jetbrains.kotlinx.dataframe.annotations.DataSchema
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.columns.ColumnReference
 import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.owner
@@ -32,6 +33,7 @@ public inline fun <reified R> AnyRow.valuesOf(): List<R> = values().filterIsInst
 
 // region DataSchema
 @DataSchema
+@RequiredByIntellijPlugin
 public data class NameValuePair<V>(val name: String, val value: V)
 
 // Without these overloads row.transpose().name or row.map { name } won't resolve
@@ -56,6 +58,7 @@ public val DataRow<NameValuePair<*>>.value: Any?
 public inline fun <reified R> AnyRow.namedValuesOf(): List<NameValuePair<R>> =
     values().zip(columnNames()).filter { it.first is R }.map { NameValuePair(it.second, it.first as R) }
 
+@RequiredByIntellijPlugin
 public fun AnyRow.namedValues(): List<NameValuePair<Any?>> =
     values().zip(columnNames()) { value, name -> NameValuePair(name, value) }
 
@@ -172,6 +175,7 @@ public inline fun <T> DataRow<T>.diffOrNull(expression: RowExpression<T, Long>):
 public inline fun <T> DataRow<T>.diffOrNull(expression: RowExpression<T, Float>): Float? =
     prev()?.let { p -> expression(this, this) - expression(p, p) }
 
+@RequiredByIntellijPlugin
 public fun AnyRow.columnsCount(): Int = df().ncol
 
 public fun AnyRow.columnNames(): List<String> = df().columnNames()
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt
index a9b5380fa1..cfc96719a5 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt
@@ -3,6 +3,7 @@ package org.jetbrains.kotlinx.dataframe.api
 import org.jetbrains.kotlinx.dataframe.DataFrame
 import org.jetbrains.kotlinx.dataframe.annotations.ColumnName
 import org.jetbrains.kotlinx.dataframe.annotations.DataSchema
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.codeGen.CodeGenerator
 import org.jetbrains.kotlinx.dataframe.codeGen.MarkerVisibility
 import org.jetbrains.kotlinx.dataframe.codeGen.NameNormalizer
@@ -268,6 +269,7 @@ public val NameNormalizer.Companion.default: NameNormalizer get() = NameNormaliz
  * @see CodeString.print
  */
 @JvmInline
+@RequiredByIntellijPlugin
 public value class CodeString(public val value: String) {
     override fun toString(): String = value
 }
@@ -327,6 +329,7 @@ public inline fun <reified T> DataFrame<T>.generateCode(
     replaceWith = ReplaceWith(GENERATE_CODE_REPLACE2),
     level = DeprecationLevel.WARNING,
 )
+@RequiredByIntellijPlugin
 public fun <T> DataFrame<T>.generateCode(
     markerName: String,
     fields: Boolean = true,
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/schema.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/schema.kt
index d8b665bd82..6b058d7446 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/schema.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/schema.kt
@@ -3,6 +3,7 @@ package org.jetbrains.kotlinx.dataframe.api
 import org.jetbrains.kotlinx.dataframe.AnyFrame
 import org.jetbrains.kotlinx.dataframe.AnyRow
 import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.impl.api.compileTimeSchemaImpl
 import org.jetbrains.kotlinx.dataframe.impl.owner
 import org.jetbrains.kotlinx.dataframe.impl.schema.extractSchema
@@ -16,6 +17,7 @@ public fun AnyRow.schema(): DataFrameSchema = owner.schema()
 
 // region DataFrame
 
+@RequiredByIntellijPlugin
 public fun AnyFrame.schema(): DataFrameSchema = extractSchema()
 
