Issue with incremental builds

[TomasDado]

Check duplicate issues.

• Checked for duplicates

Description

Hello,

I compiled ROOT master branch from yesterday (build from source) with:

cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DPython3_ROOT_DIR=/usr/bin/python3 -Dxrootd=OFF -Dmathmore=ON -Ddavix=OFF -Dbuiltin_tbb=ON  -DCMAKE_INSTALL_PREFIX=../install/ ../root_src/

I rebased the source code to today's version and then just ran:

cmake --build . --target install -j10

However, the build fails with:

[ 63%] Generating G__MultiProc.cxx, ../../lib/MultiProc.pcm
In file included from input_line_7:10:
/home/tomas/ROOT/build/include/MPSendRecv.h:18:10: remark: building module 'Net' as '/home/tomas/ROOT/build/lib/Net.pcm' [-Rmodule-build]
#include "TSocket.h"
         ^
Error: Building module 'Net' implicitly. If 'Net' requires a 
dictionary please specify build dependency: 'G__MultiProc.cxx' depends on 'Net'.
Otherwise, specify '-mByproduct Net' to disable this diagnostic.
[ 63%] Generating G__SQLIO.cxx, ../../lib/SQLIO.pcm
[ 63%] Generating G__RootAuth.cxx, ../../lib/RootAuth.pcm
[ 63%] Building CXX object net/rpdutils/CMakeFiles/SrvAuth.dir/src/DaemonUtils.cxx.o
[ 63%] Building CXX object net/rpdutils/CMakeFiles/SrvAuth.dir/src/rpdutils.cxx.o
gmake[2]: *** [core/multiproc/CMakeFiles/G__MultiProc.dir/build.make:94: core/multiproc/G__MultiProc.cxx] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:52802: core/multiproc/CMakeFiles/G__MultiProc.dir/all] Error 2
gmake[1]: *** Waiting for unfinished jobs....
[ 63%] Built target G__MathCore

This seems like some dependancies are not properly rebuilt with an incremental update?

This is my gcc version:

gcc (Ubuntu 15.2.0-4ubuntu4) 15.2.0

Reproducer

Repeat the build setup above with changes in the source code that affect ROOT dictionaries

ROOT version

commit: 5e6a359

Installation method

Build from source

Operating system

Ubuntu 25.10

Additional context

No response

[dpiparo]

Hi @TomasDado , thanks for the report. We did not see this coming in our incremental builds...

[TomasDado]

Yes, I am also surprised but I have seen it many times before only reported it now, I am happy to provide more info if needed

[dpiparo]

thanks. Could you please also share the list of components installed: I am curious to see what's the situation with the builtins.

[TomasDado]

I am am really not an expert on cmake so I am not sure what you need exactly, sorry. I am attaching the install_manifest.txt files. Please, let me know if you need something else.

As note, to fix the compilation, I not only had to remove the contents of the build folder, but also the install folder.

install_manifest.txt

[ferdymercury]

I am not sure what you need exactly, sorry

I think he meant that, when you call "cmake" (before building), ROOT prints something like:

Built with support for python3 rdataframe modules asimage roofit xxxxx xxxx

so copy-pasting that line.

[TomasDado]

Ah thanks! This is what the cmake steps give:

-- Enabled support for:  asimage builtin_clang builtin_cling builtin_civetweb builtin_jpeg builtin_llvm builtin_openui5 builtin_tbb check_connection clad curl dataframe fitsio gdml geom http imt mathmore opengl pyroot roofit root7 runtime_cxxmodules shared spectrum ssl thisroot_scripts tmva tmva-cpu tmva-cudnn tpython use_gsl_cblas vdt webgui x11 xml

[guitargeek]

Problem identified and PR with a fix opened:

• [CMake] Make dictionary module dependencies independent of config order #22648