Complete the FairRoot provenance notes and guard unused geometry import

This addresses review comments on the imported FairRoot sources.

- AUTHORS and CONTRIBUTORS are copied from FairRoot, as COPYRIGHT refers to them.
- Each modified file carries a short note below its licence header, and the README dates the changes.
- FairModule stops with a message instead of crashing if the FairRoot geometry import is used, and an orphaned declaration is removed.
- A duplicate link in Generators, a blank line in the CPV tests and a stale documentation link are removed.

https://its.cern.ch/jira/browse/O2-7305

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: sawenzel

Detectors/3rdparty/FairRootBase/AUTHORS

@@ -0,0 +1,6 @@
+Al-Turany, Mohammad
+Karabowicz, Radoslaw
+Klein, Dennis
+Kresan, Dmytro
+Rybalchenko, Alexey
+Uhlig, Florian

Detectors/3rdparty/FairRootBase/CMakeLists.txt

@@ -9,17 +9,7 @@
 # granted to it by virtue of its status as an Intergovernmental Organization
 # or submit itself to any jurisdiction.
 
-# FairRootBase: the FairRoot simulation base classes, vendored into O2.
-#
-# These files are copied verbatim from ALICE's own FairRoot fork
-# (alisw/FairRoot, v18.4.9-alice3) so that O2 no longer needs FairRoot as an
-# external package. They remain LGPLv3 (see the per-file headers), which is
-# compatible with O2's GPLv3.
-#
-# The classes deliberately keep their original names and header names in this
-# first step: that makes the move a pure relocation with no call-site changes,
-# so it can be validated as behaviour-preserving. Renaming them into an O2
-# namespace, and pruning the parts O2 does not use, are follow-up steps.
+# FairRootBase: the FairRoot simulation classes used by O2. Origin, licence and changes are in README.md.
 
 # o2_target_root_dictionary requires paths relative to the current source dir
 file(GLOB FAIRROOTBASE_SOURCES CONFIGURE_DEPENDS

Detectors/3rdparty/FairRootBase/CONTRIBUTORS

@@ -0,0 +1,39 @@
+Aphecetche, Laurent
+Babai, Arya
+Berzano, Dario
+Bertini, Denis
+Binet, Sebastien
+Costanza, Susanna
+Eulisse, Giulio
+Friese, Volker
+Gertsenberger, Konstantin
+Hřivnáčová, Ivana
+Klasen, Roman
+Kliemt, Ralf
+Klenze, Philipp
+Kollegger, Thorsten
+Koenig, Ilse
+Krzewicki, Mikolaj
+Lavezzi, Lia
+Lavrik, Evgeny
+Lantwin, Oliver
+Manafov, Anar
+Mayer, Jan
+Neskovic, Gvozden
+Neubert, Sebastian
+Ovcharenko, Egor
+Pellegrino,Carmelo
+Pierre-Alain, Loizeau
+Pflueger, Stefan
+Richter, Matthias
+Rademakers, Fons
+Rohr, David
+Shahoyan, Ruben
+Stockmanns, Tobias
+Tacke, Christian
+Ustyuzhanin, Andrey
+von Haller, Barthélémy
+Wenzel, Sandro
+Wielanek, Daniel
+Winckler, Nicolas
+Zanetti, Lorenzo

Detectors/3rdparty/FairRootBase/README.md

@@ -8,13 +8,15 @@ ALICE has been building against.
 
 The files keep their original copyright and licence headers. FairRoot is distributed under the GNU
 Lesser General Public Licence version 3. The licence text is in [LICENSE](LICENSE) and the copyright
-statement in [COPYRIGHT](COPYRIGHT), both copied verbatim from FairRoot.
+statement in [COPYRIGHT](COPYRIGHT), with [AUTHORS](AUTHORS) and [CONTRIBUTORS](CONTRIBUTORS), all copied verbatim
+from FairRoot. Each modified file carries a note below its licence header.
 
-Changes with respect to the upstream sources:
+Changes with respect to the upstream sources, made in 2026:
 
 - Code paths that O2 does not use were removed. This covers the runtime parameter database and the
   geometry parameter containers, among others. The affected files are `FairMCApplication`,
   `FairModule`, `FairRun`, `FairRunSim`, `FairSink` and `FairField`.
+- `FairModule` stops with a clear message if its geometry import is used, since O2 does not set it up.
 - `FairRootBaseLinkDef.h` is new and builds one dictionary for the directory.
 
 The sources keep their upstream formatting and are excluded from clang-format.

Detectors/3rdparty/FairRootBase/include/FairField.h

@@ -5,6 +5,7 @@
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 // -------------------------------------------------------------------------
 // -----                      FairField header file                     -----
 // -----                Created 06/01/04  by M. Al-Turany              -----

Detectors/3rdparty/FairRootBase/include/FairModule.h

@@ -5,6 +5,7 @@
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 #ifndef FAIRMODULE_H
 #define FAIRMODULE_H
 
@@ -116,7 +117,6 @@ class FairModule : public TNamed
      **/
     void SetMotherVolume(TString volName) { fMotherVolumeName = volName; }
     /**called from ConstuctASCIIGeometry*/
-    void ProcessNodes(TList* aList);
     /**Set the parameter containers*/
     virtual void SetParContainers() { ; }
     /** Initialize everything which has to be done before the construction and modification

Detectors/3rdparty/FairRootBase/include/FairRun.h

@@ -5,6 +5,7 @@
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 #ifndef FAIRRUN_H
 #define FAIRRUN_H
 

Detectors/3rdparty/FairRootBase/include/FairRunSim.h

@@ -5,6 +5,7 @@
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 #ifndef FAIRRUNSIM_H
 #define FAIRRUNSIM_H
 

Detectors/3rdparty/FairRootBase/include/FairSink.h

@@ -5,6 +5,7 @@
  *         GNU Lesser General Public Licence version 3 (LGPL) version 3,        *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 // -----------------------------------------------------------------------------
 // -----                                                                   -----
 // -----                             FairSink                              -----

Detectors/3rdparty/FairRootBase/src/FairMCApplication.cxx

@@ -5,6 +5,7 @@
  *              GNU Lesser General Public Licence (LGPL) version 3,             *
  *                  copied verbatim in the file "LICENSE"                       *
  ********************************************************************************/
+// Modified for ALICE O2 in 2026: parts not used by O2 were removed (see README.md in this directory).
 // -------------------------------------------------------------------------
 // -----               FairMCApplication source file                   -----
 // -----            Created 06/01/04  by M. Al-Turany                  -----