feat(compile-hlo)!: strict-by-default conversion errors, indexSelect routing, createBasic parity (#1247)

CHANGELOG.md

@@ -2,6 +2,29 @@
 
 ## [Unreleased]
 
+### Changed
+
+- **StableHLO conversion fails loudly by default**
+  ([#1247](https://github.com/SKaiNET-developers/SKaiNET/issues/1247)): converter failures were
+  MLIR comments — a graph whose first node failed to lower could cascade through every downstream
+  node and still "succeed" with an empty `return` and exit 0. `StableHloConverter` and every
+  `StableHloConverterFactory` entry point now take a `ConversionErrorPolicy` (default `STRICT`):
+  an unconvertible node throws `HloConversionException`, and an operand whose producer was never
+  converted throws `MissingOperandException` instead of being silently dropped and shifting later
+  operands into earlier positions. `ConversionErrorPolicy.LENIENT` restores the historical
+  comment-and-continue behavior for callers that inspect partially-converted modules.
+
+### Fixed
+
+- **`indexSelect` is now routable in the StableHLO gather converter**
+  ([#1247](https://github.com/SKaiNET-developers/SKaiNET/issues/1247)): the KSP tracing wrapper
+  emits `indexSelect`, but the registry only knew `index_select`, so traced index-select nodes
+  (e.g. Gemma per-layer embeddings) could not lower. Both spellings route to the gather lowering.
+- **`StableHloConverterFactory.createBasic` registers `NeuralNetOperationsConverter`**
+  ([#1247](https://github.com/SKaiNET-developers/SKaiNET/issues/1247)): parity with
+  `createExtended` — a traced model with conv/pool/norm nodes no longer fails to lower via the
+  basic factory, with registration order preserving existing op-name precedence.
+
 ## [0.52.0] - 2026-09-01
 
 Headline: **the engine stops silently running on the scalar floor.** A downstream Gemma 4 port

skainet-compile/skainet-compile-hlo/api/jvm/skainet-compile-hlo.api

@@ -47,14 +47,16 @@ public final class sk/ainet/compile/hlo/ConversionContext {
 	public fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)V
 	public fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;)V
 	public fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;)V
-	public synthetic fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)V
+	public synthetic fun <init> (Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun clear ()V
 	public final fun emitComment (Ljava/lang/String;)V
 	public final fun emitEncodingAnnotation (Ljava/lang/String;ILsk/ainet/lang/tensor/ops/TensorSpec;)V
 	public final fun emitLine (Ljava/lang/String;)V
 	public final fun emitModuleDeclaration (Ljava/lang/String;)V
 	public final fun emitOperation (Ljava/lang/String;)V
 	public final fun getContent ()Ljava/lang/String;
+	public final fun getErrorPolicy ()Lsk/ainet/compile/hlo/ConversionErrorPolicy;
 	public final fun getExternalParameters ()Ljava/util/List;
 	public final fun getGranularity ()Lsk/ainet/compile/target/OpGranularityPolicy;
 	public final fun getInputNodes (Lsk/ainet/lang/graph/GraphNode;)Ljava/util/List;
@@ -74,6 +76,14 @@ public final class sk/ainet/compile/hlo/ConversionContext {
 	public final fun setValueType (Ljava/lang/String;Ljava/lang/String;)V
 }
 
+public final class sk/ainet/compile/hlo/ConversionErrorPolicy : java/lang/Enum {
+	public static final field LENIENT Lsk/ainet/compile/hlo/ConversionErrorPolicy;
+	public static final field STRICT Lsk/ainet/compile/hlo/ConversionErrorPolicy;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public static fun valueOf (Ljava/lang/String;)Lsk/ainet/compile/hlo/ConversionErrorPolicy;
+	public static fun values ()[Lsk/ainet/compile/hlo/ConversionErrorPolicy;
+}
+
 public abstract class sk/ainet/compile/hlo/ConversionResult {
 }
 
@@ -153,6 +163,20 @@ public final class sk/ainet/compile/hlo/ExternalParameterRef {
 	public fun toString ()Ljava/lang/String;
 }
 
