Build error with "nlohmann/json.hpp: No such file or directory" in spack (unit tests build, with --test=root option) about root

[ferdymercury]

Please try with master branch, or with 6.30.04, this seems a duplicate of:
#14188
which was recently fixed.

[vvolkl]

Or add https://github.com/root-project/root/pull/14192/files.patch as a patch.

[github-actions]

Hi @ferdymercury,

It appears this issue is closed, but wasn't yet added to a project. Please add upcoming versions that will include the fix, or 'not applicable' otherwise.

Sincerely,
🤖

[wkensuke]

@ferdymercury @vvolkl

Thank you for your responses!
I followed the advice and built with version 6.30.04 and the master branch.

Unfortunately, the results were the same. Attached are the build logs.
spack-build-out_root-6.30.04.txt
spack-build-out_root-master.txt

Check the cmake configuration and modify tree/dataframe/test/CMakeLists.txt as follows:

--- a/tree/dataframe/test/CMakeLists.txt
+++ b/tree/dataframe/test/CMakeLists.txt
@@ -45,6 +45,7 @@
 endif()

 ROOT_ADD_GTEST(dataframe_datasetspec dataframe_datasetspec.cxx LIBRARIES ROOTDataFrame)
+target_include_directories(dataframe_datasetspec BEFORE PRIVATE ${CMAKE_SOURCE_DIR}/builtins/)
 ROOT_ADD_GTEST(dataframe_display dataframe_display.cxx LIBRARIES ROOTDataFrame)
 ROOT_ADD_GTEST(dataframe_ranges dataframe_ranges.cxx LIBRARIES ROOTDataFrame)
 ROOT_ADD_GTEST(dataframe_leaves dataframe_leaves.cxx LIBRARIES ROOTDataFrame)

BEFORE and PRIVATE refer to other descriptions but do not understand their meaning.

[ferdymercury]

@linev might know.
Maybe it's not until 6.30.06 that it was fixed. Please compare the CMakeLists of master vs yours and try editing it by hand.

[linev]

As I can see from the full log, '-Dbuiltin_nlohmannjson:BOOL=OFF' is set there.
Means external nlohmann/json.hpp will be used when building ROOT.

In such case all tests also have to use external includes. I will try to provide fix.

[linev]

Please try #14784

[wkensuke]

@linev @vvolkl

Thank you.

Please try #14784
I built with this patch and was able to complete successfully.