[RF][RS] Deprecate RooStats::HybridPlot

The `RooStats::HybridPlot` class is a helper class for plotting of fit
results, but we are moving towards removing these helpers out of RooFit
because plotting code is better written by the user directly, for better
customizability of the plots.

This is similar to the deprecation and removal of HistFactory plotting
features (see 59da6b1 and 88b2fa1).

Author: guitargeek

README/ReleaseNotes/v640/index.md

@@ -51,6 +51,8 @@ The following people have contributed to this new version:
 * The overloads of `RooAbsReal::createChi2()` and `RooAbsReal::chi2FitTo()` that take unbinned **RooDataSet** data objects are deprecated and will be removed in ROOT 6.42.
   These methods implemented a specialized chi-square fit for x-y-data with errors in y and optional errors in x, which is conceptually different from the standard histogram-based chi-square in the **RooDataHist** case and can lead to ambiguous results.
   To fit 2D data with errors in and `x` and `y`, use specialized tools like `TGraphErrors::Fit()`, or build an explicit likelihood model if you want to stay with RooFit.
+* The **RooStats::HybridPlot** class and the related **HybridResult::GetPlot** method are deprecated and will be removed in ROOT 6.42.
+  We kindly ask users to write their own ROOT-based plotting code, possibly based on the source code of the deprecated **HybridPlot** class, as pre-existing plot helpers are usually failing to be flexible enough for large-scale adoption.
 
 ## Removals
 

roofit/roostats/inc/RooStats/HybridPlot.h

@@ -119,7 +119,11 @@ namespace RooStats {
       bool fVerbose;              ///< verbosity flag
 
       ClassDefOverride(HybridPlot,0)   // Provides the plots for an HybridResult
-   };
+   }
+#ifndef ROOFIT_BUILDS_ITSELF
+   R__DEPRECATED(6, 42, "Please write your own ROOT-based plotting code, possibly based on the source code of the deprecated HybridPlot class.")
+#endif
+   ;
 }
 
 #endif

roofit/roostats/inc/RooStats/HybridResult.h

@@ -45,7 +45,8 @@ namespace RooStats {
 
       void Add(HybridResult* other);
 
-      HybridPlot* GetPlot(const char* name,const char* title, int n_bins);
+      HybridPlot* GetPlot(const char* name,const char* title, int n_bins)
+      R__DEPRECATED(6, 42, "Please write your own ROOT-based plotting code, possibly based on the source code of the deprecated HybridPlot class.");
 
       void PrintMore(const char* options);
 

roofit/roostats/src/HypoTestInverter.cxx

@@ -44,7 +44,6 @@ call HypoTestInverter::UseCLs().
 #include "RooStats/ToyMCSampler.h"
 #include "RooStats/HypoTestPlot.h"
 #include "RooStats/HypoTestInverterPlot.h"
-#include "RooStats/HybridResult.h"
 
 #include "RooAbsData.h"
 #include "RooRealVar.h"

roofit/roostats/src/HypoTestInverterPlot.cxx

@@ -23,7 +23,6 @@ hypotheses.
 #include "RooStats/HypoTestInverterPlot.h"
 
 // include other header files
-#include "RooStats/HybridResult.h"
 #include "RooStats/HypoTestInverterResult.h"
 #include "RooStats/HypoTestPlot.h"
 #include "RooStats/SamplingDistribution.h"

roofit/roostats/src/HypoTestInverterResult.cxx

@@ -22,7 +22,6 @@ Some contributions to this class have been written by Matthias Wolf (error estim
 // include header file of this class
 #include "RooStats/HypoTestInverterResult.h"
 
-#include "RooStats/HybridResult.h"
 #include "RooStats/SamplingDistribution.h"
 #include "RooStats/AsymptoticCalculator.h"
 #include "RooMsgService.h"