Merge pull request #6959 from apple/dl/lldb-Prevent-dwim-print-from-showing-kNoResult-error

[lldb] Prevent dwim-print from showing kNoResult error

Author: adrian-prantl

lldb/source/Commands/CommandObjectDWIMPrint.cpp

@@ -11,6 +11,7 @@
 #include "lldb/Core/ValueObject.h"
 #include "lldb/DataFormatters/DumpValueObjectOptions.h"
 #include "lldb/Expression/ExpressionVariable.h"
+#include "lldb/Expression/UserExpression.h"
 #include "lldb/Interpreter/CommandInterpreter.h"
 #include "lldb/Interpreter/CommandObject.h"
 #include "lldb/Interpreter/CommandReturnObject.h"
@@ -178,7 +179,8 @@ bool CommandObjectDWIMPrint::DoExecute(StringRef command,
                                         expr);
       }
 
-      valobj_sp->Dump(result.GetOutputStream(), dump_options);
+      if (valobj_sp->GetError().GetError() != UserExpression::kNoResult)
+        valobj_sp->Dump(result.GetOutputStream(), dump_options);
 
       if (suppress_result)
         if (auto result_var_sp =

lldb/test/API/commands/dwim-print/TestDWIMPrint.py

@@ -138,3 +138,9 @@ def test_summary_strings(self):
         self.runCmd("type summary add -e -s 'stub summary' Structure")
         self._expect_cmd(f"dwim-print s", "frame variable")
         self._expect_cmd(f"dwim-print (struct Structure)s", "expression")
+
+    def test_void_result(self):
+        """Test dwim-print does not surface an error message for void expressions."""
+        self.build()
+        lldbutil.run_to_source_breakpoint(self, "// break here", lldb.SBFileSpec("main.c"))
+        self.expect("dwim-print (void)15", matching=False, patterns=["(?i)error"])