From b1430f845f95b5c62998733c68ff8437af8f96c8 Mon Sep 17 00:00:00 2001
From: vyniciuspontes <vynicius.moraispontes@freestar.io>
Date: Mon, 18 Dec 2023 19:44:18 -0300
Subject: [PATCH 1/2] fix: prevent ExchangeService to empty Source object when
 TRANSMIT_TID is false and supplyChainResolver can't resolve a schain for
 bidder

---
 .../org/prebid/server/auction/ExchangeService.java    | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/prebid/server/auction/ExchangeService.java b/src/main/java/org/prebid/server/auction/ExchangeService.java
index 8f5e108cb8d..0d3c57427c8 100644
--- a/src/main/java/org/prebid/server/auction/ExchangeService.java
+++ b/src/main/java/org/prebid/server/auction/ExchangeService.java
@@ -1137,8 +1137,15 @@ private Source prepareSource(String bidder, BidRequest bidRequest, boolean trans
         final Source receivedSource = bidRequest.getSource();
         final SupplyChain bidderSchain = supplyChainResolver.resolveForBidder(bidder, bidRequest);
 
-        if (bidderSchain == null && transmitTid) {
-            return receivedSource;
+        if (bidderSchain == null) {
+
+            if (receivedSource == null) {
+                return null;
+            }
+
+            return receivedSource.toBuilder()
+                    .tid(transmitTid ? receivedSource.getTid() : null)
+                    .build();
         }
 
         return receivedSource == null

From 83bf3af7d663ca452158df8e9d907dfbcd4a2b43 Mon Sep 17 00:00:00 2001
From: vyniciuspontes <vynicius.moraispontes@freestar.io>
Date: Tue, 19 Dec 2023 11:25:32 -0300
Subject: [PATCH 2/2] fix: improve logic and add tests

---
 .../server/auction/ExchangeService.java       | 17 +++----
 .../server/auction/ExchangeServiceTest.java   | 44 +++++++++++++++++++
 2 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/src/main/java/org/prebid/server/auction/ExchangeService.java b/src/main/java/org/prebid/server/auction/ExchangeService.java
index 0d3c57427c8..51c488f93fd 100644
--- a/src/main/java/org/prebid/server/auction/ExchangeService.java
+++ b/src/main/java/org/prebid/server/auction/ExchangeService.java
@@ -1135,25 +1135,18 @@ private static Content prepareContent(Content content) {
      */
     private Source prepareSource(String bidder, BidRequest bidRequest, boolean transmitTid) {
         final Source receivedSource = bidRequest.getSource();
-        final SupplyChain bidderSchain = supplyChainResolver.resolveForBidder(bidder, bidRequest);
-
-        if (bidderSchain == null) {
 
-            if (receivedSource == null) {
-                return null;
-            }
+        final SupplyChain bidderSchain = supplyChainResolver.resolveForBidder(bidder, bidRequest);
 
-            return receivedSource.toBuilder()
-                    .tid(transmitTid ? receivedSource.getTid() : null)
-                    .build();
+        if (bidderSchain == null && transmitTid) {
+            return receivedSource;
         }
 
         return receivedSource == null
                 ? Source.builder().schain(bidderSchain).build()
                 : receivedSource.toBuilder()
-                .schain(bidderSchain)
-                .tid(transmitTid ? receivedSource.getTid() : null)
-                .build();
+                .schain(bidderSchain != null ? bidderSchain : receivedSource.getSchain())
+                .tid(transmitTid ? receivedSource.getTid() : null).build();
     }
 
     /**
diff --git a/src/test/java/org/prebid/server/auction/ExchangeServiceTest.java b/src/test/java/org/prebid/server/auction/ExchangeServiceTest.java
index 50f1b56285d..ead94430e61 100644
--- a/src/test/java/org/prebid/server/auction/ExchangeServiceTest.java
+++ b/src/test/java/org/prebid/server/auction/ExchangeServiceTest.java
@@ -1039,6 +1039,50 @@ public void shouldPassTidsIfCreateTidsTrue() {
                 .containsExactly(TextNode.valueOf("bidderTidValue"));
     }
 
+    @Test
+    public void shouldRemoveTidsIfCreateTidsFalseAndKeepReceivedSchain() {
+        // given
+        final String bidderName = "bidder";
+        final Bidder<?> bidder = mock(Bidder.class);
+        givenBidder(bidderName, bidder, givenEmptySeatBid());
+
+        final Imp imp = givenImp(Map.of(bidderName, 1), identity());
+        imp.getExt().put("tid", "bidderTidValue");
+        final BidRequest bidRequest = givenBidRequest(
+                singletonList(imp),
+                builder -> builder
+                        .source(Source.builder().tid("sourceTidValue").schain(SupplyChain.of(1,
+                                List.of(SupplyChainNode.of("freestar.com", "66", null, null,
+                                        null, 1, null)), "1.0", null))
+                                .build())
+                        .ext(ExtRequest.of(
+                                ExtRequestPrebid.builder()
+                                        .createTids(false)
+                                        .build())));
+
+        // when
+        target.holdAuction(givenRequestContext(bidRequest));
+
+        // then
+        final ArgumentCaptor<BidderRequest> bidRequestCaptor = ArgumentCaptor.forClass(BidderRequest.class);
+        verify(httpBidderRequester)
+                .requestBids(same(bidder), bidRequestCaptor.capture(), any(), any(), any(), any(), anyBoolean());
+
+        final BidRequest capturedBidRequest = bidRequestCaptor.getValue().getBidRequest();
+        assertThat(capturedBidRequest)
+                .extracting(BidRequest::getSource)
+                .extracting(Source::getTid)
+                .isNull();
+        assertThat(capturedBidRequest)
+                .extracting(BidRequest::getSource)
+                .extracting(Source::getSchain)
+                .isNotNull();
+        assertThat(capturedBidRequest.getImp())
+                .extracting(Imp::getExt)
+                .extracting(ext -> ext.get("tid"))
+                .containsOnlyNulls();
+    }
+
     @Test
     public void shouldRemoveTidsIfTransmitTidActivityDisallowed() {
         // given