From 8d2397afadb67cc6b4f1775397f7dfd7be88dd8f Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:24:14 -0700
Subject: [PATCH 01/15] be more precise about allocated part size

---
 include/aws/s3/private/s3_request.h | 15 +++++++++++----
 source/s3_auto_ranged_put.c         |  4 ++++
 source/s3_client.c                  |  2 +-
 source/s3_request.c                 |  5 +++++
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/include/aws/s3/private/s3_request.h b/include/aws/s3/private/s3_request.h
index 33776b001..26573b52a 100644
--- a/include/aws/s3/private/s3_request.h
+++ b/include/aws/s3/private/s3_request.h
@@ -166,14 +166,17 @@ struct aws_s3_request {
      */
     struct aws_s3_buffer_ticket *ticket;
 
-    /* Beginning range of this part. */
-    /* TODO currently only used by auto_range_get, could be hooked up to auto_range_put as well. */
+    /* Beginning range of this part.  */
     uint64_t part_range_start;
 
-    /* Last byte of this part.*/
-    /* TODO currently only used by auto_range_get, could be hooked up to auto_range_put as well. */
+    /* Last byte of this part.
+     * Note: this is available on both put and get, but in put case it can be optimistic,
+     * ex for unknown content length we dont know what the end will be until we finish reading data. */
     uint64_t part_range_end;
 
+    /* Number of bytes in this part. */
+    uint64_t part_size;
+
     /* Part number that this request refers to.  If this is not a part, this can be 0.  (S3 Part Numbers start at 1.)
      * However, must currently be a valid part number (ie: greater than 0) if the response body is to be streamed to the
      * caller.
@@ -292,6 +295,10 @@ struct aws_s3_request *aws_s3_request_new(
     uint32_t part_number,
     uint32_t flags);
 
+/* Sets part boundary information on the request. */
+AWS_S3_API
+void aws_s3_request_set_part_boundary(struct aws_s3_request *request, uint64_t part_start, uint64_t part_end);
+
 /* Set up the request to be sent. Called each time before the request is sent. Will initially call
  * aws_s3_request_clean_up_send_data to clear out anything previously existing in send_data. */
 AWS_S3_API
diff --git a/source/s3_auto_ranged_put.c b/source/s3_auto_ranged_put.c
index 0c11315fe..d39e2e014 100644
--- a/source/s3_auto_ranged_put.c
+++ b/source/s3_auto_ranged_put.c
@@ -592,6 +592,10 @@ static bool s_s3_auto_ranged_put_update(
 
                 request->part_number = auto_ranged_put->threaded_update_data.next_part_number;
 
+                size_t request_body_size =
+                    s_compute_request_body_size(meta_request, request->part_number, &request->part_range_start);
+                request->part_range_end = request->part_range_start + request_body_size - 1;
+
                 /* If request was previously uploaded, we prepare it to ensure checksums still match,
                  * but ultimately it gets marked no-op and we don't send it */
                 request->was_previously_uploaded = request_previously_uploaded;
diff --git a/source/s3_client.c b/source/s3_client.c
index be97b9b88..4cdf776b0 100644
--- a/source/s3_client.c
+++ b/source/s3_client.c
@@ -1908,7 +1908,7 @@ void s_acquire_mem_and_prepare_request(
         struct aws_s3_buffer_pool_reserve_meta meta = {
             .client = client,
             .meta_request = meta_request,
-            .size = meta_request->part_size,
+            .size = aws_s3_request_get_part_size(request),
         };
 
         struct aws_s3_reserve_memory_payload *payload =
diff --git a/source/s3_request.c b/source/s3_request.c
index fa7cd83ba..78792568e 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -45,6 +45,11 @@ struct aws_s3_request *aws_s3_request_new(
     return request;
 }
 
+uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
+    /* +1 cause range end is inclusive */
+    return request->part_range_end - request->part_range_start + 1;
+}
+
 static void s_populate_metrics_from_message(struct aws_s3_request *request, struct aws_http_message *message) {
     struct aws_byte_cursor out_path;
     AWS_ZERO_STRUCT(out_path);

From 2bfdabb1028a316524e2a7e1bee98d24311abe91 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:29:27 -0700
Subject: [PATCH 02/15] add fallback

