From 2df2dba9e828261e8278bca02817e212128d76aa Mon Sep 17 00:00:00 2001
From: Roy Stogner <Roy.Stogner@inl.gov>
Date: Thu, 28 May 2026 15:28:18 -0500
Subject: [PATCH 1/3] Leave GDB_COMMAND undefined if it's undefined

This way we can use the preprocessor to check when it's undefined, not
just the compiler.
---
 m4/libmesh_core_features.m4 | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/m4/libmesh_core_features.m4 b/m4/libmesh_core_features.m4
index bf3f02d20f0..9dea78752dc 100644
--- a/m4/libmesh_core_features.m4
+++ b/m4/libmesh_core_features.m4
@@ -19,8 +19,14 @@ AC_ARG_WITH([gdb-command],
     [gdb_command="$withval"],
     [gdb_command="no"])
 
-AC_DEFINE_UNQUOTED(GDB_COMMAND, "$gdb_command", [command to invoke gdb])
-AC_MSG_RESULT([configuring gdb command... "$gdb_command"])
+AS_IF([test "$gdb_command" != no],
+      [
+        AC_DEFINE_UNQUOTED(GDB_COMMAND, "$gdb_command", [command to invoke gdb])
+        AC_MSG_RESULT([configuring gdb command... "$gdb_command"])
+      ],
+      [
+        AC_MSG_RESULT([configuring with no gdb"])
+      ])
 # -------------------------------------------------------------
 
 

From 280883f57f4a2dd8fe6f1b894cd7596e41dbc424 Mon Sep 17 00:00:00 2001
From: Roy Stogner <Roy.Stogner@inl.gov>
Date: Thu, 28 May 2026 15:47:44 -0500
Subject: [PATCH 2/3] Better GDB_COMMAND handling

Don't futz with comparing GDB_COMMAND to "no" at run-time (this fixes
an "unreachable code" warning for me with GDB_COMMAND=no with my clang++
and newer C++ standards)

Do allow for run-time `--gdb=` even if it was disabled at compile-time.
---
 src/base/print_trace.C | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/base/print_trace.C b/src/base/print_trace.C
index 7e8b7e0fef6..8a88043eb46 100644
--- a/src/base/print_trace.C
+++ b/src/base/print_trace.C
@@ -133,7 +133,6 @@ std::string process_trace(const char * name)
 // source code, a really helpful feature when debugging something...
 bool gdb_backtrace(std::ostream & out_stream)
 {
-#ifdef LIBMESH_GDB_COMMAND
   // Eventual return value, true if gdb succeeds, false otherwise.
   bool success = true;
 
@@ -156,8 +155,15 @@ bool gdb_backtrace(std::ostream & out_stream)
 
       libmesh_try
         {
+#ifdef LIBMESH_GDB_COMMAND
           std::string gdb_command =
             libMesh::command_line_value("gdb",std::string(LIBMESH_GDB_COMMAND));
+#else
+          if (!libMesh::on_command_line("--gdb"))
+            return false;
+          std::string gdb_command =
+            libMesh::command_line_value("gdb",std::string());
+#endif
 
           std::ostringstream command;
           command << gdb_command
@@ -188,9 +194,6 @@ bool gdb_backtrace(std::ostream & out_stream)
   std::remove(temp_file);
 
   return success;
-#else
-  return false;
-#endif
 }
 
 } // end anonymous namespace
@@ -210,8 +213,10 @@ void print_trace(std::ostream & out_stream)
 
   // Let the user disable GDB backtraces by configuring with
   // --without-gdb-command or with a command line option.
-  if ((std::string(LIBMESH_GDB_COMMAND) != std::string("no") &&
-       !libMesh::on_command_line("--no-gdb-backtrace")) ||
+  if (
+#ifdef LIBMESH_GDB_COMMAND
+      !libMesh::on_command_line("--no-gdb-backtrace") ||
+#endif
       libMesh::on_command_line("--gdb"))
     gdb_worked = gdb_backtrace(out_stream);
 

From 0082cdb52c6b19ab9e85221cd38439929cc21edc Mon Sep 17 00:00:00 2001
From: Roy Stogner <Roy.Stogner@inl.gov>
Date: Thu, 28 May 2026 15:59:03 -0500
Subject: [PATCH 3/3] Re-bootstrap

---
 configure | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index 68b5c9981eb..3d7470fc1d5 100755
--- a/configure
+++ b/configure
@@ -61111,11 +61111,22 @@ esac
 fi
 
 
+if test "$gdb_command" != no
+then :
+
 
 printf "%s\n" "#define GDB_COMMAND \"$gdb_command\"" >>confdefs.h
 
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: configuring gdb command... \"$gdb_command\"" >&5
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: configuring gdb command... \"$gdb_command\"" >&5
 printf "%s\n" "configuring gdb command... \"$gdb_command\"" >&6; }
+
+else case e in #(
+  e)
+        { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: configuring with no gdb\"" >&5
+printf "%s\n" "configuring with no gdb\"" >&6; }
+       ;;
+esac
+fi
 # -------------------------------------------------------------