From 54daf70308495bc4ec0151d38ca80f941b13875a Mon Sep 17 00:00:00 2001
From: ferdymercury <ferdymercury@users.noreply.github.com>
Date: Sun, 6 Oct 2024 20:16:27 +0200
Subject: [PATCH] [tree] Fix invalid macro names when absolute filepath is
 passed

Fixes https://github.com/root-project/root/issues/16562
---
 tree/treeviewer/CMakeLists.txt      | 4 ++++
 tree/treeviewer/src/TTreeViewer.cxx | 6 +++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/tree/treeviewer/CMakeLists.txt b/tree/treeviewer/CMakeLists.txt
index 46cd87d9f1aaf..af9a46df3c936 100644
--- a/tree/treeviewer/CMakeLists.txt
+++ b/tree/treeviewer/CMakeLists.txt
@@ -41,3 +41,7 @@ ROOT_STANDARD_LIBRARY_PACKAGE(TreeViewer
     Gui
     TreePlayer
 )
+if (CMAKE_COMPILER_IS_GNUCC AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9.0)
+    target_link_libraries(TreeViewer PUBLIC stdc++fs) # https://github.com/avast/retdec/issues/842
+endif()
+
diff --git a/tree/treeviewer/src/TTreeViewer.cxx b/tree/treeviewer/src/TTreeViewer.cxx
index eb9ad0616048e..48b6aeafdbce2 100644
--- a/tree/treeviewer/src/TTreeViewer.cxx
+++ b/tree/treeviewer/src/TTreeViewer.cxx
@@ -226,6 +226,8 @@ or :
 #include "strlcpy.h"
 #include "snprintf.h"
 
+#include <filesystem>
+
 #ifdef WIN32
 #include "TWin32SplashThread.h"
 #endif
@@ -2741,10 +2743,8 @@ void TTreeViewer::SaveSource(const char* filename, Option_t *)
    }
    //   Write macro header and date/time stamp
    TDatime t;
-   TString sname(fname);
-   sname = sname.ReplaceAll(".C", "");
    out <<"void open_session(void *p = 0);"<<std::endl<<std::endl;
-   out <<"void "<<sname.Data()<<"() {"<<std::endl;
+   out <<"void "<<std::filesystem::path(fname).stem()<<"() {"<<std::endl;
    out <<"//=========Macro generated by ROOT version"<<gROOT->GetVersion()<<std::endl;
    out <<"//=========for tree "<<quote<<fTree->GetName()<<quote<<" ("<<t.AsString()<<")"<<std::endl;
    out <<"//===This macro can be opened from a TreeViewer session after loading"<<std::endl;