---
 include/aws/s3/private/s3_request.h | 3 ---
 source/s3_client.c                  | 1 +
 source/s3_request.c                 | 3 ++-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/aws/s3/private/s3_request.h b/include/aws/s3/private/s3_request.h
index 26573b52a..c160ff11a 100644
--- a/include/aws/s3/private/s3_request.h
+++ b/include/aws/s3/private/s3_request.h
@@ -174,9 +174,6 @@ struct aws_s3_request {
      * ex for unknown content length we dont know what the end will be until we finish reading data. */
     uint64_t part_range_end;
 
-    /* Number of bytes in this part. */
-    uint64_t part_size;
-
     /* Part number that this request refers to.  If this is not a part, this can be 0.  (S3 Part Numbers start at 1.)
      * However, must currently be a valid part number (ie: greater than 0) if the response body is to be streamed to the
      * caller.
diff --git a/source/s3_client.c b/source/s3_client.c
index 4cdf776b0..d25d30dc6 100644
--- a/source/s3_client.c
+++ b/source/s3_client.c
@@ -1905,6 +1905,7 @@ void s_acquire_mem_and_prepare_request(
 
         struct aws_allocator *allocator = request->allocator;
         struct aws_s3_meta_request *meta_request = request->meta_request;
+
         struct aws_s3_buffer_pool_reserve_meta meta = {
             .client = client,
             .meta_request = meta_request,
diff --git a/source/s3_request.c b/source/s3_request.c
index 78792568e..b993b0769 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -47,7 +47,8 @@ struct aws_s3_request *aws_s3_request_new(
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
     /* +1 cause range end is inclusive */
-    return request->part_range_end - request->part_range_start + 1;
+    uint64_t size = request->part_range_end - request->part_range_start + 1
+    return size > 0 ? size ? : request->meta_request->part_size;
 }
 
 static void s_populate_metrics_from_message(struct aws_s3_request *request, struct aws_http_message *message) {

From 120087dd29da13109f3958308b66d9fd0b052728 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:36:56 -0700
Subject: [PATCH 03/15] mobe helper earlier

---
 source/s3_auto_ranged_put.c | 56 ++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/source/s3_auto_ranged_put.c b/source/s3_auto_ranged_put.c
index d39e2e014..be5d7a352 100644
--- a/source/s3_auto_ranged_put.c
+++ b/source/s3_auto_ranged_put.c
@@ -322,6 +322,34 @@ static struct aws_s3_meta_request_vtable s_s3_auto_ranged_put_vtable = {
     .pause = s_s3_auto_ranged_put_pause,
 };
 
+/**
+ * Helper to compute request body size.
+ * Basically returns either part size or if content is not equally divisible into parts, the size of the remaining last
+ * part.
+ */
+static size_t s_compute_request_body_size(
+    const struct aws_s3_meta_request *meta_request,
+    uint32_t part_number,
+    uint64_t *offset_out) {
+    AWS_PRECONDITION(meta_request);
+
+    const struct aws_s3_auto_ranged_put *auto_ranged_put = meta_request->impl;
+
+    size_t request_body_size = meta_request->part_size;
+    /* Last part--adjust size to match remaining content length. */
+    if (auto_ranged_put->has_content_length && part_number == auto_ranged_put->total_num_parts_from_content_length) {
+        size_t content_remainder = (size_t)(auto_ranged_put->content_length % (uint64_t)meta_request->part_size);
+
+        if (content_remainder > 0) {
+            request_body_size = content_remainder;
+        }
+    }
+    /* The part_number starts at 1 */
+    *offset_out = (part_number - 1) * meta_request->part_size;
+
+    return request_body_size;
+}
+
 /* Allocate a new auto-ranged put meta request */
 struct aws_s3_meta_request *aws_s3_meta_request_auto_ranged_put_new(
     struct aws_allocator *allocator,
@@ -752,34 +780,6 @@ static bool s_s3_auto_ranged_put_update(
     return work_remaining;
 }
 
-/**
- * Helper to compute request body size.
- * Basically returns either part size or if content is not equally divisible into parts, the size of the remaining last
- * part.
- */
-static size_t s_compute_request_body_size(
-    const struct aws_s3_meta_request *meta_request,
-    uint32_t part_number,
-    uint64_t *offset_out) {
-    AWS_PRECONDITION(meta_request);
-
-    const struct aws_s3_auto_ranged_put *auto_ranged_put = meta_request->impl;
-
-    size_t request_body_size = meta_request->part_size;
-    /* Last part--adjust size to match remaining content length. */
-    if (auto_ranged_put->has_content_length && part_number == auto_ranged_put->total_num_parts_from_content_length) {
-        size_t content_remainder = (size_t)(auto_ranged_put->content_length % (uint64_t)meta_request->part_size);
-
-        if (content_remainder > 0) {
-            request_body_size = content_remainder;
-        }
-    }
-    /* The part_number starts at 1 */
-    *offset_out = (part_number - 1) * meta_request->part_size;
-
-    return request_body_size;
-}
-
 static int s_verify_part_matches_checksum(
     struct aws_allocator *allocator,
     struct aws_byte_cursor body_cur,