 // endregion
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/valueCounts.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/valueCounts.kt
index d1e7475206..5a49c050a0 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/valueCounts.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/valueCounts.kt
@@ -8,6 +8,7 @@ import org.jetbrains.kotlinx.dataframe.annotations.AccessApiOverload
 import org.jetbrains.kotlinx.dataframe.annotations.DataSchema
 import org.jetbrains.kotlinx.dataframe.annotations.Interpretable
 import org.jetbrains.kotlinx.dataframe.annotations.Refine
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.columns.toColumnSet
 import org.jetbrains.kotlinx.dataframe.impl.nameGenerator
 import org.jetbrains.kotlinx.dataframe.util.DEPRECATED_ACCESS_API
@@ -28,6 +29,7 @@ public interface ValueCount {
 
 internal val defaultCountColumnName: String = ValueCount::count.name
 
+@RequiredByIntellijPlugin
 public fun <T> DataColumn<T>.valueCounts(
     sort: Boolean = true,
     ascending: Boolean = false,
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/columns/BaseColumn.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/columns/BaseColumn.kt
index 7a4bf00e3e..2285addb95 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/columns/BaseColumn.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/columns/BaseColumn.kt
@@ -4,6 +4,7 @@ import org.jetbrains.kotlinx.dataframe.AnyBaseCol
 import org.jetbrains.kotlinx.dataframe.AnyCol
 import org.jetbrains.kotlinx.dataframe.AnyRow
 import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.ColumnsSelectionDsl
 import org.jetbrains.kotlinx.dataframe.impl.asList
 import org.jetbrains.kotlinx.dataframe.impl.columnName
@@ -82,6 +83,7 @@ public interface BaseColumn<out T> : ColumnReference<T> {
 
     public fun values(): Iterable<T>
 
+    @RequiredByIntellijPlugin
     public fun toList(): List<T> = values().asList()
 
     public fun toSet(): Set<T>
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/DebugUtil.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/DebugUtil.kt
index 8dff717592..cbaa3f7574 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/DebugUtil.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/DebugUtil.kt
@@ -2,16 +2,19 @@ package org.jetbrains.kotlinx.dataframe.impl
 
 import org.jetbrains.kotlinx.dataframe.AnyFrame
 import org.jetbrains.kotlinx.dataframe.DataFrame
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.ValueCount
 import org.jetbrains.kotlinx.dataframe.api.count
 import org.jetbrains.kotlinx.dataframe.api.map
 
 // Needed to attach an expanded node with lazily evaluated expressions to DataFrame debug view
 @Suppress("unused")
+@RequiredByIntellijPlugin
 internal class Info(val df: AnyFrame)
 
 internal class Counts(val value: Any?, val count: Int) {
     override fun toString(): String = "$value -> $count"
 }
 
+@RequiredByIntellijPlugin
 internal fun DataFrame<ValueCount>.render(): List<Counts> = map { Counts(it[0], it.count) }
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/Rendering.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/Rendering.kt
index fa382f5454..1771cd49b3 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/Rendering.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/Rendering.kt
@@ -4,6 +4,7 @@ import kotlinx.datetime.LocalDateTime
 import kotlinx.datetime.LocalTime
 import org.jetbrains.kotlinx.dataframe.AnyCol
 import org.jetbrains.kotlinx.dataframe.AnyFrame
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.asColumnGroup
 import org.jetbrains.kotlinx.dataframe.api.asDataFrame
 import org.jetbrains.kotlinx.dataframe.columns.ColumnKind
@@ -54,6 +55,7 @@ internal fun renderType(column: ColumnSchema) =
         else -> throw NotImplementedError()
     }
 
+@RequiredByIntellijPlugin
 internal fun renderType(type: KType?): String {
     return when (type?.classifier) {
         null -> "*"
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/DataColumnImpl.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/DataColumnImpl.kt
index cdc6eaae77..b511009259 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/DataColumnImpl.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/DataColumnImpl.kt
@@ -2,6 +2,7 @@ package org.jetbrains.kotlinx.dataframe.impl.columns
 
 import org.jetbrains.kotlinx.dataframe.BuildConfig
 import org.jetbrains.kotlinx.dataframe.DataColumn
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.dataFrameOf
 import org.jetbrains.kotlinx.dataframe.impl.isArray
 import org.jetbrains.kotlinx.dataframe.impl.isPrimitiveArray
@@ -50,10 +51,13 @@ internal abstract class DataColumnImpl<T>(
 
