Merge pull request #3865 from apple/lldb-Unlock-Swift-scratch-context-before-early-return

[lldb] Unlock Swift scratch context before early return

Author: kastiglione

lldb/source/Target/Target.cpp

@@ -2286,6 +2286,9 @@ Target::GetScratchTypeSystemForLanguage(lldb::LanguageType language,
         // thread) is holding a read lock to the scratch context and
         // replacing it could cause a use-after-free later on.
         if (GetSwiftScratchContextLock().try_lock()) {
+          auto unlock = llvm::make_scope_exit([this] {
+            GetSwiftScratchContextLock().unlock();
+          });
           if (m_use_scratch_typesystem_per_module)
             DisplayFallbackSwiftContextErrors(swift_ast_ctx);
           else if (StreamSP errs = GetDebugger().GetAsyncErrorStream()) {
@@ -2335,7 +2338,6 @@ Target::GetScratchTypeSystemForLanguage(lldb::LanguageType language,
                   llvm::make_error<llvm::StringError>("DIAF", llvm::inconvertibleErrorCode());
             }
           }
-          GetSwiftScratchContextLock().unlock();
         }
       }
     } else if (create_on_demand) {