From 594d76856154e05bf726cb81d698bdd3118383b2 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:41:12 -0700
Subject: [PATCH 04/15] missing header

---
 source/s3_client.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/source/s3_client.c b/source/s3_client.c
index d25d30dc6..c48979bfd 100644
--- a/source/s3_client.c
+++ b/source/s3_client.c
@@ -11,6 +11,7 @@
 #include "aws/s3/private/s3_default_meta_request.h"
 #include "aws/s3/private/s3_meta_request_impl.h"
 #include "aws/s3/private/s3_parallel_input_stream.h"
+#include "aws/s3/private/s3_request.h"
 #include "aws/s3/private/s3_request_messages.h"
 #include "aws/s3/private/s3_util.h"
 #include "aws/s3/private/s3express_credentials_provider_impl.h"

From 25cec1642e044953beed0ca314166379b9719229 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:44:08 -0700
Subject: [PATCH 05/15] lint

---
 source/s3_request.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/s3_request.c b/source/s3_request.c
index b993b0769..fb982c6ac 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -47,8 +47,8 @@ struct aws_s3_request *aws_s3_request_new(
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
     /* +1 cause range end is inclusive */
-    uint64_t size = request->part_range_end - request->part_range_start + 1
-    return size > 0 ? size ? : request->meta_request->part_size;
+    uint64_t size = request->part_range_end - request->part_range_start + 1 return size > 0
+        ? size ?: request->meta_request->part_size;
 }
 
 static void s_populate_metrics_from_message(struct aws_s3_request *request, struct aws_http_message *message) {

From 90b752ef08ce18fb24fd4b4015f5bc7388a629be Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:48:48 -0700
Subject: [PATCH 06/15] expose function

---
 include/aws/s3/private/s3_request.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/aws/s3/private/s3_request.h b/include/aws/s3/private/s3_request.h
index c160ff11a..599805902 100644
--- a/include/aws/s3/private/s3_request.h
+++ b/include/aws/s3/private/s3_request.h
@@ -292,9 +292,9 @@ struct aws_s3_request *aws_s3_request_new(
     uint32_t part_number,
     uint32_t flags);
 
-/* Sets part boundary information on the request. */
+/* Gets the size of the part payload. returns metarequest part size if accurate size is not available. */
 AWS_S3_API
-void aws_s3_request_set_part_boundary(struct aws_s3_request *request, uint64_t part_start, uint64_t part_end);
+uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request);
 
 /* Set up the request to be sent. Called each time before the request is sent. Will initially call
  * aws_s3_request_clean_up_send_data to clear out anything previously existing in send_data. */

From dff74a6f939b86dfa1f997bc50d67cff9d68e897 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 14:53:27 -0700
Subject: [PATCH 07/15] fix formatting

---
 include/aws/s3/private/s3_request.h |  4 +++-
 source/s3_request.c                 | 15 +++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/aws/s3/private/s3_request.h b/include/aws/s3/private/s3_request.h
index 599805902..48f037f65 100644
--- a/include/aws/s3/private/s3_request.h
+++ b/include/aws/s3/private/s3_request.h
@@ -292,7 +292,9 @@ struct aws_s3_request *aws_s3_request_new(
     uint32_t part_number,
     uint32_t flags);
 
-/* Gets the size of the part payload. returns metarequest part size if accurate size is not available. */
+/* Gets the size of the part payload.
+ * returns metarequest part size if accurate size is not available for request that have part size body or response or 0
+ * otherwise. */
 AWS_S3_API
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request);
 
diff --git a/source/s3_request.c b/source/s3_request.c
index fb982c6ac..42a193dfd 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -47,8 +47,19 @@ struct aws_s3_request *aws_s3_request_new(
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
     /* +1 cause range end is inclusive */
-    uint64_t size = request->part_range_end - request->part_range_start + 1 return size > 0
-        ? size ?: request->meta_request->part_size;
+    uint64_t size = request->part_range_end - request->part_range_start + 1;
+
+    if (size > 0) {
+        return size;
+    }
+
+    if (request->request_type == AWS_S3_REQUEST_TYPE_GET_OBJECT ||
+        request->request_type == AWS_S3_REQUEST_TYPE_PUT_OBJECT ||
+        request->request_type == AWS_S3_REQUEST_TYPE_UPLOAD_PART) {
+        return request->meta_request->part_size;
+    }
+
+    return 0;
 }
 
 static void s_populate_metrics_from_message(struct aws_s3_request *request, struct aws_http_message *message) {

