Enable DerivePointerAlignment in clang-format

[smuzaffar]

To avoid a massive code formatting with LLVM21, as proposes in https://github.com/cms-sw/cmssw/pull/49293/changes#diff-1026e0038b722990204a42bed8a6f7c0ec2302aa79e3fad1959d62ba968edfa2R18, this PR suggested to enable DerivePointerAlignment code-format option. This should allow us a minimal code formatting change with new LLVM 21.

Without this change clang format form LLVM21 will try to format nearly all files. This should go in 23h00 IB so that new LLVM21 only suggest minimal changes (only order of 100 files should be re-formatted with new LLVVM21 and this change)

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-50060/47921

[cmsbuild]

A new Pull Request was created by @smuzaffar for master.

It involves the following packages:

• .clang-format (core)

@Dr15Jones, @cmsbuild, @makortel, @smuzaffar can you please review it and eventually sign? Thanks.
@ftenchini, @mandrenguyen, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[smuzaffar]

please test

though there is nothing to test

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-50060/47923

[smuzaffar]

@cms-sw/orp-l2 , it would be nice to get this merged before the 23h00 IB.

[smuzaffar]

@makortel , any objections? we should get the in before 23h00 IB which will have new LLVM 21

[makortel]

+core

Sounds good to me

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs after it passes the integration tests. This pull request will now be reviewed by the release team before it's merged. @sextonkennedy, @ftenchini, @mandrenguyen (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1

Size: This PR adds an extra 16KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d52cfc/51159/summary.html
COMMIT: 6166898
CMSSW: CMSSW_16_1_X_2026-02-06-1100/el8_amd64_gcc13
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmssw/50060/51159/install.sh to create a dev area with all the needed externals and cmssw changes.

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:

• @bsunanda Phase2-hgx365K The ordering of wafer types corrected and also ID from position is corrected for HGCal #50043

You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d52cfc/51159/git-recent-commits.json
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d52cfc/51159/git-merge-result

Comparison Summary

Summary:

• You potentially added 5 lines to the logs
• ROOTFileChecks: Some differences in event products or their sizes found
• Reco comparison results: 8428 differences found in the comparisons
• DQMHistoTests: Total files compared: 52
• DQMHistoTests: Total histograms compared: 4031484
• DQMHistoTests: Total failures: 165111
• DQMHistoTests: Total nulls: 225
• DQMHistoTests: Total successes: 3866128
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 51 files compared)
• Checked 222 log files, 193 edm output root files, 52 DQM output files
• TriggerResults: found differences in 3 / 50 workflows

[smuzaffar]

@cms-sw/orp-l2 , can we get this merged for 23h00 IB ?

[smuzaffar]

@cms-sw/orp-l2 , I am merging this otherwise next IB with LLVM21 will propose unnecessary code format changes