Test failures when compiling ROOT with gcc 15

[ellert]

Check duplicate issues.

• Checked for duplicates

Description

When compiling root with gcc 15 many roofit tests fail.
Also one pythin test fails.

The following tests FAILED:
	 63 - pyunittests-bindings-pyroot-pythonizations-pyroot-pyz-tf-pycallables (Failed)
	1026 - tutorial-roofit-rf802_mcstudy_addons (Failed)     tutorial
	1248 - tutorial-fit-NumericalMinimization-py (Failed)    tutorial
	1249 - tutorial-fit-combinedFit-py (Failed)              python_runtime_deps tutorial
	1250 - tutorial-fit-fitConvolution-py (Failed)           tutorial
	1251 - tutorial-fit-fitNormSum-py (Failed)               tutorial
	1268 - tutorial-math-exampleFunction-py (Failed)         tutorial
	1297 - tutorial-roofit-rf101_basics-py (Failed)          tutorial
	1298 - tutorial-roofit-rf102_dataimport-py (Failed)      tutorial
	1299 - tutorial-roofit-rf103_interprfuncs-py (Failed)    tutorial
	1300 - tutorial-roofit-rf104_classfactory-py (Failed)    tutorial
	1301 - tutorial-roofit-rf105_funcbinding-py (Failed)     tutorial
	1302 - tutorial-roofit-rf106_plotdecoration-py (Failed)  tutorial
	1303 - tutorial-roofit-rf107_plotstyles-py (Failed)      tutorial
	1304 - tutorial-roofit-rf108_plotbinning-py (Failed)     tutorial
	1305 - tutorial-roofit-rf109_chi2residpull-py (Failed)   tutorial
	1306 - tutorial-roofit-rf110_normintegration-py (Failed) tutorial
	1308 - tutorial-roofit-rf201_composite-py (Failed)       tutorial
	1309 - tutorial-roofit-rf202_extendedmlfit-py (Failed)   tutorial
	1310 - tutorial-roofit-rf203_ranges-py (Failed)          tutorial
	1313 - tutorial-roofit-rf205_compplot-py (Failed)        tutorial
	1315 - tutorial-roofit-rf207_comptools-py (Failed)       tutorial
	1316 - tutorial-roofit-rf208_convolution-py (Failed)     tutorial
	1318 - tutorial-roofit-rf210_angularconv-py (Failed)     tutorial
	1319 - tutorial-roofit-rf211_paramconv-py (Failed)       tutorial
	1321 - tutorial-roofit-rf301_composition-py (Failed)     tutorial
	1323 - tutorial-roofit-rf303_conditional-py (Failed)     tutorial
	1324 - tutorial-roofit-rf304_uncorrprod-py (Failed)      tutorial
	1325 - tutorial-roofit-rf305_condcorrprod-py (Failed)    tutorial
	1326 - tutorial-roofit-rf306_condpereventerrors-py (Failed) tutorial
	1327 - tutorial-roofit-rf307_fullpereventerrors-py (Failed) tutorial
	1328 - tutorial-roofit-rf308_normintegration2d-py (Failed) tutorial
	1329 - tutorial-roofit-rf309_ndimplot-py (Failed)        tutorial
	1330 - tutorial-roofit-rf310_sliceplot-py (Failed)       tutorial
	1331 - tutorial-roofit-rf311_rangeplot-py (Failed)       tutorial
	1332 - tutorial-roofit-rf312_multirangefit-py (Failed)   tutorial
	1333 - tutorial-roofit-rf313_paramranges-py (Failed)     tutorial
	1334 - tutorial-roofit-rf314_paramfitrange-py (Failed)   tutorial
	1335 - tutorial-roofit-rf315_projectpdf-py (Failed)      tutorial
	1336 - tutorial-roofit-rf316_llratioplot-py (Failed)     tutorial
	1337 - tutorial-roofit-rf401_importttreethx-py (Failed)  tutorial
	1338 - tutorial-roofit-rf402_datahandling-py (Failed)    tutorial
	1339 - tutorial-roofit-rf403_weightedevts-py (Failed)    tutorial
	1340 - tutorial-roofit-rf404_categories-py (Failed)      tutorial
	1341 - tutorial-roofit-rf405_realtocatfuncs-py (Failed)  tutorial
	1342 - tutorial-roofit-rf406_cattocatfuncs-py (Failed)   tutorial
	1343 - tutorial-roofit-rf407_latextables-py (Failed)     tutorial
	1346 - tutorial-roofit-rf501_simultaneouspdf-py (Failed) tutorial
	1347 - tutorial-roofit-rf502_wspacewrite-py (Failed)     tutorial
	1349 - tutorial-roofit-rf504_simwstool-py (Failed)       tutorial