From 22de6ae5c32c94181f7c4c1cb281ecbd78004494 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 15:00:27 -0700
Subject: [PATCH 08/15] fix win cast

---
 source/s3_client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/s3_client.c b/source/s3_client.c
index c48979bfd..901e138ae 100644
--- a/source/s3_client.c
+++ b/source/s3_client.c
@@ -1910,7 +1910,7 @@ void s_acquire_mem_and_prepare_request(
         struct aws_s3_buffer_pool_reserve_meta meta = {
             .client = client,
             .meta_request = meta_request,
-            .size = aws_s3_request_get_part_size(request),
+            .size = (size_t)aws_s3_request_get_part_size(request),
         };
 
         struct aws_s3_reserve_memory_payload *payload =

From 34e5de2c45c91a31dc722a90831e0fb7199f6e21 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Mon, 8 Sep 2025 17:03:54 -0700
Subject: [PATCH 09/15] fix logic

---
 source/s3_request.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/source/s3_request.c b/source/s3_request.c
index 42a193dfd..d14975ba3 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -46,11 +46,15 @@ struct aws_s3_request *aws_s3_request_new(
 }
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
-    /* +1 cause range end is inclusive */
-    uint64_t size = request->part_range_end - request->part_range_start + 1;
-
-    if (size > 0) {
-        return size;
+    /* Note: this is still somewhat suboptimal as 0-0 is a valid 1 byte range, but 
+     * we will overallocate for it */
+    bool is_range_set = 
+        request->part_range_end != request->part_range_start || 
+        request->part_range_start != 0;
+
+    if (is_range_set) {
+        /* +1 cause range end is inclusive */
+        return request->part_range_end - request->part_range_start + 1;
     }
 
     if (request->request_type == AWS_S3_REQUEST_TYPE_GET_OBJECT ||

From 493869da1e8a76bb6587326093c16ce08e64bd60 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Tue, 9 Sep 2025 11:44:26 -0700
Subject: [PATCH 10/15] lint

---
 source/s3_request.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/source/s3_request.c b/source/s3_request.c
index d14975ba3..a7ce0db34 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -46,11 +46,9 @@ struct aws_s3_request *aws_s3_request_new(
 }
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
-    /* Note: this is still somewhat suboptimal as 0-0 is a valid 1 byte range, but 
+    /* Note: this is still somewhat suboptimal as 0-0 is a valid 1 byte range, but
      * we will overallocate for it */
-    bool is_range_set = 
-        request->part_range_end != request->part_range_start || 
-        request->part_range_start != 0;
+    bool is_range_set = request->part_range_end != request->part_range_start || request->part_range_start != 0;
 
     if (is_range_set) {
         /* +1 cause range end is inclusive */

From a1403ab8606fc700177b0419cc18220f0181970a Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Wed, 10 Sep 2025 11:39:03 -0700
Subject: [PATCH 11/15] address comments

---
 include/aws/s3/private/s3_request.h |  3 +--
 source/s3_auto_ranged_get.c         |  4 ++++
 source/s3_client.c                  |  7 +++++--
 source/s3_request.c                 | 19 ++++---------------
 4 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/include/aws/s3/private/s3_request.h b/include/aws/s3/private/s3_request.h
index 48f037f65..393ecc2b5 100644
--- a/include/aws/s3/private/s3_request.h
+++ b/include/aws/s3/private/s3_request.h
@@ -293,8 +293,7 @@ struct aws_s3_request *aws_s3_request_new(
     uint32_t flags);
 
