[core] use one instead of two lookups within TClass::Init()

[ferdymercury]

This Pull request:

Changes or fixes:

Fixes #7123

Checklist:

• tested changes locally
• updated the docs (if necessary)

[phsft-bot]

Build failed on ROOT-ubuntu2204/nortcxxmod.
Running on root-ubuntu-2204-1.cern.ch:/home/sftnight/build/workspace/root-pullrequests-build
See console output.

[phsft-bot]

Build failed on ROOT-performance-centos8-multicore/soversion.
Running on olbdw-01.cern.ch:/data/sftnight/workspace/root-pullrequests-build
See console output.

[phsft-bot]

Build failed on mac12arm/cxx20.
Running on 194.12.161.128:/Users/sftnight/build/workspace/root-pullrequests-build
See console output.

[phsft-bot]

Build failed on ROOT-ubuntu2004/python3.
Running on root-ubuntu-2004-1.cern.ch:/home/sftnight/build/workspace/root-pullrequests-build
See console output.

Errors:

• [2024-02-24T10:08:15.566Z] FAILED: tmva/sofie/test/CMakeFiles/SofieCompileModels_ROOT.util

[ferdymercury]

Thanks for the review. I reverted to the original behavior as suggested, but the problem is still there.

Maybe the problem is that TClingClassInfo::TClingClassInfo(cling::Interpreter *interp, const Decl* decl) sets the decl found by CheckClassInfo, which was called without template instantiation. In contrast, TClingClassInfo::TClingClassInfo(cling::Interpreter *interp, const char *name, bool instantiateTemplate /* = true */) is (almost always) called with instantiateTemplate set to true (unless "IsUnloading").

So maybe this issue is a won't fix as the calls are fundamentally different and not reusable?

[github-actions]

Test Results

     6 files      6 suites   2d 5h 28m 1s ⏱️
 2 730 tests   851 ✅   5 💤  1 874 ❌
15 624 runs  4 863 ✅ 372 💤 10 389 ❌

For more details on these failures, see this check.

Results for commit b56c8d3.

♻️ This comment has been updated with latest results.

[pcanal]

trying to reset new CI

[pcanal]

@phsft-bot build

[ferdymercury]

trying to reset new CI

Maybe rebasing and force pushing does the trick?

[pcanal]

Closing and reopening sorta worked: https://github.com/root-project/root/actions/runs/8574933039/job/23502827111?pr=14760 but the 'check' page is not seeing them. So far the failure are 'only' failed S3 connections.