+public final class sk/ainet/compile/hlo/HloConversionException : java/lang/IllegalStateException {
+	public fun <init> (Ljava/lang/String;Ljava/lang/Throwable;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/Throwable;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+}
+
+public final class sk/ainet/compile/hlo/MissingOperandException : java/lang/IllegalStateException {
+	public fun <init> (Ljava/lang/String;Ljava/lang/String;ILjava/lang/String;I)V
+	public final fun getInputPort ()I
+	public final fun getNodeId ()Ljava/lang/String;
+	public final fun getOpName ()Ljava/lang/String;
+	public final fun getSourceNodeId ()Ljava/lang/String;
+	public final fun getSourceOutputPort ()I
+}
+
 public final class sk/ainet/compile/hlo/MlirValidator {
 	public fun <init> ()V
 	public final fun validate (Ljava/lang/String;)Ljava/util/List;
@@ -189,7 +213,8 @@ public final class sk/ainet/compile/hlo/StableHloConverter {
 	public fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)V
 	public fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;)V
 	public fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;)V
-	public synthetic fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)V
+	public synthetic fun <init> (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun convert (Lsk/ainet/lang/graph/ComputeGraph;Ljava/lang/String;)Lsk/ainet/compile/hlo/StableHloModule;
 	public static synthetic fun convert$default (Lsk/ainet/compile/hlo/StableHloConverter;Lsk/ainet/lang/graph/ComputeGraph;Ljava/lang/String;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloModule;
 	public final fun convertWithOptimization (Lsk/ainet/lang/graph/ComputeGraph;Lsk/ainet/compile/hlo/StableHloOptimizer;)Lsk/ainet/compile/hlo/StableHloModule;
@@ -201,18 +226,22 @@ public final class sk/ainet/compile/hlo/StableHloConverterFactory {
 	public static final fun createBasic (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createBasic (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createBasic (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
-	public static synthetic fun createBasic$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static final fun createBasic (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static synthetic fun createBasic$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Ljava/lang/String;Lsk/ainet/compile/target/OpGranularityPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createCustom (Lsk/ainet/compile/hlo/StableHloOperationRegistry;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createCustom (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createCustom (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createCustom (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
-	public static synthetic fun createCustom$default (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static final fun createCustom (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static synthetic fun createCustom$default (Lsk/ainet/compile/hlo/StableHloOperationRegistry;Lsk/ainet/compile/hlo/TypeMapper;Lsk/ainet/compile/hlo/MlirValidator;Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createExtended ()Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createExtended (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
-	public static synthetic fun createExtended$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static final fun createExtended (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static synthetic fun createExtended$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createFast ()Lsk/ainet/compile/hlo/StableHloConverter;
 	public static final fun createFast (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
-	public static synthetic fun createFast$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static final fun createFast (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;)Lsk/ainet/compile/hlo/StableHloConverter;
+	public static synthetic fun createFast$default (Lsk/ainet/compile/hlo/ConstantMaterializationPolicy;Lsk/ainet/compile/hlo/ConversionErrorPolicy;ILjava/lang/Object;)Lsk/ainet/compile/hlo/StableHloConverter;
 }
 
 public final class sk/ainet/compile/hlo/StableHloExportArchitecture {

skainet-compile/skainet-compile-hlo/src/commonMain/kotlin/sk/ainet/compile/hlo/ConversionContext.kt