 /* Gets the size of the part payload.
- * returns metarequest part size if accurate size is not available for request that have part size body or response or 0
- * otherwise. */
+ * Range is inclusive (i.e. 0-0 range has 1 byte size). In case of misconfigured range returns 0. */
 AWS_S3_API
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request);
 
diff --git a/source/s3_auto_ranged_get.c b/source/s3_auto_ranged_get.c
index 5a3249531..cd758eb03 100644
--- a/source/s3_auto_ranged_get.c
+++ b/source/s3_auto_ranged_get.c
@@ -253,6 +253,10 @@ static bool s_s3_auto_ranged_get_update(
                             1 /*part_number*/,
                             AWS_S3_REQUEST_FLAG_RECORD_RESPONSE_HEADERS |
                                 AWS_S3_REQUEST_FLAG_ALLOCATE_BUFFER_FROM_POOL);
+                        /* Note: our current default logic is to do part 1, discover size and then abort if payload its too huge
+                         * We optimistically reserve part size for it */
+                        request->part_range_start = 0; 
+                        request->part_range_end = meta_request->part_size;
                         ++auto_ranged_get->synced_data.num_parts_requested;
 
                         break;
diff --git a/source/s3_client.c b/source/s3_client.c
index 901e138ae..16cc09192 100644
--- a/source/s3_client.c
+++ b/source/s3_client.c
@@ -1897,7 +1897,10 @@ void s_acquire_mem_and_prepare_request(
     aws_s3_meta_request_prepare_request_callback_fn *callback,
     void *user_data) {
 
-    if (request->ticket == NULL && request->should_allocate_buffer_from_pool) {
+    size_t request_size = (size_t)aws_s3_request_get_part_size(request);
+    AWS_ASSERT(request_size != 0); /* Note: 0 request size is invalid in all cases. */
+
+    if (request->ticket == NULL && request->should_allocate_buffer_from_pool && request_size > 0) {
 
         if (request->send_data.metrics) {
             struct aws_s3_request_metrics *metric = request->send_data.metrics;
@@ -1910,7 +1913,7 @@ void s_acquire_mem_and_prepare_request(
         struct aws_s3_buffer_pool_reserve_meta meta = {
             .client = client,
             .meta_request = meta_request,
-            .size = (size_t)aws_s3_request_get_part_size(request),
+            .size = request_size,
         };
 
         struct aws_s3_reserve_memory_payload *payload =
diff --git a/source/s3_request.c b/source/s3_request.c
index a7ce0db34..83cf56209 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -46,22 +46,11 @@ struct aws_s3_request *aws_s3_request_new(
 }
 
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
-    /* Note: this is still somewhat suboptimal as 0-0 is a valid 1 byte range, but
-     * we will overallocate for it */
-    bool is_range_set = request->part_range_end != request->part_range_start || request->part_range_start != 0;
-
-    if (is_range_set) {
-        /* +1 cause range end is inclusive */
-        return request->part_range_end - request->part_range_start + 1;
-    }
-
-    if (request->request_type == AWS_S3_REQUEST_TYPE_GET_OBJECT ||
-        request->request_type == AWS_S3_REQUEST_TYPE_PUT_OBJECT ||
-        request->request_type == AWS_S3_REQUEST_TYPE_UPLOAD_PART) {
-        return request->meta_request->part_size;
+    uint64_t result = 0;
+    if (aws_sub_u64_checked(request->part_range_end, request->part_range_start, &result) != AWS_OP_SUCCESS) {
+        return 0; 
     }
-
-    return 0;
+    return result + 1;
 }
 
 static void s_populate_metrics_from_message(struct aws_s3_request *request, struct aws_http_message *message) {

From 23901ba272f21a234c075c017e000c0087b51c20 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Wed, 10 Sep 2025 11:40:49 -0700
Subject: [PATCH 12/15] lint

---
 source/s3_auto_ranged_get.c | 6 +++---
 source/s3_request.c         | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/source/s3_auto_ranged_get.c b/source/s3_auto_ranged_get.c
index cd758eb03..96987c8d0 100644
--- a/source/s3_auto_ranged_get.c
+++ b/source/s3_auto_ranged_get.c
@@ -253,9 +253,9 @@ static bool s_s3_auto_ranged_get_update(
                             1 /*part_number*/,
                             AWS_S3_REQUEST_FLAG_RECORD_RESPONSE_HEADERS |
                                 AWS_S3_REQUEST_FLAG_ALLOCATE_BUFFER_FROM_POOL);
-                        /* Note: our current default logic is to do part 1, discover size and then abort if payload its too huge
-                         * We optimistically reserve part size for it */
-                        request->part_range_start = 0; 
+                        /* Note: our current default logic is to do part 1, discover size and then abort if payload its
+                         * too huge We optimistically reserve part size for it */
+                        request->part_range_start = 0;
                         request->part_range_end = meta_request->part_size;
                         ++auto_ranged_get->synced_data.num_parts_requested;
 