     protected val distinct = distinct ?: lazy { values.toSet() }
 
+    @RequiredByIntellijPlugin
     override fun name() = name
 
+    @RequiredByIntellijPlugin
     override fun values() = values
 
+    @RequiredByIntellijPlugin
     override fun type() = type
 
     override fun toSet() = distinct.value
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/DisableRowsLimitWrapper.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/DisableRowsLimitWrapper.kt
index 68bd3d9abc..715d94a86a 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/DisableRowsLimitWrapper.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/DisableRowsLimitWrapper.kt
@@ -1,8 +1,10 @@
 package org.jetbrains.kotlinx.dataframe.jupyter
 
 import org.jetbrains.kotlinx.dataframe.AnyFrame
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 
 /**
  * Allows for disabling the rows limit when generating a DISPLAY output in Jupyter.
  */
+@RequiredByIntellijPlugin
 public data class DisableRowsLimitWrapper(public val value: AnyFrame)
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/KotlinNotebookPluginUtils.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/KotlinNotebookPluginUtils.kt
index de150fd644..238f3712eb 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/KotlinNotebookPluginUtils.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/jupyter/KotlinNotebookPluginUtils.kt
@@ -4,6 +4,7 @@ import org.jetbrains.kotlinx.dataframe.AnyCol
 import org.jetbrains.kotlinx.dataframe.AnyFrame
 import org.jetbrains.kotlinx.dataframe.AnyRow
 import org.jetbrains.kotlinx.dataframe.DataRow
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin
 import org.jetbrains.kotlinx.dataframe.api.Convert
 import org.jetbrains.kotlinx.dataframe.api.FormatClause
 import org.jetbrains.kotlinx.dataframe.api.FormattedFrame
@@ -50,6 +51,7 @@ public object KotlinNotebookPluginUtils {
      * Returns a subset of rows from the given dataframe for rendering.
      * It's used for example for dynamic pagination in Kotlin Notebook Plugin.
      */
+    @RequiredByIntellijPlugin
     public fun getRowsSubsetForRendering(dataFrameLike: Any?, startIdx: Int, endIdx: Int): DisableRowsLimitWrapper =
         when (dataFrameLike) {
             null -> throw IllegalArgumentException("Dataframe is null")
@@ -76,6 +78,7 @@ public object KotlinNotebookPluginUtils {
      *
      * @return The sorted dataframe.
      */
+    @RequiredByIntellijPlugin
     public fun sortByColumns(dataFrameLike: Any?, columnPaths: List<List<String>>, desc: List<Boolean>): AnyFrame =
         when (dataFrameLike) {
             null -> throw IllegalArgumentException("Dataframe is null")
diff --git a/dataframe-json/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/JsonFacadeForDebugger.java b/dataframe-json/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/JsonFacadeForDebugger.java
index 2e4112daee..a9b6976337 100644
--- a/dataframe-json/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/JsonFacadeForDebugger.java
+++ b/dataframe-json/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/JsonFacadeForDebugger.java
@@ -1,6 +1,8 @@
 package org.jetbrains.kotlinx.dataframe.io;
 
 import org.jetbrains.kotlinx.dataframe.DataFrame;
+import org.jetbrains.kotlinx.dataframe.annotations.RequiredByIntellijPlugin;
+
 import java.util.Collections;
 
 class JsonFacadeForDebugger {
@@ -10,6 +12,7 @@ class JsonFacadeForDebugger {
      * DO NOT BREAK ABI OF THIS METHOD!!
      * Keep it for backward compatibility, create a new method if signature must change
      */
+    @RequiredByIntellijPlugin
     static String convertToJson(DataFrame<?> df, int rowLimit, Integer nestedRowLimit) {
         return JsonKt.toJsonWithMetadata(df, rowLimit, nestedRowLimit, false, Collections.emptyList(), false);
     }