From b8fbf3d5f95d40863e5e15e19f13421fbba7fa78 Mon Sep 17 00:00:00 2001
From: jonathan343 <jonathangee09@gmail.com>
Date: Wed, 22 Oct 2025 12:55:21 -0400
Subject: [PATCH 1/2] Increment member index on skipped member

---
 .../smithy/python/codegen/generators/StructureGenerator.java     | 1 +
 1 file changed, 1 insertion(+)

diff --git a/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java b/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
index 492e032a9..a418384f4 100644
--- a/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
+++ b/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
@@ -425,6 +425,7 @@ private void deserializeMembers(Collection<MemberShape> members) {
         for (MemberShape member : members) {
             var target = model.expectShape(member.getTarget());
             if (target.hasTrait(StreamingTrait.class) && target.isUnionShape()) {
+                index++;
                 continue;
             }
             writer.write("""

From 26c742fa1176010e13e60d7b6693704024d88319 Mon Sep 17 00:00:00 2001
From: jonathan343 <jonathangee09@gmail.com>
Date: Thu, 23 Oct 2025 14:33:05 -0400
Subject: [PATCH 2/2] increment once at the start of the loop

---
 .../python/codegen/generators/StructureGenerator.java       | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java b/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
index a418384f4..1cfa9c2cf 100644
--- a/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
+++ b/codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java
@@ -421,18 +421,18 @@ def _consumer(schema: Schema, de: ShapeDeserializer) -> None:
     }
 
     private void deserializeMembers(Collection<MemberShape> members) {
-        int index = 0;
+        int index = -1;
         for (MemberShape member : members) {
+            index++;
             var target = model.expectShape(member.getTarget());
             if (target.hasTrait(StreamingTrait.class) && target.isUnionShape()) {
-                index++;
                 continue;
             }
             writer.write("""
                     case $L:
                         kwargs[$S] = ${C|}
                     """,
-                    index++,
+                    index,
                     symbolProvider.toMemberName(member),
                     writer.consumer(
                             w -> target.accept(new MemberDeserializerGenerator(context, writer, member, "de"))));