[MLIR][Transform] Return empty handles when the included sequence fails (llvm#169782)

This fixes a bug in the interpreter for transform.include op, which
crashes when attempting to copy out the handles from the yield op of a
failing sequence.

Author: alexdura-inceptron

mlir/lib/Dialect/Transform/IR/TransformOps.cpp

@@ -2062,6 +2062,10 @@ transform::IncludeOp::apply(transform::TransformRewriter &rewriter,
 
   DiagnosedSilenceableFailure result = applySequenceBlock(
       callee.getBody().front(), getFailurePropagationMode(), state, results);
+
+  if (!result.succeeded())
+    return result;
+
   mappings.clear();
   detail::prepareValueMappings(
       mappings, callee.getBody().front().getTerminator()->getOperands(), state);

mlir/test/Dialect/Transform/include-failure-propagation.mlir

@@ -0,0 +1,38 @@
+// RUN: mlir-opt %s --transform-interpreter -allow-unregistered-dialect --verify-diagnostics
+
+module attributes { transform.with_named_sequence } {
+  // Callee returns a silenceable failure when given a module instead of func.func.
+  transform.named_sequence @callee(%root: !transform.any_op {transform.consumed}) -> (!transform.any_op) {
+    transform.test_consume_operand_of_op_kind_or_fail %root, "func.func" : !transform.any_op
+    transform.yield %root : !transform.any_op
+  }
+
+  transform.named_sequence @__transform_main(%root: !transform.any_op) {
+    %res = transform.sequence %root : !transform.any_op -> !transform.any_op failures(suppress) {
+    ^bb0(%arg0: !transform.any_op):
+      // This include returns a silenceable failure; it must not remap results.
+      %included = transform.include @callee failures(propagate) (%arg0) : (!transform.any_op) -> (!transform.any_op)
+      transform.yield %included : !transform.any_op
+    }
+
+    %count = transform.num_associations %res : (!transform.any_op) -> !transform.param<i64>
+    // expected-remark @below {{0}}
+    transform.debug.emit_param_as_remark %count : !transform.param<i64>
+
+    // If the include incorrectly forwarded mappings on failure, this would run
+    // and produce an unexpected remark under --verify-diagnostics.
+    transform.foreach %res : !transform.any_op {
+    ^bb0(%it: !transform.any_op):
+      transform.debug.emit_remark_at %it, "include result unexpectedly populated" : !transform.any_op
+    }
+    transform.yield
+  }
+}
+
+// -----
+
+module {
+  func.func @payload() {
+    return
+  }
+}