[Lldb-commits] [lldb] [lldb-dap] Avoid double 'new' events for dyld on Darwin (PR #140810)

[Jonas Devlieghere via lldb-commits]

https://github.com/JDevlieghere created https://github.com/llvm/llvm-project/pull/140810

I got a bug report where a pedantic DAP client complains about getting two "new" module events for the same UUID. This is caused by the dyld transition from the on-disk dyld to the shared cache dyld, which share the same UUID. The transition is not generating an unloaded event (because we're not really unloading dyld) but we do get a loaded event (because the load address changed). This PR fixes the issue by relying on the modules set as the source of truth instead of relying on the event type.

>From e9314a68b7e95aef26a1e75460f2e10b0c4b8ec3 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Tue, 20 May 2025 14:05:31 -0700
Subject: [PATCH] [lldb-dap] Avoid double 'new' events for dyld on Darwin

I got a bug report where a pedantic DAP client complains about getting
two "new" module events for the same UUID. This is caused by the dyld
transition from the on-disk dyld to the shared cache dyld, which share
the same UUID. The transition is not generating an unloaded
event (because we're not really unloading dyld) but we do
get a loaded event (because the load address changed). This PR fixes the
issue by relying on the modules set as the source of truth instead of
relying on the event type.
---
 lldb/tools/lldb-dap/DAP.cpp | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp
index 3419b2c3a841b..f6241b7d98456 100644
--- a/lldb/tools/lldb-dap/DAP.cpp
+++ b/lldb/tools/lldb-dap/DAP.cpp
@@ -1292,15 +1292,7 @@ void DAP::EventThread() {
 
             llvm::StringRef reason;
             bool id_only = false;
-            if (event_mask & lldb::SBTarget::eBroadcastBitModulesLoaded) {
-              modules.insert(module_id);
-              reason = "new";
-            } else {
-              // If this is a module we've never told the client about, don't
-              // send an event.
-              if (!modules.contains(module_id))
-                continue;
-
+            if (modules.contains(module_id)) {
               if (event_mask & lldb::SBTarget::eBroadcastBitModulesUnloaded) {
                 modules.erase(module_id);
                 reason = "removed";
@@ -1308,6 +1300,9 @@ void DAP::EventThread() {
               } else {
                 reason = "changed";
               }
+            } else {
+              modules.insert(module_id);
+              reason = "new";
             }
 
             llvm::json::Object body;