Pass by reference when null is not expected

[sharwell]

No description provided.

[codecov]

Codecov Report

Merging #4546 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4546      +/-   ##
==========================================
+ Coverage    75.1%   75.11%   +<.01%     
==========================================
  Files         908      908              
  Lines      160260   160260              
  Branches    17259    17259              
==========================================
+ Hits       120369   120379      +10     
+ Misses      35070    35067       -3     
+ Partials     4821     4814       -7

Flag	Coverage Δ
#Debug	75.11% <ø> (ø)	⬆️
#production	70.51% <ø> (ø)	⬆️
#test	90.26% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
src/Microsoft.ML.AutoML/Sweepers/Parameters.cs	78.81% <0%> (-4.24%)	⬇️
...soft.ML.Data/DataLoadSave/Text/TextLoaderCursor.cs	84.7% <0%> (-0.41%)	⬇️
...ML.Transforms/Text/StopWordsRemovingTransformer.cs	86.1% <0%> (-0.16%)	⬇️
src/Microsoft.ML.Maml/MAML.cs	26.21% <0%> (+1.45%)	⬆️
...rosoft.ML.AutoML/ColumnInference/TextFileSample.cs	62.25% <0%> (+2.64%)	⬆️
....ML.AutoML/PipelineSuggesters/PipelineSuggester.cs	86.55% <0%> (+6.72%)	⬆️
...c/Microsoft.ML.FastTree/Utils/ThreadTaskManager.cs	100% <0%> (+20.51%)	⬆️

[codemzs]

[codemzs]

Thanks but can you please the rationale for passing by reference instead of pointers?

[sharwell]

The method uses the object without checking it for null, so it's clear that it never expects a null pointer as input. References are an idiomatic way of expressing intent in C++ that the input is not expected to be null, and is used by the method but not stored by the method for later use (i.e. the scope of use extends to the return from the method, and no further).