diff --git a/source/s3_request.c b/source/s3_request.c
index 83cf56209..179a6b56b 100644
--- a/source/s3_request.c
+++ b/source/s3_request.c
@@ -48,7 +48,7 @@ struct aws_s3_request *aws_s3_request_new(
 uint64_t aws_s3_request_get_part_size(struct aws_s3_request *request) {
     uint64_t result = 0;
     if (aws_sub_u64_checked(request->part_range_end, request->part_range_start, &result) != AWS_OP_SUCCESS) {
-        return 0; 
+        return 0;
     }
     return result + 1;
 }

From 92d743c94720570a44ab26c464f7003c100f9c07 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Wed, 10 Sep 2025 13:26:48 -0700
Subject: [PATCH 13/15] add logging

---
 source/s3_auto_ranged_get.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/source/s3_auto_ranged_get.c b/source/s3_auto_ranged_get.c
index 96987c8d0..ebddc6489 100644
--- a/source/s3_auto_ranged_get.c
+++ b/source/s3_auto_ranged_get.c
@@ -256,7 +256,7 @@ static bool s_s3_auto_ranged_get_update(
                         /* Note: our current default logic is to do part 1, discover size and then abort if payload its
                          * too huge We optimistically reserve part size for it */
                         request->part_range_start = 0;
-                        request->part_range_end = meta_request->part_size;
+                        request->part_range_end = meta_request->part_size - 1;
                         ++auto_ranged_get->synced_data.num_parts_requested;
 
                         break;
@@ -288,8 +288,9 @@ static bool s_s3_auto_ranged_get_update(
                         }
                         AWS_LOGF_INFO(
                             AWS_LS_S3_META_REQUEST,
-                            "id=%p: Doing a ranged get to discover the size of the object and get the first part",
-                            (void *)meta_request);
+                            "id=%p: Doing a ranged get to discover the size of the object and get the first part %zu %zu",
+                            (void *)meta_request, part_range_start, first_part_size
+                        );
 
                         request = aws_s3_request_new(
                             meta_request,

From e54e88bfcfef17c200d09562336f0d869f52cb9a Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Sun, 14 Sep 2025 17:57:13 -0700
Subject: [PATCH 14/15] fix error case

---
 source/s3_meta_request.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/s3_meta_request.c b/source/s3_meta_request.c
index 50d856661..f1a86a39b 100644
--- a/source/s3_meta_request.c
+++ b/source/s3_meta_request.c
@@ -1429,7 +1429,7 @@ static int s_s3_meta_request_incoming_body(
 
     if (request->send_data.response_body.capacity == 0) {
         /* Make sure that request is get, since puts can also have ticket allocated, which is used for request body. */
-        if (request->request_type == AWS_S3_REQUEST_TYPE_GET_OBJECT && request->ticket != NULL) {
+        if (successful_response && request->request_type == AWS_S3_REQUEST_TYPE_GET_OBJECT && request->ticket != NULL) {
             request->send_data.response_body = aws_s3_buffer_ticket_claim(request->ticket);
         } else {
             size_t buffer_size = s_dynamic_body_initial_buf_size;

From c0b262a4bfaca5a470526ef36595886a06fcd4b0 Mon Sep 17 00:00:00 2001
From: DmitriyMusatkin <musatkd@amazon.com>
Date: Sun, 14 Sep 2025 18:13:33 -0700
Subject: [PATCH 15/15] build error

---
 source/s3_auto_ranged_get.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/source/s3_auto_ranged_get.c b/source/s3_auto_ranged_get.c
index ebddc6489..7b4f3178f 100644
--- a/source/s3_auto_ranged_get.c
+++ b/source/s3_auto_ranged_get.c
@@ -288,8 +288,8 @@ static bool s_s3_auto_ranged_get_update(
                         }
                         AWS_LOGF_INFO(
                             AWS_LS_S3_META_REQUEST,
-                            "id=%p: Doing a ranged get to discover the size of the object and get the first part %zu %zu",
-                            (void *)meta_request, part_range_start, first_part_size
+                            "id=%p: Doing a ranged get to discover the size of the object and get the first part",
+                            (void *)meta_request
                         );
 
                         request = aws_s3_request_new(