@@ -35,7 +35,13 @@ public class ConversionContext @kotlin.jvm.JvmOverloads constructor(
      * caller from the [sk.ainet.compile.opt.TargetOptimizers] registry and passed in;
      * `null` = decompose everything (portable default). The emitter only *reads* it.
      */
-    public val granularity: sk.ainet.compile.target.OpGranularityPolicy? = null
+    public val granularity: sk.ainet.compile.target.OpGranularityPolicy? = null,
+    /**
+     * How operand-resolution failures behave: [ConversionErrorPolicy.STRICT]
+     * (default) throws [MissingOperandException]; [ConversionErrorPolicy.LENIENT]
+     * reproduces the historical silent-drop (see issue #1247).
+     */
+    public val errorPolicy: ConversionErrorPolicy = ConversionErrorPolicy.STRICT
 ) {
     private val valueNames = mutableMapOf<String, String>()
     private val valueTypes = mutableMapOf<String, String>()
@@ -78,10 +84,24 @@ public class ConversionContext @kotlin.jvm.JvmOverloads constructor(
      */
     public fun resolveOperands(node: GraphNode): List<String> {
         val g = graph ?: return emptyList()
-        return g.edges
+        val incoming = g.edges
             .filter { it.destination.id == node.id }
             .sortedBy { it.destinationInputIndex }
-            .mapNotNull { getValueName(it.source.id, it.sourceOutputIndex) }
+        if (errorPolicy == ConversionErrorPolicy.LENIENT) {
+            // Historical behavior: unresolved operands are dropped, and later
+            // operands slide into earlier positional slots (issue #1247).
+            return incoming.mapNotNull { getValueName(it.source.id, it.sourceOutputIndex) }
+        }
+        return incoming.map { edge ->
+            getValueName(edge.source.id, edge.sourceOutputIndex)
+                ?: throw MissingOperandException(
+                    nodeId = node.id,
+                    opName = node.operation.name,
+                    inputPort = edge.destinationInputIndex,
+                    sourceNodeId = edge.source.id,
+                    sourceOutputPort = edge.sourceOutputIndex,
+                )
+        }
     }
 
     /**

skainet-compile/skainet-compile-hlo/src/commonMain/kotlin/sk/ainet/compile/hlo/ConversionErrorPolicy.kt

@@ -0,0 +1,53 @@
+package sk.ainet.compile.hlo
+
+/**
+ * Governs how the converter reacts when a node cannot be lowered.
+ *
+ * Historically every failure was emitted as an MLIR comment and conversion
+ * continued, so a broken graph could produce a compute-free module that
+ * still "succeeded" (empty `return`, exit 0) — see issue #1247, where an
+ * operand-linkage failure at the first node cascaded through 1000+ nodes
+ * silently. [STRICT] makes any conversion failure a thrown exception;
+ * [LENIENT] preserves the historical comment-and-continue behavior for
+ * callers that diff or inspect partially-converted modules.
+ */
+public enum class ConversionErrorPolicy {
+    /** Any node that fails to convert aborts the conversion with an exception. Default. */
+    STRICT,
+
+    /** Failures become MLIR comments and conversion continues (pre-#1247 behavior). */
+    LENIENT,
+}
+
+/**
+ * A node's input operand could not be resolved to an SSA value — its
+ * producer was never converted (or was converted under a different name).
+ *
+ * Thrown by [ConversionContext.resolveOperands] under
+ * [ConversionErrorPolicy.STRICT] instead of silently dropping the operand,
+ * which both hid the failure and shifted later operands into earlier
+ * positional slots (issue #1247: a gather whose weight operand failed saw
+ * its indices operand slide into slot 0).
+ */
+public class MissingOperandException(
+    public val nodeId: String,
+    public val opName: String,
+    public val inputPort: Int,
+    public val sourceNodeId: String,
+    public val sourceOutputPort: Int,
+) : IllegalStateException(
+    "Node '$nodeId' (op '$opName') has no SSA value for input port $inputPort: " +
+        "producer node '$sourceNodeId' (output port $sourceOutputPort) was never " +
+        "successfully converted. Under ConversionErrorPolicy.LENIENT this operand " +
+        "would be silently dropped, shifting later operands into earlier slots."
+)
+
+/**
+ * A node failed to lower to StableHLO under [ConversionErrorPolicy.STRICT].
+ * Carries the same diagnostic text the LENIENT mode would have emitted as
+ * an MLIR comment, plus the causing exception when one was thrown.
+ */
+public class HloConversionException(
+    message: String,
+    cause: Throwable? = null,
+) : IllegalStateException(message, cause)