	1350 - tutorial-roofit-rf505_asciicfg-py (Failed)        tutorial
	1351 - tutorial-roofit-rf506_msgservice-py (Failed)      tutorial
	1353 - tutorial-roofit-rf509_wsinteractive-py (Failed)   tutorial
	1354 - tutorial-roofit-rf510_wsnamedsets-py (Failed)     tutorial
	1355 - tutorial-roofit-rf511_wsfactory_basic-py (Failed) tutorial
	1360 - tutorial-roofit-rf601_intminuit-py (Failed)       tutorial
	1361 - tutorial-roofit-rf602_chi2fit-py (Failed)         tutorial
	1362 - tutorial-roofit-rf603_multicpu-py (Failed)        tutorial
	1363 - tutorial-roofit-rf604_constraints-py (Failed)     tutorial
	1364 - tutorial-roofit-rf605_profilell-py (Failed)       tutorial
	1365 - tutorial-roofit-rf606_nllerrorhandling-py (Failed) tutorial
	1366 - tutorial-roofit-rf607_fitresult-py (Failed)       tutorial
	1367 - tutorial-roofit-rf608_fitresultaspdf-py (Failed)  tutorial
	1368 - tutorial-roofit-rf609_xychi2fit-py (Failed)       tutorial
	1369 - tutorial-roofit-rf610_visualerror-py (Failed)     tutorial
	1371 - tutorial-roofit-rf613_global_observables-py (Failed) tutorial
	1372 - tutorial-roofit-rf614_binned_fit_problems-py (Failed) tutorial
	1374 - tutorial-roofit-rf701_efficiencyfit-py (Failed)   tutorial
	1375 - tutorial-roofit-rf702_efficiencyfit_2D-py (Failed) tutorial
	1376 - tutorial-roofit-rf703_effpdfprod-py (Failed)      tutorial
	1377 - tutorial-roofit-rf704_amplitudefit-py (Failed)    tutorial
	1378 - tutorial-roofit-rf705_linearmorph-py (Failed)     tutorial
	1379 - tutorial-roofit-rf706_histpdf-py (Failed)         tutorial
	1380 - tutorial-roofit-rf707_kernelestimation-py (Failed) tutorial
	1381 - tutorial-roofit-rf708_bphysics-py (Failed)        tutorial
	1382 - tutorial-roofit-rf709_BarlowBeeston-py (Failed)   tutorial
	1384 - tutorial-roofit-rf711_lagrangianmorph-py (Failed) tutorial
	1386 - tutorial-roofit-rf801_mcstudy-py (Failed)         tutorial
	1387 - tutorial-roofit-rf802_mcstudy_addons-py (Failed)  tutorial
	1388 - tutorial-roofit-rf803_mcstudy_addons2-py (Failed) tutorial
	1389 - tutorial-roofit-rf804_mcstudy_constr-py (Failed)  tutorial
	1390 - tutorial-roofit-rf901_numintconfig-py (Failed)    tutorial
	1391 - tutorial-roofit-rf902_numgenconfig-py (Failed)    tutorial
	1392 - tutorial-roofit-rf903_numintcache-py (Failed)     tutorial
	1396 - tutorial-roostats-IntervalExamples-py (Failed)    tutorial
	1397 - tutorial-roostats-MultivariateGaussianTest-py (Failed) tutorial
	1403 - tutorial-roostats-rs101_limitexample-py (Failed)  tutorial
	1405 - tutorial-roostats-rs401c_FeldmanCousins-py (Failed) tutorial
	1407 - tutorial-roostats-rs701_BayesianCalculator-py (Failed) tutorial

Test log:
build.log.gz

Reproducer

• Build root 6.34.02 with gcc 15 on Fedora 42.
• Run tests.

ROOT version

root 6.34.02 built with gcc 15 (default compiler) on Fedora 42.

Installation method

Build from source.

Operating system

Fedora 42

Additional context

No response

[ellert]

The 6 failures not related to roofit/roostats are fixed by #17551.

[ellert]

The failure in test tutorial-roofit-rf802_mcstudy_addons is fixed by backporting commit 456d542 from master to the 6.34 branch.

The remaining failures all seem to have a common cause. They are all python tests for roofit/roostats, and they all report the following error:

input_line_50:1:16: error: explicit instantiation of 'std::__hash_not_enabled' must occur in namespace 'std'
template class __hash_not_enabled<RooRealVar>;
               ^
/usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/functional_hash.h:84:12: note: explicit instantiation refers here
    struct __hash_not_enabled
           ^